Pranic Meditation Affects Phagocyte Functions and Hormonal Levels of Recent Practitioners

Abstract

Objectives:

Despite the recognized importance of phagocytes in the maintenance and recovery of health, the influence of meditation on their functions is not properly established. This investigation aimed at evaluating the influence of pranic meditation on the functions of phagocytes, and on the levels of hormones that influence them.

Design:

A pre–post design was adopted.

Setting:

The investigation was carried out at a university research laboratory.

Subjects and methods:

Twenty-nine (29) healthy individuals of both sexes, 24–67 years old (median 45), with no previous experience in meditation, received 3-hour-duration weekly training on pranic meditation during 10 weeks and agreed to engage in daily home practice for 20 minutes. Pranic meditation is a novel method of meditation, based on the Vedic tradition, which uses techniques of breathing and visualization for quieting the mind, and for capturing and intentionally directing prana (“vital energy”) wherever necessary. For assessing phagocytosis, the production of hydrogen peroxide and nitric oxide by monocytes, and the concentrations of corticotrophin and cortisol, blood was collected at the beginning (week 1), at the middle (week 5), and by the end (week 10) of the practice period. At the same intervals, melatonin concentrations were evaluated in the saliva.

Results:

Those who meditated for more than 980 minutes showed increased phagocytosis, their monocytes produced higher concentrations of hydrogen peroxide, and their plasma levels of corticotrophin were reduced. The production of nitric oxide by monocytes, and the levels of cortisol and melatonin were not modified by meditation.

Conclusions:

This is the first study to show that a short program of pranic meditation practice was able to upregulate the function and metabolism of phagocytes, in parallel with the reduction of the plasma levels of corticotrophin. The results of this study point to a possible causal effect between these events, and indicate that pranic meditation could be useful for stimulating the function and metabolism of phagocytes.

Introduction

P ranic meditation is a novel method of meditation, based on the Vedic tradition and developed by one of the authors (CET), which uses techniques of breathing and visualization for quieting the mind, and for capturing and directing prana to selected targets according to the intention. The concept of prana comes from the Vedic and Vedantic philosophies that consider it as the vital force of all living beings and, following Indian traditional medicine, that health depends on its balance.^1,2 Prana is also known as qi in Traditional Chinese Medicine, ki in Japanese traditional medicine,³ and as biofield⁴ or subtle energy⁵ by Western researchers. However, these “forces” do not act as typical physical energies; since they are not limited by space,⁶ they are able to cross electromagnetic shields,⁷ and are influenced by the intention of the emitter.^8,9 Therefore, the authors coined the term metenergy [met(a)=beyond+energy] and will use it hereafter to encompass these forces that affect human beings,^10,11 animals,^12,13 cells,^14,15 molecules,^16,17 and atoms,^18,19 and whose properties are different from those of the four recognized physical forces—electromagnetic, gravitational, and strong and weak atomic forces.²⁰

Courses for training on pranic meditation have been regularly offered to the community and, as a complementary therapy, to individuals with cancer and other chronic diseases, since 2007 in Brazilian health and academic institutions. The now over 600 practitioners have often received a great deal of benefits on their physical, mental/emotional, interpersonal and spiritual health, together with an increased feeling of vigor, serenity, intuition, and compassion. These very favorable results prompted the authors to investigate the possible mechanisms involved in the health-promoting effects of pranic meditation, including those associated with phagocyte functions, and the levels of hormones involved in the control of the activity of these cells.

Phagocytes are recognized as major components of the immune system due to their ability to detect, ingest, and destroy potentially dangerous elements such as infectious agents and cancer cells, to present them as antigens to lymphocytes, and to induce and regulate the immune response.^21,22 Deficiency of phagocyte functions may result in increased susceptibility to infections and cancer.^23,24 Phagocytes also act as a link between immune and neuroendocrine systems,^25,26 and influence and are influenced by the hypothalamic–pituitary–adrenal (HPA) axis.^27,28 Corticotrophin and cortisol hormones released from an activated HPA axis are reported to downmodulate the immune response,²⁹ and therefore, to disrupt homeostasis and increase the susceptibility to diseases. Melatonin, the hormone produced by the pineal gland, on the other hand, has been considered to upmodulate the immune system, stimulate phagocytosis,³⁰ and affect the production of cytokines by human monocytes.³¹

The present investigation aimed at establishing the possible role of pranic meditation on the function of blood phagocytes and on the levels of the hormones capable of influencing them.

Materials and Methods

Subjects

A total of 29 healthy individuals of both sexes, 24–67 years old (median 45), who attended a 10-week training course on pranic meditation volunteered to participate in the investigation. They had no previous experience with meditation, and were not taking any drug capable of affecting the immune or the endocrine systems.

This investigation was previously approved by the Committee on Ethics of Human Experiments of the Faculty of Medicine, University of Brasilia, and informed consents were obtained from all participants.

