Above the Clouds with Diabetes: From Pathophysiological Considerations to Practical Recommendations for Safe Flights

Abstract

Vasdeki, Dimitra, Georgios Tsamos, Kleoniki I. Athanasiadou, Vasiliki Michou, Evangelos Botsarakos, Michael Doumas, Kalliopi Kotsa, and Theocharis Koufakis. Above the clouds with diabetes: from pathophysiological considerations to practical recommendations for safe flights. High Alt Med Biol. 26:87–98, 2025.

Background:

Methods:

This narrative review summarizes the existing evidence on the intriguing association between diabetes and air travel, analyzes safety and certification protocols, and provides practical recommendations for the management of diabetes during flights.

Results:

During air travel, individuals with diabetes face challenges arising from inappropriate dietary options, restricted access to medications and healthcare services, disruption of medication dosing intervals, and exposure to hypobaric conditions in the airplane cabin. In addition, people with diabetes, especially those treated with insulin, have traditionally been considered ineligible to become professional pilots. However, this approach gradually changes and numerous countries are now implementing strict protocols to determine the eligibility of pilots with diabetes to operate flights.

Conclusions:

Given the increasing use of technology and new drugs in daily clinical practice, there is a need for further research in the field to shed light on existing knowledge gaps and ensure safe flights for people with diabetes.

Introduction

The prevalence of diabetes mellitus has been following an increasing trend in the last decades, leading to a growing number of travelers with diabetes seeking pretravel advice from medical professionals (Centers for Disease Control and Prevention, 2017; Elfrink et al., 2014). During air travel, individuals with diabetes face challenges arising from inappropriate dietary options, restricted access to medications and healthcare services, disruption of medication dosing intervals, and exposure to hypobaric conditions in the airplane cabin. The perturbation of routine dosing intervals becomes more noticeable when travelers traverse multiple time zones. The east or west direction of the flight compresses or elongates the temporal interval between scheduled doses, respectively. This increases the probability of unplanned, premature, or delayed administration of antihyperglycemic therapy. Travelers must devise strategies to deal with the complexities of crossing multiple time zones, including insulin administration planning, the biological consequences of jet lag, and individual susceptibility to hypoglycemic episodes at high altitudes (Transcend Glucose Gels/Travelling With Diabetes/Flying With Diabetes, 2017).

Furthermore, people with diabetes occasionally perceive themselves as subject to unfair discrimination within the occupational setting, particularly when referring to safety-critical procedures, such as machinery operation and professional driving (Inkster and Frier, 2013; Wientjens and Cairns, 2012). This bias is especially pronounced among people reliant on insulin therapy, who are routinely excluded from safety-sensitive occupations owing to the inherent risk of hypoglycemia and the probability of complications that could jeopardize public safety (i.e., coronary heart disease). The threat of hypoglycemia and the resultant incapacitation is the rationale most frequently cited for implementing a blanket prohibition policy, precluding individuals from engaging in safety-critical occupations (Wientjens and Cairns, 2012).

In 2011, the International Diabetes Federation inaugurated the first international charter of rights and responsibilities dedicated to individuals with diabetes. This pioneering document incorporated the entitlement to social justice harmonized with public safety (International Diabetes Federation, 2012). However, the regulations established by the European Aviation Safety Agency categorically disallow aeromedical certification for commercial air transport pilots with Type 1 diabetes mellitus (T1DM) and Type 2 diabetes mellitus (T2DM) managed with insulin. In a notable deviation from the regulations mentioned above, the Civil Aviation Authorities of the United Kingdom (UK), Ireland, and Austria extend approval to pilots with all types of insulin-treated diabetes mellitus (ITDM), depending on adherence to a meticulously outlined protocol featuring stringent entry and operational requirements (Mitchell et al., 2017). However, this particular exemption and its accompanying protocol have received criticism from other European member states. The main points of disagreement revolve around the practicality of in-flight glucose measurements for ITDM pilots and the fact that striving for low enough glycemic targets to avert macro- and microvascular diabetic complications could increase the risk of hypoglycemia during flight. On the contrary, proponents argue that targeting glycated hemoglobin levels of 7%, as advocated by the American Diabetes Association (ADA), allows pilots to maintain safe glucose levels during flight within the range of 100–130 mg/dl (5.6–7.2 mmol/l) (Simons et al., 2014).

Modern diabetes management, marked by advances in insulin therapy and glucose monitoring, coupled with meticulous clinical evaluation and scrutiny, has successfully challenged ingrained stereotypes surrounding people with diabetes. During the past two decades, several national authorities have allowed private pilots with ITDM to participate in recreational flights (Simons et al., 2014). In light of these advances, it is not surprising that a significant proportion of diabetes patients, particularly those embarking on long flights, seek more comprehensive travel guidance (Burnett, 2006). However, a lack of knowledge among healthcare professionals about the proper management of diabetes medications during air travel can result in a subset of patients receiving inadequate or potentially hazardous guidance (Gill and Redmond, 1993). Consequently, the formulation of guidelines designed for passengers and pilots with diabetes during flights has gained increased importance in recent years. In this context, our objective was to distill a summary of the existing literature in the field, identify areas of consensus and potential knowledge gaps, and highlight issues warranting further investigation.

Exploring the Impact of High Altitude on the Pathophysiology of Diabetes

In 2014, the International Society for Mountain Medicine defined high altitude as ranging from 1,500 to 3,500 m (5,000 to 11,500 feet), very high altitude spanning 3,500–5,500 m (11,500 to 18,000 feet) and extreme altitude, denoting elevations above 5,500 m (18,000 feet) (Brodmann Maeder et al., 2018). Numerous investigations have examined fasting glucose levels in individuals with sound health exposed acutely and chronically to high altitudes. The findings reveal a spectrum of outcomes, including increases, decreases, or no significant changes, with the disparity attributed to the duration of altitude exposure (Koufakis et al., 2019; Larsen et al., 1997; Sawhney et al., 1986; Stock et al., 1978; Woolcott et al., 2015). Most studies suggest an initial surge in glucose levels at higher altitudes, followed by a subsequent decline as individuals acclimatize over prolonged exposure periods. The interplay of altitude, sympathetic activity during exercise, and increased catecholamine levels is believed to be the basis of these physiological phenomena (Thomas SR, 2001; Rostrup, 1998). Multiple studies consistently demonstrate elevated plasma and urinary catecholamines in response to acute altitude exposure (Woolcott et al., 2015). Furthermore, some researchers propose that the reported elevation in cortisol levels during short-term high-altitude exposure may also contribute to hyperglycemia. These hormones can also be affected by the fight-or-flight response, which includes a variety of catabolic, antireproductive, antigrowth, and immunosuppressive processes (Sharma et al., 2022). In contrast, reduced blood glucose levels have been observed after acute exposure to hypobaric hypoxia in people without diabetes during long fasting periods (Woolcott et al., 2015).

Owing to barometric pressure, the decrease in ambient pressure within the aircraft cabin during the ascent to its cruising altitude triggers an expansion of gases of approximately 30% (UK CAA, 2024.). On the contrary, during descent for landing, the increasing cabin pressure prompts a commensurate reduction in volume. The presence of gas within bodily cavities can pose challenges when it becomes confined and unable to expand unencumbered, or if there are impediments to the free flow of air, hindering the equalization of air pressure. This phenomenon, as well as emergency decompression, can affect the efficacy of medical devices, including insulin pumps, owing to the formation and expansion of air bubbles, potentially resulting in the delivery of excessive or insufficient medication due to abrupt pressure changes and hypobaric hypoxia (Bagshaw and Illig, 2019; UK CAA, 2024.). It is crucial to recognize that additional factors, such as the unintentional release of insulin from pumps through tubing owing to fluctuations in pressure and dissolved gases, can have a more substantial influence in such situations (King et al., 2011). Therefore, the guidelines issued by both the UK and the European Union (EU) for people with diabetes who fly underscore the need to ingest carbohydrates during an emergency decompression. This proactive measure is suggested to ameliorate the potentially harmful consequences of excessive insulin release from pumps during critical circumstances (King et al., 2011).

