Editorial: High Altitude Medicine and Biology in Peru

The VIII World Congress on High Altitude Medicine and Physiology was held in Arequipa, Peru, from August 8 to 12 of this year and the abstracts of the meeting are contained in this issue. This provides an opportunity to briefly discuss some of the high points of high altitude research in this important country.

Sightings Edited by John W. Severinghaus (p. 177)

High Altitude Web Edited by Thomas E. Dietz (p. 181)

Clinician's Corner Edited by Andrew Luks

“Can patients with coronary heart disease go to high altitude?”

Increasingly, patients with a history of coronary heart disease wish to go to high altitude and deciding on the appropriate advice is sometimes difficult. Dehnert and Bärtsch (p. 183) discuss this important problem.

SCIENTIFIC PAPERS

Altitude Illness in Qinghai-Tibet Railroad Passengers

There have been a number of previous references in this Journal to the Qinghai-Tibet railroad that reaches an altitude of 5000 m and spends several hours above 4500 m. Each passenger car is provided with an oxygen generator and the oxygen concentration in the air can be raised to as high as 25%. Tian-Yi Wu and collaborators (p. 189) now report on the incidence of altitude illness in the train. Seventy-eight percent of the passengers studied reported symptoms of high-altitude illness and 24% developed Acute Mountain Sickness. The incidence was particularly high in Han lowlanders, but zero in Tibetans. Most cases of AMS were mild, but a few necessitated medical attention.

Hematological and Physiological Adaptations Following 46 Weeks of Moderate Altitude Residence

Brothers and colleagues (p. 199) studied cadets at the US Air Force Academy in Colorado Springs, altitude 2210 m. This is a useful study because relatively little is known about acclimatization to moderate altitudes like this. Hematological differences included significantly higher hemoglobin concentrations, hematocrits and serum ferritin levels than in sea-level controls. There were also differences in physical performance with sea-level controls having lower maximal oxygen consumptions, slower run times, and lower physical fitness scores.

The Physiological Basis of Reduced VO2 max in Operation Everest II

A frequently asked question is what limits maximal oxygen consumption with increasing altitude. Wagner (p. 209) analyzed data from the low pressure chamber study Operation Everest II and concluded that diffusion limitation in both the lungs and muscles explains most of the reduced performance, while changes in the convective processes of ventilation and blood flow contribute little or no impediment to oxygen transport.

Incidence and Predictors of Acute Mountain Sickness among Trekkers on Mount Kilimanjaro

Very large numbers of trekkers attempt to ascend Mt. Kilamanjaro, altitude 5895 m, and many do this within a few days. Jackson and coworkers (p. 217) studied trekkers using various routes on the mountain and confirmed previous work showing that the incidence of Acute Mountain Sickness is high. For example, at an altitude of 4730 m, 47% of climbers from all itineraries had AMS. Interestingly, the incidence of AMS was not significantly reduced either by taking acetazolamide, or having a rest day at an altitude of 3700 m.

Demographic, Geographic, and Expedition Determinants of Reaching the Summit of Denali

Mt. McKinley (Denali) at an altitude of 6194 m is the highest mountain in North America and attracts thousands of climbers. McIntosh and colleagues (p. 223) carried out a retrospective analysis of 21,809 climbers of whom 51.8% reached the summit. Male climbers were more likely to succeed than females, climbers over 40 years old were less successful than younger people, and, interestingly, climbers from outside North America had better odds of achieving success.

Role of Oxidative Stress and Inflammation in Hypoxia-Induced Cerebral Edema: a Molecular Approach

The pathogenesis of High Altitude Cerebral Edema is not fully understood. Kumari and coworkers (p. 231) studied the possible role of oxidative stress and inflammation in rats exposed to a simulated altitude of 7620 m (25,000 ft) for periods of up to 48 hours. It was found that the maximum increase in brain water content occurred at 24 hours of exposure and this was accompanied by a significant increase in reactive oxygen species. An increase in pro-inflammatory cytokines was also observed and the authors concluded that inflammation plays a significant role in hypoxia-induced cerebral edema.

Abstracts of the VIII World Congress on High Altitude Medicine and Physiology

These were available at the meeting in August and are published here to provide a permanent record.