Undoubtedly, the main influencers of plasma glucose levels at altitude during air travel include diet modifications, lack of physical activity, and timing of carbohydrate and food intake with respect to insulin administration. These factors are expected to exert a significantly more pronounced impact compared with the relatively minor effects resulting from acute pressure changes. Currently, there is a scarcity of data on the consequences of pressure variations in individuals with diabetes at elevated altitudes in the absence of exercise. Consequently, although subtle changes in overall glucose metabolism can manifest in response to acute pressure changes, their significance is considered minor when juxtaposed with the profound influence of dietary changes and the sedentary nature of air travel.

Navigating the Skies: Pursuing a Career as a Professional Pilot with Type 1 or 2 Diabetes Mellitus

Numerous countries have implemented protocols to determine the eligibility of pilots with diabetes to operate flights. These protocols share a typical structure, which features a comprehensive clinical assessment focused on hypoglycemia awareness, detection, and surveillance of complications, and proficiency in self-management of diabetes. Although the evaluation includes measurements within the 30 minutes before take-off and landing, there are variations in the procedures during the actual flight (UK Civil Aviation Authority, 2018).

To guarantee a safe aviation experience, pilots with T1DM or T2DM who are on insulin treatment should carry two glucometers capable of measuring and recording blood glucose values. In addition, they should ensure they have a large supply of glucose measuring strips to analyze blood samples. In the event of a need, it is essential to have a sufficient amount of rapidly absorbable glucose, such as glucose tablets or sugar cubes, readily available throughout the duration of the flight (Handbook of Civil Aviation Medical Examiners-TP 13312, 2024). A “traffic light” system has been introduced to govern acceptable pre- and in-flight glucose levels to ensure standardized monitoring. Under this system, a green sign means “acceptable,” amber indicates the need for “caution” and red demands immediate action. In instances of low amber values, pilots are required to consume 10–15 g of readily absorbed carbohydrates and retest glucose after 30 minutes. On the contrary, low red values require the transfer of duties to the copilot or, in the case of solo flights, prompt consideration of landing. In such situations, pilots are advised to ingest 10–15 g of readily absorbed carbohydrates and retest capillary blood glucose after 15 minutes (Høi-Hansen et al., 2010) (Table 1).

Table 1.

Preflight and In-Flight Guidelines for Glucose Control

Optimal time for the pilot to gauge their blood glucose	Blood glucose measurements	How ought the pilot respond in this scenario?
Preflight check: 30 minutes before takeoff (and no insulin within 90 minutes of flight).	>15 (mmol/l) or >270 (mg/dl) 5–15 (mmol/l) or 90–270 (mg/dl) <5 (mmol/l) or <90 (mg/dl)	- Opt to abort the flight. - Continue with the scheduled flight. - Consume 15 g of carbohydrates and reevaluate blood glucose in 30 minutes.
In-flight check: In the initial 30 minutes after takeoff. Subsequently, check hourly during the flight and within the last 30 minutes before the expected landing.	>15 (mmol/l) or >270 (mg/dl) 5–15 (mmol/l) or 90–270 (mg/dl) <5 (mmol/l) or < 90 (mg/dl)	- Land and refrain from resuming flight control until blood glucose levels are between 5–15 mmol/l (90–270 mg/dl). - No immediate action is necessary. - Consume 30 g of carbohydrates, land, and avoid resuming flight until blood glucose levels are within the range of 5–15 mmol/l (90–270 mg/dl).
In the case of conflicting operational priorities during the flight.	Measurement is not feasible.	Consume 15 g of carbohydrates and monitor blood glucose levels in 1 hour. If unable to check at this time, ingest 30 g of carbohydrates and land to assess blood glucose levels.

Table 2 presents a comprehensive overview of the certification protocols applicable to pilots undergoing insulin treatment, whether T1DM or T2DM, in various parts of the world such as Canada, the UK, Israel, the EU, New Zealand, and the United States. In the case of pilots who manage T2DM exclusively through lifestyle measures, the risk of hypoglycemia is similar to that of individuals without diabetes. However, the risk increases significantly for pilots who receive sulfonylureas or insulin. In particular, for individuals treated with sulfonylureas or glinides, the recommendations on the frequency of glucose measurements during flight vary. Specifically, UK, EU, and New Zealand guidelines require pilots to monitor their glucose levels at least every 2 hours during flight operations. This underscores the critical importance of meticulous glucose management for pilots with diabetes, especially those taking specific medications that pose an elevated risk of hypoglycemia during flight. Although the literature lacks information on other antidiabetic drugs, it is imperative to consider incorporating sodium glucose cotransporter 2 (SGLT2) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists, or dipeptidyl peptidase 4 (DPP-4) inhibitors into the arsenal of suitable medications for aviators with T2DM. This recommendation comes as a result of the widespread prescription of these medications gradually replacing sulfonylureas and glinides and their low risk of inducing hypoglycemia.

Table 2.

An Overview of Flight Protocols Across Different Countries

Protocol with insulin	Comprehensive clinical assessment/ophthalmology check	Glucose monitoring	Frequency of glucose measurements in flight	HbA1c assessment	Complication surveillance	Range of acceptability during flying
United Kingdom	✓	Blood test	30 minutes before takeoff and landing, every 1 hour during flight	Semesterly	Yearly	5–15 mmol/l (90–270 mg/dl)
European Union	✓	Blood test	30 minutes before takeoff and landing, every 1 hour during flight	Semesterly	Yearly	5–15 mmol/l (90–270 mg/dl)
Canada	✓	Blood test	30 minutes before takeoff and landing, every 30 minutes during flight	Semesterly	Yearly	6–15 mmol/l (108–270 mg/dl)
United States	✓	Continuous glucose monitoring	Continuous monitoring	Each trimester	Yearly	4.4–10 mmol/l (79–180 mg/dl)
New Zealand	✓	Blood test	30 minutes before takeoff and landing, every 1 hour during flight	Unspecified	Yearly	>5.5 mmol/l (99 mg/dl)
Israel	✓	Blood test	30 minutes before takeoff and landing, every 2 hours during flight	Each trimester	Yearly	>5.5 mmol/l (99 mg/dl)

Medical Certifications

Various classes of medical certificates cater to different categories of pilots. These include Class 1 for professional pilots (holders of air transport pilot, commercial pilot, flight engineer, or flight navigator licenses), Class 2 for private pilots (applicable to holders of student pilot or private pilot licenses), and commercial pilots with specific operational restrictions (pertaining to commercial aircraft pilots not carrying passengers and operating aircraft weighing less than 8,618 kg, as well as commercial balloon pilots). In addition, there is Basic Class 2 designed for private pilots, limited to piston engine-powered aircraft, day visual flight rules, and the carriage of up to five nonfare paying passengers. Lastly, Class 3 is designated for air traffic controllers (ICAO, 2024.).

Over time, the guidelines for aeromedical certification and policies for pilots with diabetes have undergone refinement and modification. Individuals managing diabetes through diet, oral medications, or noninsulin injectables (GLP-1 receptor agonists) can qualify for Class 1, 2, or 3 licenses, subject to demonstrating stable blood glucose levels through home blood glucose monitoring and the absence of complications. Presently, regulations dictate that people with ITDM (Type 1 and 2) are accepted to have Class 1 or Class 3 medical certificates (ICAO, 2024.). Table 3 provides a summary of global standards for the medical certification of pilots on insulin therapy.

Table 3.

A Summary of Global Standards for the Medical Certification of Pilots on Insulin Therapy

	United Kingdom	United States	Canada	Australia
Class 1	Approved with copilot (starting from 2012).	Approved (from 2019 onward).	Approved pending risk stratification (starting from 2012).	Unsuitable
Class 2	Permissible with the presence of a safety pilot and dual controls.	Permitted for solo flight upon passing a medical assessment (since 1996).	Approved, subject to risk stratification.	Serve with a co-pilot for 15 flights, followed by a review for solo eligibility.
Class 3	Unsuitable	Permissible	Permissible	Unsuitable
Insulin injections	Approved	Approved	Approved	Approved
Insulin pumps	Approved	Approved	Approved	Not approved, and the matter is not addressed in the protocol.
Last assessment date	November 2018	November 2019	March 2015	May 2017

Considerations for Airline Passengers with Diabetes

A concise guide to air travel

Several articles have been published, mainly based on expert opinions, to formulate recommendations about air travel for people with diabetes. A consensus has emerged, indicating that patients with diabetes can safely embark on air travel, provided they are well prepared. However, caution or potential delay in travel plans is advised for newly diagnosed or poorly controlled individuals (Shand, 2000). The counsel encompasses a wide spectrum, covering aspects such as education, behavioral considerations, provisions of necessary supplies and devices, medication management, and documentation. In particular, the guidance takes into account various factors to ensure a comprehensive approach to the well-being of individuals with diabetes during air travel. It should be noted that there are some contraindications to flying, such as unstable retinopathy or recent argon photocoagulation for diabetic retinopathy, owing to the relatively hypoxic conditions of the cabin environment, although it is crucial to highlight that such cases are rare (Mileno and Bia, 1998; Suh and Mileno, 2005). Table 4 provides comprehensive guidelines for people with diabetes during air travel.

Table 4.

Comprehensive Guidelines for Air Travel: General Recommendations

Informative guidance (Alsafadi et al., 2011; Benson and Metz, 1984; Bia and Barry, 1992; Brubaker, 2005; Burnett, 2006; Canadian Paediatric Society, 2007; Chandran and Edelman, 2003; Cross J et al., 2008; D Dunning, 1989; Frier and Strachan, 2010; Gill and Redmond, 1993; Patterson TFPFJBMB, 1989; Jornsay, 1998; Levy-Shraga et al., 2014; MacNeill and Fredericks, 2015; Mileno and Bia, 1998; Nassar et al., 2012; Pray, 1996; R E Thomas, 2000; S A Ross, 1985; Suh and Mileno, 2005; Sullivan, 2016)	• Obtain personalized guidance from a diabetes clinic and a registered dietitian before embarking on your journey. • Familiarize yourself with patient-centric recommendations from reputable national diabetes organizations. • Notify the airline about your diabetes diagnosis and necessary medications well in advance of your travel date. • Ensure that your travel companions are informed about your diabetes diagnosis, recognize the signs of hypoglycemia, and are familiar with appropriate treatment measures, including administering glucagon.
Behavioral practices (Aerospace Medical Association Medical Guidelines Task Force, 2003; Alsafadi et al., 2011; Benson and Metz, 1984; Brubaker, 2005; Burnett, 2006; Holmwood and Phillips, 1997; Chandran and Edelman, 2003; Cross J et al., 2008; D Dunning, 1989; Dewey and Riley, 1999; Driessen et al., 1999; Fatema Jawad, 2016; Frier and Strachan, 2010; Gill and Redmond, 1993; Patterson TFPFJBMB, 1989; Jones et al., 1994; Jornsay, 1998; Kaplan et al., 1998; Levy-Shraga et al., 2014; M J MacDonald, 1983; McCarthy, 2004; Moran and Burson, 2014; Nassar et al., 2012,; Pray, 1996; S A Ross, 1985; S Cradock, 1997; Saskatchewan health, 2010; Shand, 2000; Suh and Mileno, 2005; Sullivan, 2016; Bettes and McKenas, 1999; Walker and Williams, 1983)	• Anticipate unforeseen delays in your travel plans and make contingency arrangements. • Monitor blood glucose levels regularly throughout the actual travel days. • Continue insulin use, adjusting it as needed during episodes of diarrheal or vomiting illnesses. • Recognize that airline meals may not be suitable, especially for individuals with type 1 diabetes. • Refrain from consuming alcohol during the flight and ensure adequate intake of nonalcoholic fluids to maintain hydration. • Pay attention to proper foot care during travel and avoid breaking in new shoes while on the go.
Essential equipment and devices (Aerospace Medical Association Medical Guidelines Task Force, 2003; Alsafadi et al., 2011; Bia and Barry, 1992; Chandran and Edelman, 2003; Cross J et al., 2008; Dewey and Riley, 1999; Ericsson, 2003; Fatema Jawad, 2016; Frier and Strachan, 2010; Patterson TFPFJBMB, 1989; Jornsay, 1998; King et al., 2011; Levy-Shraga et al., 2014; M J MacDonald, 1983; MacNeill and Fredericks, 2015; McCarthy, 2004; Mileno and Bia, 1998; Moran and Burson, 2014; Nassar et al., 2012; Pray, 1996; R E Thomas, 2000; S A Ross, 1985; Saskatchewan health, 2010; Shand, 2000; Sullivan, 2016; Bettes and McKenas, 1999; Walker and Williams, 1983)	• Ensure an ample supply of supplies, doubling the anticipated quantity. • Recommended supplies include glucometers, test strips, lancets, syringes and needles, extra batteries, ketone-detecting urine test strips for travelers with type 1 diabetes, as well as sources of carbohydrates and medicines. • Travelers using insulin pumps should carry injectable insulin as a precaution in case of pump malfunction or failure. It is advisable to bring an additional set of pump-related supplies and consider having a backup pump. • Opt for visual inspection instead of exposing the insulin pump to x-rays during preflight security clearance. • Disconnect the pump during takeoff (or in the event of cabin pressure loss). Once at cruising altitude, remove the insulin cartridge, eliminate bubbles, and reconnect. After landing, disconnect the pump, prime the line, and reconnect. • Disable the “Alarm Silence” feature in the insulin pump during travel. The ambient cabin noise may diminish the ability to hear device alarms, so frequent monitoring on-board the plane is recommended.
Therapeutic drugs (Aerospace Medical Association Medical Guidelines Task Force, 2003; Alsafadi et al., 2011; Benson and Metz, 1984; Bia and Barry, 1992; Brubaker, 2005; Burnett, 2006; Chandran and Edelman, 2003; Cross J et al., 2008; Dewey and Riley, 1999; Ericsson, 2003; Fatema Jawad, 2016; Frier and Strachan, 2010; Izadi et al., 2015; Patterson TFPFJBMB, 1989; Jornsay, 1998; Levy-Shraga et al., 2014; M J MacDonald, 1983; M W Voss, 1983; MacNeill and Fredericks, 2015; McCarthy, 2004; Mileno and Bia, 1998; Mills and Harding, 1983; Moran and Burson, 2014; Nassar et al., 2012; O W Skjenna et al., 1991; Pray, 1996; R E Thomas, 2000; S A Ross, 1985; Saskatchewan health, 2010; Shand, 2000; Suh and Mileno, 2005; Sullivan, 2016; Bettes and McKenas, 1999; Walker and Williams, 1983)	• It is advisable to carry medicines, including insulin, in your carry-on luggage. • Bring sources of carbohydrates such as snacks, glucose tablets, or gels. Consider carrying glucagon if you are traveling with insulin. • Understand the distinctions between insulin strengths (U-300, U-200, U-100, U-80, U-40) and blood glucose measurements (mmol/l vs. mg/dl) in case you need to use local supplies. • Opened vials of insulin generally do not need refrigeration unless in hot climates, but it’s recommended to store insulin in a cool, dry location. Consider using insulated or specialized containers for carrying insulin. Closed vials should be refrigerated. • Consider bringing anti-emetics, antidiarrheals, and topical antibiotics. In addition, think about prophylactic antibiotics for traveler’s diarrhea, urinary tract infections, or fungal skin infections, especially if traveling to high-risk areas.
Written records (Alsafadi et al., 2011; Benson and Metz, 1984; Bia and Barry, 1992; Brubaker, 2005; Holmwood and Phillips, 1997; Chandran and Edelman, 2003; Cross J et al., 2008; D Dunning, 1989; Dewey and Riley, 1999; Fatema Jawad, 2016; Frier and Strachan, 2010; Izadi et al., 2015; Patterson TFPFJBMB, 1989; Jornsay, 1998; Katarzyna Chełmińska, 2002; Levy-Shraga et al., 2014; MacNeill and Fredericks, 2015; McCarthy, 2004; Mileno and Bia, 1998; Moran and Burson, 2014; Nassar et al., 2012; Pray, 1996; S A Ross, 1985; Suh and Mileno, 2005; Sullivan, 2016; Bettes and McKenas, 1999; Walker and Williams, 1983)	• Carry letters from prescribers or pharmacies that detail your medical condition, prescribed medicines, required supplies, and emergency contacts. • Acquire travel insurance or verify that your existing coverage is current. • Ensure that supplies are kept in their original containers with official preprinted pharmacy or manufacturer labels. • Wear identification items, such as medical bracelets. • Maintain a list of doctors and clinics in the native language of the destination.

Packing Materials: Streamlining Your Supplies

Table 5 details indispensable supplies for people with diabetes travelling. It is imperative that these travelers carry up-to-date prescriptions for their medications, insulin, and accompanying supplies. Ensuring that these items align with the traveler’s name on both their ticket and passport is vital to facilitate seamless travel experiences and effectively address unexpected emergency scenarios.

Table 5.

Diabetes Travel Supplies Checklist

Medications^a	- Oral antidiabetic medications. - Other injectable antidiabetic medications (hand-bag only). - Additional prescription medications such as antihypertensives, statins, aspirin, etc. - Medications for nausea, vomiting, diarrhea, and fever. - First aid kit. These supplies can be divided between hand-bag and checked-in bags as needed.
Insulin and associated equipment^a	- Insulin vials, cartridges, and pens (hand-bag only). - Spare insulin pen (hand-bag only). - Syringes and needles.
Glucometer and CGM devices^a	- Glucometer with one spare glucometer. - Spare batteries. - Glucometer test strips.-Lancet needles. - CGM supplies with spare glucometer. - Urine ketone strips (for individuals with type 1 diabetes).
Insulin pump	- Insulin pump worn by the individual. - All pump supplies including insulin cartridges, tubing, etc., exceeding the required amount for the duration of stay. - Extra supplies of insulin pens with needles, containing both rapid and long-acting insulin, for use in case of pump malfunction.
Hypoglycemia management	- Glucose tablets, gels, candies, or liquid drinks. - Glucagon kit for individuals at high risk of hypoglycemia or with hypoglycemia unawareness. - Complex carbohydrate-containing snacks such as cereal bars, cookies, nuts, cheese crackers, etc.

Extra medications beyond the amount needed for the duration of the trip.

CGM, continuous glucose monitoring.

The Transportation Security Administration (TSA) and the ADA advise travelers with diabetes to pack their essential supplies with care (American Diabetes Association, 2004). This includes medications, insulin, needles, glucometers, test strips, and lancets, all preserved in their original packaging with the appropriate labeling. Lancet needles, securely capped and in original packaging, can be carried in hand luggage with the glucometer. Gel packs serve as an effective means to maintain the ideal temperature for insulin storage. To expedite security checks, it is recommended to pack medications and supplies in a separate clear bag for easy inspection.

Prudent preparation involves doubling the amount of medications necessary to accommodate prolonged stays or possible ruptures of vials or cartridges (Chandran and Edelman, 2003). Although half of these supplies can be stowed in checked luggage, a sufficient amount should be retained in hand luggage to address potential mishaps such as lost baggage. Insulin vials, cartridges, pens, glucometers, and test strips should always be stored in hand luggage to protect them from exposure to freezing temperatures (Bettes and McKenas, 1999). In addition, noninsulin injectables such as GLP-1 receptor agonists and glucagon kits should be included in hand luggage. It is imperative to ensure that insulin remains insulated and undergoes a thorough inspection for crystals or cloudiness before use if any of these items are transported in checked baggage.

Guidelines for Adjusting Antihyperglycemic Treatment

Noninsulin regimens

Most experts recommend maintaining regular doses of oral medications during travel, emphasizing the importance of hydration and consistent meal schedules, especially for individuals taking sulfonylureas (Fatema Jawad, 2016; McCarthy AE, 2004; Shand, 2000; Sullivan, 2016). On the other hand, there are recommendations for adjustments to oral regimens, such as incorporating rapid-acting agents such as repaglinide or nateglinide with meals to bridge coverage gaps (Frier and Strachan, 2010; Suh and Mileno, 2005). These adjustments may involve slight, albeit unspecified, dose modifications based on travel direction. Some experts suggest omitting a second dose of certain medications such as metformin, thiazolidinediones, or sulfonylureas during travel, while advocating the continuation of alpha-glucosidase inhibitors and newer nonsulfonylurea secretagogs with meals (Chandran and Edelman, 2003). There are no publications that provide specific recommendations on SGLT2 inhibitors, GLP-1 receptor agonists, or amylin analogs in the context of air travel. Maintaining consistent meal patterns and avoiding meal skips is crucial for travelers to prevent hypoglycemia during flight.

Insulin

Recommendations on insulin adjustment for travelers span a spectrum of approaches, underscoring the need for customized modifications that are in accordance with the unique requirements of each traveler. Preferring streamlined adjustments over intricate ones, there is a tendency to lean toward slightly elevated glucose values during travel days (American Diabetes Association, 2004; Benson and Metz, 1984; Chandran and Edelman, 2003; Gill and Redmond, 1993; Josse and Woo, 2013; Saskatchewan health, 2010). Encouraging the adoption of insulin delivery pens in lieu of needles and syringes, specific advice is offered on the optimal insulin type for travelers, alongside a strong emphasis on regular blood glucose monitoring. For example, suggested strategies involve transitioning patients from premixed insulin formulations to a split basal bolus regimen before travel and selecting rapid-acting analogs over regular insulin (Chandran and Edelman, 2003; Ericsson, 2003; Fatema Jawad, 2016; Suh and Mileno, 2005; Sullivan, 2016). Recent research also highlights the potential benefits of ultra-long-acting insulin degludec for frequent travelers, given its relatively stable state amid scheduling disruptions (Fatema Jawad, 2016; Josse and Woo, 2013). Although the 2004 ADA Insulin Administration Practice Guideline advocates for offering guidance on insulin adjustment for travelers crossing three or more time zones, various studies have proposed different thresholds, ranging from two to seven time zones (American Diabetes Association, 2004).

Although official guidelines on insulin adjustment during travel are currently lacking, some authors offer insights based on clinical experience. Patients often opt to reduce the basal insulin dose to mitigate the risk of hypoglycemia, which can lead to hyperglycemia owing to inadequate prandial doses. Adjusting bolus insulin using self-monitoring of blood glucose and carbohydrate counting is relatively straightforward. However, there remains confusion regarding the adjustment of basal insulin, particularly when crossing time zones. When traveling westward, a long day may require an additional bolus dose. On the contrary, eastward travel shortens the day, potentially requiring a reduction in basal insulin dose if the change in time exceeds 2 hours. It is recommended to halve the basal insulin dose during travel and return to the previous schedule upon arrival.

Insulin pumps/insulin pens

Regarding insulin pumps, common recommendations include frequent blood glucose monitoring and the transport of ample injectable insulin as backup in case of pump failure (Chandran and Edelman, 2003; Cross J et al., 2008; Dewey and Riley, 1999; MacNeill and Fredericks, 2015; Sullivan, 2016). However, some publications advise maintaining the regular basal rate and the premeal bolus regimen during travel, whereas others do not specify any adjustments (Cradock, 1997; Fatema Jawad, 2016; Kaplan et al., 1998; Nassar et al., 2012). According to MacNeil et al., individuals are advised to use the lowest basal rate during the flight if the difference between the basal rates of departure and arrival is minimal and to adjust the pump clock to local time upon arrival (MacNeill and Fredericks, 2015). In cases where departure and arrival basal rates differ significantly, a gradual adjustment of the pump clock over several days is recommended. To ensure the safety of insulin pumps during flight and mitigate the risk of inadvertent insulin delivery at high altitudes, King et al. advocate several precautions: restricting the insulin volume in the pump cartridge to 1.5 ml, disconnecting the pump during take-off and in-flight emergencies, and visually inspecting and eliminating any bubbles in the lines and insulin cartridges before reconnecting the pump (Hermanides et al., 2011). Although there is a consensus among experts regarding the necessity of adjusting insulin pump time settings, there remains uncertainty regarding when to synchronize the pump clock with local time and how to appropriately modify basal rates during travel.

Regarding insulin pens, these devices seem to perform reliably even at high altitudes. However, it is recommended to remove the needles after injection due to the potential for changes in air pressure during ascent and descent. These pressure fluctuations can inadvertently introduce air bubbles and lead to the expulsion of insulin. Table 6 provides a concise overview of suggestions for modifying antihyperglycemic therapy while traveling, also taking into consideration the direction of travel (east or west).

Table 6.

Guidance on Adjustments of Antihyperglycemic Therapy During Air Travel

Noninsulin glucose lowering agents		Travelling in an easterly direction	Travelling in a westerly direction
Metformin	Modify accordingly.	For immediate-release formulations, patients should skip their evening dose on the day of travel. As for extended-release formulations or for those with CKD Stage 3, it is advised to hold the medication on the day of travel.	No adjustments recommended.
Sulfonylureas	Modify accordingly.	For immediate-release formulations, patients should skip their evening dose on the day of travel. As for extended-release formulations, it is advised to hold the medication on the day of travel.	Continue the regular dosing schedule without adjustments. However, if meals are skipped, it is advisable to hold the medication.
Meglitinides	Modify accordingly.	Continue the regular dosing schedule without adjustments. However, if meals are skipped, it is advisable to hold the medication.	Individuals may consider taking an extra dose if an additional meal is consumed.
Thiazolidinedione	Modify accordingly.	Continue with the regular dosing schedule without adjustments but forego taking a second dose.	No adjustments recommended.
α-Glucosidase inhibitors	Continue medication regimen unchanged, ensuring it’s taken with meals.	No adjustments recommended.	No adjustments recommended.
DPP-4 inhibitors	Continue medication regimen unchanged.	For individuals with CKD Stage 3, it is advised to hold the medication on the day of travel.	No adjustments recommended.
SGLT2 inhibitors	Continue medication regimen unchanged.	No adjustments recommended.	No adjustments recommended.
GLP-1 receptor agonists	Continue medication regimen unchanged.	No adjustments recommended.	No adjustments recommended.
Amylin mimetics	The literature did not provide any precise recommendations concerning adjustments to medication.	No adjustments recommended.	No adjustments recommended.
Insulin glucose lowering agents	Additional adaptations might be required when traversing four or more real-time zones, contingent upon the direction and duration of travel. It’s imperative for individuals with type 1 diabetes to guarantee uninterrupted 24-hour insulin coverage and conduct frequent monitoring of blood glucose levels. If the duration of the journey spans less than 3 days, patients may contemplate adhering to both departure and home schedules throughout the travel period.
Bolus insulin (rapid-acting analogs and short-acting insulin)	Fast-acting insulin formulations are preferred over regular insulin, and pen injectors might be the optimal choice for traveling.	Continue taking the medication without changes. Administer it with meals, ensuring intervals of no less than 3 hours between doses for rapid-acting insulin analogues and 6 hours for regular insulin. Fast-acting insulin analogs might be the preferred option for correcting high glucose levels while traveling.
Basal insulin (intermediate-acting insulin and long-acting basal analogs)	Eastward travel of considerable duration requires a reduction in basal dose. Conversely, long westward travel necessitates either the extension of administration or a supplementary dose. Tactics may involve elongating basal insulin coverage by dividing one standard dose into two separate smaller doses, administering extra basal insulin, or using additional correctional or fast-acting insulin, with or without basal insulin.	As per Pinsker’s guidance, the recalibrated basal dose is computed through a multiplication of the standard dosage by specific factors. When insulin is administered once daily, the dosage is decreased on the day of travel relative to the time of departure. Subsequently, a customary regimen is reinstated in alignment with the time zone of arrival. For individuals administering insulin twice daily, the initial dose postdeparture is diminished and administered based on the departure time. Thereafter, synchronization occurs with the arrival time zone, and the regular dosing schedule resumes. Consistent monitoring of blood glucose levels, especially in relation to the timing of the initial basal insulin dose according to the arrival schedule, can mitigate the risk of hypoglycemia. Furthermore, explicit instructions regarding the correction of hyperglycemia using bolus insulin should be furnished.	When administering insulin once daily, halve the usual dose at the scheduled time based on the departure time. Subsequently, adjust the timepiece to the arrival time zone and administer the second half dose when it’s due, in accordance with the arrival time zone. Proceed with the regular dosing schedule thereafter. For individuals taking insulin twice daily, halve the initial dose encountered during travel at the scheduled time according to the departure time. Then, synchronize the timepiece to the arrival time zone and administer the second half dose when it’s due. Resume the normal dosing schedule thereafter. Ensure clear and comprehensive instructions are provided on correcting hyperglycemia using bolus insulin.
Ultra-long-acting	The literature did not provide any precise recommendations concerning adjustments to medication.	Patients may choose to continue their medication regimen without adjustments, in accordance with the local time zone, as long as the interval between doses on the departure and arrival days exceeds 8 hours. However, if the patient is at heightened risk of hypoglycemia, it is advisable to contemplate reducing the degludec dose by 10–20% on the day of departure.	Patients may continue their medication regimen without adjustments, following the local time zone, as long as the interval between doses on the departure and arrival days is comfortably less than 36 hours.
Premixed	Saskatchewan recommends transitioning to a basal-bolus regimen as preferable.
Insulin pumps	There are conflicting recommendations regarding adjusting basal rates during flight and resetting the clock upon arrival.
Modifying basal insulin rates	There is divergence in advice, with some sources suggesting no alteration in basal rates or providing no specific guidance, whereas others recommend adjusting the rate during the flight and gradually transitioning over time if there is a substantial difference between the basal rates at departure and arrival.	To prepare for travel, it is advised to optimize the patient’s pump settings several weeks in advance. While traveling, it’s recommended to use one of the lower basal insulin rates programmed in the pump until acclimated to the arrival time zone; thereafter, revert to the normal basal rate schedule. Use the bolus calculator/wizard on the pump for administering boluses during meals and for correcting high glucose readings. Regular glucose monitoring is strongly recommended throughout the journey.
Clock calibration	Modify accordingly.	Maintain the pump clock set to the departure time zone throughout the duration of travel. Upon arrival, adjust the pump clock to reflect the local time zone.

CKD, chronic kidney disease; DPP-4, dipeptidyl peptidase 4; GLP-1, glucagon-like peptide-1; SGLT2, sodium glucose cotransporter-2.

Precautions for the accuracy of the blood glucose measurements during flight

Concerns about the accuracy of glucometers in low-pressure cabin environments at high altitudes have received attention. Several publications have meticulously examined the precision of glucometers and implantable subcutaneous glucose sensors in hypobaric settings. These evaluations encompassed a spectrum of enzymatic systems, including methodologies based on hexokinase, glucose dehydrogenase (GDH), and glucose oxidase (GOX). In particular, glucometers that use GOX and GDH enzymes may potentially exhibit an overestimation of glucose values, although GDH meters are generally acknowledged for their higher accuracy. In a study conducted by Fink et al., which evaluated seven commonly used glucometers during mountaineering expeditions, it was found that their performance was influenced by various factors, including elevation, temperature, and relative humidity (Fink et al., 2002). Interestingly, glucometers tended to underestimate glucose levels at higher altitudes. However, conflicting viewpoints persist, some advocating that the margin of error is negligible and others asserting that glucometers remain reliable for decision-making purposes (de Mol et al., 2010; Olateju et al., 2012).

In an evaluation of subcutaneous glucose sensors, a study relied on a GOX enzyme system (Adolfsson et al., 2012). The precision of glucometers appears to be affected by altitude, although there are disparities in the direction of error, either underestimation or overestimation, between different studies and enzymatic systems. A study by Clarke et al. used error grid analysis (EGA) to assess the clinical implications of their findings (Clarke et al., 1987). These analyses revealed that most glucometers operated within EGA-defined “safe zones,” indicating that any inaccuracies in readings at high altitudes would not lead to inappropriate treatment (Giordano et al., 1989; de Mol et al., 2010; Olateju et al., 2012). Despite these reassuring findings, the authors emphasized the importance of patients remaining vigilant about the potential for glucometer inaccuracies in hypobaric conditions.

The growing adoption of continuous glucose monitoring (CGM) systems underscores the need to evaluate both the sensor system and pump functionality under various pressure conditions (Hermanides et al., 2011; Price et al., 1995). Similar to many glucometers, CGM systems commonly use the GOX method. However, it should be noted that the precision and effectiveness of CGM systems are only marginally influenced by hypobaric weather conditions, such as 0.5 and 0.75 atm (Jendle and Adolfsson, 2011). On the other hand, a study conducted under hypobaric conditions found notable discrepancies in glucose input signals at both low and high glucose concentrations (Adolfsson et al., 2012). Consequently, it is prudent to verify CGM readings, as inaccuracies not only influence glucose monitoring but also have implications for the performance of CGM-integrated pumps.

Discussion

General travel guidance has remained relatively consistent, with an increased emphasis on the implementation of airline security protocols. However, strategies for managing and monitoring diabetes among patients are continually advancing, particularly with the advent of novel insulin analogs and medical devices. Although there is alignment in the fundamental principles that govern safe and efficient administration of diabetes medications during travel, specific methodologies for adjusting medication regimens and device usage diverge and are predominantly informed by expert consensus. Despite the concerted effort to mitigate hypoglycemic episodes during travel, the attention given to noninsulin glucose lowering agents in the existing literature is limited. Most publications advocate for the uninterrupted continuation of oral antihyperglycemic agents, despite variations in their mechanisms of action and the recognized risk of hypoglycemia associated with certain agents. However, several references acknowledge the increased risk of hypoglycemia associated with sulfonylureas and recommend omitting a dose during travel or exercising caution about meal skipping and increased physical activity while maintaining the medication regimen (Chandran and Edelman, 2003; Nassar et al., 2012). Certain sources propose that alpha-glucosidase inhibitors, meglitinides, and DPP-4 inhibitors can be continued safely during travel (Aerospace Medical Association Medical Guidelines Task Force, 2003; Chandran and Edelman, 2003; Fatema Jawad, 2016; Frier and Strachan, 2010; Nassar et al., 2012). However, SGLT2 inhibitors, despite their minimal hypoglycemic risk, carry the potential to induce hypotension attributable to their diuretic effects in conjunction with the low humidity and air pressure prevalent in the aircraft cabin environment (Hashiguchi et al., 2013).

The evolution of the insulin analog design, resulting in more predictable and physiologically aligned insulin pharmacokinetic and pharmacodynamic profiles, has significantly facilitated the implementation of flight protocols. Furthermore, advancements in insulin delivery systems, coupled with recent advances in digital technology, offer promising avenues for tailoring insulin administration to individual physiological requirements. The advent of noninvasive glucose monitoring techniques has seen widespread adoption, markedly enhancing the time spent within optimal glucose ranges while reducing the frequency, severity, and duration of hypoglycemic and hyperglycemic episodes. In particular, many pilots now rely on CGM devices in conjunction with the fingerpick blood sampling required during duty periods. It is reasonable to assume that the prevalence of out-of-range glucose levels during flight operations has decreased markedly after the widespread integration and accessibility of CGM systems.

Emphasis on the risk of hypoglycemia has been the main reason for adjusting a diabetes medication regimen. However, other potential side effects, such as dehydration, nausea, vomiting, or diarrhea, which are more commonly associated with the use of newer antihyperglycemic therapies, have not received adequate attention. These adverse reactions should be carefully considered, especially when providing pretravel counseling to patients who intend to travel for long periods or those with a brief history of medication use.

Conclusions

Ensuring safe air travel for people with diabetes requires thorough preparation and adherence to protocols. These include organizing all relevant documentation and prescriptions, stocking sufficient medications and supplies, and maintaining appropriate storage conditions for insulin. Increased vigilance through frequent blood glucose monitoring helps manage glycemic fluctuations and prevent hypoglycemia. Maintaining hydration is essential during air travel, while adjusting medication doses to match flight schedules and mealtimes ensures optimal glycemic control. However, the findings of relevant studies and recommendations vary, are occasionally contradictory or outdated, and often rely on expert opinion or limited observational data. There is a notable absence of robust evidence, especially considering advances in technology and novel diabetes medications. There is an urgent need for well-designed studies to assess the safety and effectiveness of insulin pump and medication adjustments and establish clinical practice standards for people with diabetes traveling by air.

Footnotes

Authors’ Contributions

D.V. reviewed the literature and drafted the first version of the article. G.T., K.A., and V.M. reviewed the literature and created the tables. E.B., M.D., and K.K. reviewed the literature and edited the article. T.K. conceptualized the study, reviewed the literature and edited the article. All authors have read and agreed to the present version of the article.

Author Disclosure Statement

The authors declare that they have no conflict of interest relevant to the publication of this article.

Funding Information

This research received no external funding.

References

Adolfsson

, Örnhagen

, Eriksson

, et al. In-vitro performance of the enlite sensor in various glucose concentrations during hypobaric and hyperbaric conditions. J Diabetes Sci Technol, 2012; 6(6):1375–1382; doi: 10.1177/193229681200600617

Aerospace Medical Association Medical Guidelines Task Force. Medical Guidelines for Airline Travel, 2nd Ed. 2003. Available from: https://pubmed.ncbi.nlm.nih.gov/12817610/ [Last accessed: March 18, 2024].

Alsafadi

, Goodwin

, Syed

. Diabetes care during Hajj. Clin Med (Lond), 2011; 11(3):218–221; doi: 10.7861/CLINMEDICINE.11-3-218

American Diabetes Association. Insulin administration. Diabetes Care, 2004; 27 (Suppl 1):S106–S109; doi: 10.2337/DIACARE.27.2007.S106

Bagshaw

, Illig

. The aircraft cabin environment. Travel Medicine, 2019:429–436; doi: 10.1016/B978-0-323-54696-6.00047-1

Benson

, Metz

. Management of diabetes during intercontinental travel. Bull Mason Clin, 1984:145–151.

Bettes

, McKenas

. Medical Advice for Commercial Air Travelers. 1999. Available from: https://pubmed.ncbi.nlm.nih.gov/10498108/ [Last accessed: March 18, 2024].

Bia

, Barry

. Special health considerations for travelers. Med Clin North Am, 1992; 76(6):1295–1312; doi: 10.1016/S0025-7125(16)30288-7

Brodmann Maeder

, Brugger

, Pun

, et al. The STAR data reporting guidelines for clinical high altitude research. High Alt Med Biol, 2018; 19(1):7–14; doi: 10.1089/HAM.2017.0160

10.

Brubaker

. Adventure travel and type 1 diabetes: The complicating effects of high altitude. Diabetes Care, 2005; 28(10):2563–2572; doi: 10.2337/DIACARE.28.10.2563

11.

Burnett

JCD

. Long- and short-haul travel by air: Issues for people with diabetes on insulin. J Travel Med, 2006; 13(5):255–260; doi: 10.1111/J.1708-8305.2006.00057.X

12.

Canadian Paediatric Society. Air travel and children’s health issues. Paediatr Child Health, 2007; 12(1):45–59; doi: 10.1093/PCH/12.1.45

13.

Centers for Disease Control and Prevention. Long-Term Trends in Diabetes. 2017.

14.

Chandran

, Edelman

. Have insulin, will fly: Diabetes management during air travel and time zone adjustment strategies. Clinical Diabetes, 2003; 21(2):82–85; doi: 10.2337/DIACLIN.21.2.82

15.

Chełmińska

BJ K

. Travelling Diabetics—PubMed. 2002. Available from: https://pubmed.ncbi.nlm.nih.gov/12608590/ [Last accessed: March 17, 2024].

16.

Clarke

, Cox

, Gonder-Frederick

, et al. Evaluating clinical accuracy of systems for self-monitoring of blood glucose. Diabetes Care, 1987; 10(5):622–628; doi: 10.2337/DIACARE.10.5.622

17.

Cradock

. The Traveller with Diabetes: Answers to Common Queries. 1997. Available from: https://pubmed.ncbi.nlm.nih.gov/9451142/ [Last accessed: March 18, 2024].

18.

Cross

, Jenkins

, Neal

, et al. Travelling with an insulin pump. Infu System Asia, 2008:9–14.

19.

de Mol

, Krabbe

, de Vries

, et al. Accuracy of handheld blood glucose meters at high altitude. PLoS One, 2010; 5(11):e15485; doi: 10.1371/JOURNAL.PONE.0015485

20.

Dewey

, Riley

. Have diabetes, will travel. Postgrad Med, 1999; 105(2):111–126; doi: 10.3810/PGM.1999.02.538

21.

Driessen

, Cobelens

FGJ

, Ligthelm

. Travel-related morbidity in travelers with insulin-dependent diabetes mellitus. J Travel Med, 1999; 6(1):12–15; doi: 10.2310/7060.1999.00004

22.

Dunning

. Diabetes Now–Safe Travel Tips for the Diabetic Patient (Continuing Education Credit)—PubMed. 1989. Available from: https://pubmed.ncbi.nlm.nih.gov/2648549/ [Last accessed: March 17, 2024].

23.

Elfrink

, Van Den Hoek

, Sonder

GJB

. Trends and characteristics among HIV-infected and diabetic travelers seeking pre-travel advice. Travel Med Infect Dis, 2014; 12(1):79–83; doi: 10.1016/J.TMAID.2013.06.009

24.

Ericsson

. Travellers with pre-existing medical conditions. Int J Antimicrob Agents, 2003; 21(2):181–188; doi: 10.1016/S0924-8579(02)00288-1

25.

Fink

, Christensen

, Ellsworth

. Effect of high altitude on blood glucose meter performance. Diabetes Technol Ther, 2002; 4(5):627–635; doi: 10.1089/152091502320798259

26.

Frier

, Strachan

MWJ

. 24 Social Aspects of Diabetes. 2010.

27.

Gill

, Redmond

. Insulin treatment, time-zones and air travel: A survey of current advice from british diabetic clinics. Diabet Med, 1993; 10(8):764–767; doi: 10.1111/J.1464-5491.1993.TB00161.X

28.

Giordano

, Thrash

, Hollenbaugh

, et al. Performance of seven blood glucose testing systems at high altitude. Diabetes Educ, 1989; 15(5):444–448; doi: 10.1177/014572178901500515

29.

Handbook of Civil Aviation Medical Examiners-TP 13312. Canadian Guidelines for the Assessment of the Medical Fitness in Pilots, Flight Engineers and Air Traffic Controllers, with Diabetes Mellitus. 2024. Available from: https://tc.canada.ca/en/aviation/publications/handbook-civil-aviation-medical-examiners-tp-13312 [Last accessed: February 16, 2024].

30.

Hashiguchi

, Takeda

, Yasuyama

, et al. Effects of 6-h exposure to low relative humidity and low air pressure on body fluid loss and blood viscosity. Indoor Air, 2013; 23(5):430–436; doi: 10.1111/INA.12039

31.

Hermanides

, Nørgaard

, Bruttomesso

, et al. Sensor-augmented pump therapy lowers HbA(1c) in suboptimally controlled type 1 diabetes; A randomized controlled trial. Diabet Med, 2011; 28(10):1158–1167; doi: 10.1111/J.1464-5491.2011.03256.X

32.

Høi-Hansen

, Pedersen-Bjergaard

, Thorsteinsson

. Classification of hypoglycemia awareness in people with type 1 diabetes in clinical practice. J Diabetes Complications, 2010; 24(6):392–397; doi: 10.1016/J.JDIACOMP.2009.07.006

33.

Holmwood

, Phillips

. Common Dilemmas in Diabetic Care. 1997. Available from: https://pubmed.ncbi.nlm.nih.gov/9115109/ [Last accessed: March 18, 2024].

34.

ICAO. ICAO Doc 8984 Manual of Civil Aviation Medicine—Third Edition 2012 | SKYbrary Aviation Safety. 2024. Available from: https://skybrary.aero/bookshelf/icao-doc-8984-manual-civil-aviation-medicine-third-edition-2012 [Last accessed: March 17, 2024].

35.

Inkster

, Frier

. Diabetes and driving. Diabetes Obes Metab, 2013; 15(9):775–783; doi: 10.1111/DOM.12071

36.

International Diabetes Federation. International Charter of Rights and Responsibilities. 2012. Available from: https://d-net.idf.org/en/library/206-international-charter-of-rights-and-responsibilities.html [Last accessed: February 16, 2024].

37.

Izadi

, Hosseini

, Pazham

. Travel guidance for people with diabetes; A narrative review. Int J Travel Med Glob Health, 2015; 3(4):143–147; doi: 10.20286/IJTMGH-0304128

38.

Jawad

FSK

. Diabetes and Travel—PubMed. 2016. Available from: https://pubmed.ncbi.nlm.nih.gov/27686320/ [Last accessed: March 18, 2024].

39.

Jendle

, Adolfsson

. Impact of high altitudes on glucose control. J Diabetes Sci Technol, 2011; 5(6):1621–1622; doi: 10.1177/193229681100500642doi: 101177/193229681100500642

40.

Jones

, Platts

, Harvey

, et al. An effective insulin regimen for long distance air travel. Pract Diab Int, 1994; 11(4):157–158; doi: 10.1002/PDI.1960110407

41.

Jornsay

DL LD

. Diabetes and the Traveller. Clin Diabetes, 1998:525–555.

42.

Josse

, Woo

. Flexibly timed once-daily dosing with degludec: A new ultra-long-acting basal insulin. Diabetes Obes Metab, 2013; 15(12):1077–1084; doi: 10.1111/DOM.12114

43.

Kaplan

, Palmer

, Nassar

, et al. Southwestern internal medicine conference. Keeping travelers healthy. Am J Med Sci, 1998; 315(5):327–336; doi: 10.1097/00000441-199805000-00009

44.

King

, Goss

, Paterson

, et al. Changes in altitude cause unintended insulin delivery from insulin pumps: Mechanisms and implications. Diabetes Care, 2011; 34(9):1932–1933; doi: 10.2337/DC11-0139

45.

Koufakis

, Karras

, Mustafa

, et al. The effects of high altitude on glucose homeostasis, metabolic control, and other diabetes-related parameters: From animal studies to real life. High Alt Med Biol, 2019; 20(1):1–11; doi: 10.1089/HAM.2018.0076

46.

Larsen

, Hansen

, Olsen

, et al. The effect of altitude hypoxia on glucose homeostasis in men. J Physiol, 1997; 504(Pt 1):241–249; doi: 10.1111/J.1469-7793.1997.241BF.X

47.

Levy-Shraga

, Hamiel

, Yaron

, et al. Health risks of young adult travelers with type 1 diabetes. J Travel Med, 2014; 21(6):391–396; doi: 10.1111/JTM.12136

48.

MacDonald

. Routine Management and Special Problems of Diabetic Children—PubMed. 1983. Available from: https://pubmed.ncbi.nlm.nih.gov/6371862/ [Last accessed: March 17, 2024].

49.

MacNeill

, Fredericks

. Vacation ease: Travelling with an insulin pump. Can J Diabetes, 2015; 39(3):178–182; doi: 10.1016/J.JCJD.2015.02.004

50.

McCarthy

. Travelers with Pre-Existing Disease. In: ( Keystone

, Kozarsky

, Freedman

., Eds.) Travel Medicine. 2004. Available from: https://www.proquest.com/docview/201568018?sourcetype=Scholarly%20Journals [Last accessed: March 17, 2024].

51.

Mileno

, Bia

. The compromised traveler. Infect Dis Clin North Am, 1998; 12(2):369–412; doi: 10.1016/S0891-5520(05)70010-6

52.

Mills

, Harding

. Fitness to travel by air. II: Specific medical considerations. Br Med J (Clin Res Ed), 1983; 286(6374):1340–1341; doi: 10.1136/BMJ.286.6374.1340

53.

Mitchell

, Hine

, Vening

, et al. A UK civil aviation authority protocol to allow pilots with insulin-treated diabetes to fly commercial aircraft. Lancet Diabetes Endocrinol, 2017; 5(9):677–679; doi: 10.1016/S2213-8587(17)30264-4

54.

Moran

, Burson

. How to enjoy the holidays with diabetes. Home Healthc Nurse, 2014; 32(10):610–611; doi: 10.1097/NHH.0000000000000158

55.

Nassar

, Cook

, Edelman

. Diabetes management during travel management perspective. Management PerSPective Nassar, Cook & Edelman. Diabetes Manage, 2012; 2(3):205–212; doi: 10.2217/DMT.12.23

56.

O W Skjenna

, Evans

, Moore , et al. Helping Patients Travel by Air. 1991. Available from: https://pubmed.ncbi.nlm.nih.gov/1989707/ [Last accessed: March 18, 2024].

57.

Olateju

, Begley

, Flanagan

, et al. Effects of simulated altitude on blood glucose meter performance: Implications for in-flight blood glucose monitoring. J Diabetes Sci Technol, 2012; 6(4):867–874; doi: 10.1177/193229681200600418

58.

Patterson Tfpfjbmb

. Assuring Safe Travel for Today’s Elderly—PubMed. 1989. Available from: https://pubmed.ncbi.nlm.nih.gov/2676733/ [Last accessed: March 17, 2024].

59.

Pray

. The diabetic traveller: How to avoid problems. J Mod Pharm, 1996.

60.

Price

Jr , Hammett-Stabler

, Kemper

, et al. Evaluation of Glucose Monitoring Devices in the Hyperbaric Chamber. 1995. Available from: https://pubmed.ncbi.nlm.nih.gov/7783938/ [Last accessed: March 18, 2024].

61.

Ross

. Diabetes and Travel. 1985. Available from: https://pubmed.ncbi.nlm.nih.gov/21274129/ [Last accessed: March 17, 2024].

62.

Rostrup

. Catecholamines, hypoxia and high altitude. Acta Physiol Scand, 1998; 162(3):389–399; doi: 10.1046/J.1365-201X.1998.00335.X

63.

Saskatchewan health. Saskatchewan Advanced Insulin Dose Adjustment Module. 2010. Available from: https://docplayer.net/6461400-Saskatchewan-insulin-adjustment-module-page-2-may-2010.html [Last accessed: March 17, 2024].

64.

Sawhney

, Malhotra

, Singh

, et al. Insulin secretion at high altitude in man. Int J Biometeorol, 1986; 30(3):231–238; doi: 10.1007/BF02189466

65.

Shand

. The assessment of fitness to travel. Occup Med (Lond), 2000; 50(8):566–571; doi: 10.1093/OCCMED/50.8.566

66.

Sharma

, Akre

, Chakole

, et al. Stress-induced diabetes: A review. Cureus, 2022; 14(9):e29142; doi: 10.7759/CUREUS.29142

67.

Simons

, Koopman

, Osinga

. Would you fly with a pilot on insulin? Lancet Diabetes Endocrinol, 2014; 2(6):446–447; doi: 10.1016/S2213-8587(13)70197-9

68.

Stock

, Chapman

, Stirling

, et al. Effects of exercise, altitude, and food on blood hormone and metabolite levels. J Appl Physiol Respir Environ Exerc Physiol, 1978; 45(3):350–354; doi: 10.1152/JAPPL.1978.45.3.350

69.

Suh

, Mileno

. Challenging scenarios in a travel clinic: Advising the complex traveler. Infect Dis Clin North Am, 2005; 19(1):15–47; doi: 10.1016/J.IDC.2004.10.004

70.

Sullivan

. Travel with chronic medical conditions. The Travel and Tropical Medicine Manual, 2016:228–242; doi: 10.1016/B978-0-323-37506-1.00016-7Fifth Edition

71.

Thomas

. Preparing Patients to Travel Abroad Safely. Part 1: Taking a Travel History and Identifying Special Risks—PubMed. 2000. Available from: https://pubmed.ncbi.nlm.nih.gov/10660795/ [Last accessed: March 17, 2024].

72.

Thomas Sr

. The Endocrine System. ( Hornbein

and Schoene

. eds.) High Altitude: An Exploration of Human Adaptation, 2001; 601–644; doi: 10.3109/9780203908044

73.

Transcend Glucose Gels/Travelling With Diabetes/Flying With Diabetes. 35 Top Tips for Travelling with Diabetes. 2017. Available from: https://transcendfoods.com/blog/35-top-tips-for-travel-with-diabetes [Last accessed: February 16, 2024].

74.

UK CAA. Physiology of Flight | Civil Aviation Authority. 2024. Available from: https://www.caa.co.uk/passengers/before-you-fly/am-i-fit-to-fly/guidance-for-health-professionals/physiology-of-flight/ [Last accessed: February 16, 2024].

75.

UK Civil Aviation Authority. UK CAA Policy for the Medical Certification of Pilots and ATCOs with Diabetes. 2018. Available from: https://www.caa.co.uk/aeromedical-examiners/medical-standards/pilots/conditions/metabolic-and-endocrinology/metabolic-and-endocrinology-guidance-material-gm/ [Last accessed: February 16, 2024].

76.

Voss

. Air Travel for the Chronically Ill and the Elderly. 1983. Available from: https://pubmed.ncbi.nlm.nih.gov/6219564/ [Last accessed: March 18, 2024].

77.

Walker

, Williams

. Diabetics, children, and pregnant women. Br Med J (Clin Res Ed), 1983; 286(6374):1337–1339; doi: 10.1136/BMJ.286.6374.1337

78.

Wientjens

, Cairns

. Fighting discrimination. Diabetes Res Clin Pract, 2012; 98(1):33–37; doi: 10.1016/J.DIABRES.2012.05.021

79.

Woolcott

, Ader

, Bergman

. Glucose homeostasis during short-term and prolonged exposure to high altitudes. Endocr Rev, 2015; 36(2):149–173; doi: 10.1210/ER.2014-1063