Pranic meditation training

The participants of the research were submitted to a training course on pranic meditation of 3-hour weekly classes consisting of an exposition on the theoretical grounds of the method, followed by collective meditation practice. The practitioners were encouraged to engage in daily individual practices of 20 minutes at home, and to fill a “practice diary” noting down the frequency, duration, and feelings associated with the meditation practices.

The following subjects were discussed during the 10-week training course by a qualified instructor, with over 20 years of practice experience: (1) What is meditation; (2) The healing power of meditation; (3) Pranic meditation; (4) Prana and pranayama; (5) The chakra system: anatomy and physiology; (6) The chakra system: pathology; (7) Mantra; (8) Obstacles and risks of meditation; (9) Pranic meditation: health and equilibrium; (10) Meditation and transcendence. The practices consisted of the following exercises: (1) Visualization of the blue wave of peace: a visualization technique for quieting the mind and relaxing body; (2) Pranayama 1: a technique of conscious breathing aimed at quieting the mind and capturing prana; (3) Pranayama 2: a technique of conscious breathing with prolonged interruptions of the air flow for prana capture and absorption; (4) Pranification of the chakras: a visualization technique in which each one of the seven main chakras are activated by directing prana and mantra to them, following by prana circulation throughout the chakra system; (5) Pranic vitalization: a visualization technique for directing prana wherever necessary in the body; (6) Pranic emission: a visualization technique for directing prana to someone else; (7) Deep meditation: a technique of thorough quieting of the mind for attaining transcendence.

Experimental design

On the 1st, 5th, and 10th weeks of pranic meditation practice blood samples were collected from the volunteers to assess phagocytosis, production of hydrogen peroxide and nitric oxide by monocytes, and to evaluate the concentrations of corticotrophin and cortisol. At the same time intervals, saliva samples were collected for the quantification of melatonin. The study group was stratified according to the time dedicated to meditation throughout the 10 weeks of training into “higher practitioners” (higher than 980 minutes of meditation, n=22) and “lower practitioners” (980 minutes or less of meditation, n=7).

Blood and saliva samples

Venous blood samples were collected from the practitioners at the research laboratory between 8:00 and 8:30 am, after a period of rest, according to the recommendations of the Clinical and Laboratory Standards Institute, either into heparinized Vacutainer tubes (assessment of hydrogen peroxide and nitric oxide production by monocytes, and quantification of the plasma levels of corticotrophin and cortisol), or into those without anticoagulant (assessment of phagocytosis by neutrophils and monocytes). Plasma samples were kept frozen at −80°C until quantifications of corticotrophin and cortisol were carried out, whereas the evaluation of phagocytosis and the assessment of hydrogen peroxide and nitric oxide production by monocytes were immediately performed.

Salivary samples were collected by the volunteers at home into sterile plastic tubes using a straw at 3:00 am, after receiving instructions on how to induce salivation, collect the saliva, register the time of collection, and store and transport the material to the laboratory. Saliva samples were kept frozen at −80°C until quantification of melatonin was carried out.

Isolation of blood mononuclear cells

Mononuclear cells were collected by centrifugation through a cushion of Percoll, density 1.077 g/mL at 750g, twice washed by centrifugation in cold RPMI 1640 medium, pH 7.2, supplemented with 20 mmol/L HEPES, 2 mmol/L glutamine, and 2.5 mg/dL gentamicin. Afterwards, cell suspensions were prepared in RPMI 1640 medium for the evaluation of the production of hydrogen peroxidase and nitric oxide by monocytes.

Assessment of hydrogen peroxide production by monocytes

Hydrogen peroxide production by monocytes was assessed according to the method described by Pick.³² In brief, triplicate samples of 1.5×10⁵ mononuclear cells in RPMI 1640 medium were distributed into 96-well plastic microplates and incubated with a solution containing phenol red and horseradish peroxidase type I, with or without stimulation with phorbol myristate acetate. After 60 minutes incubation at 37°C in a wet chamber with a mixture of atmospheric air plus 15% CO₂, absorbance was read on a microplate spectrophotometer (Spectramax Plus) at 620 nm.

Assessment of nitric oxide production by monocytes

Nitric oxide production by monocytes was assessed according to the method described by Green et al.³³ In brief, triplicate samples of 1.5×10⁵ mononuclear cells in RPMI 1640 medium were distributed into 96-well plastic microplates and incubated for 24 hours at 37°C, with or without lipopolysaccharide of Escherichia coli 055:b5, in a wet chamber with a mixture of atmospheric air plus 15% CO₂. Supernatants were transferred to another microplate and Greiss reagent (0.2% N-(1-naphthyl) ethylene diamine plus 2% sulphanilamide solution in RPMI 1640 medium) was added. The absorbance was read on a microplate spectrophotometer (Spectramax Plus) at 590 nm.

Assessment of phagocytosis

The phagocytic capacity of blood phagocytes (neutrophils+monocytes) was assessed by an adaptation of the technique previously described by Muniz-Junqueira et al.³⁴ In brief, samples of whole blood were distributed on round glass coverslips (13-mm diameter) placed into the wells of 24-well microplates. After incubation at 37°C for 45 minutes, coverslips were rinsed with 0.15 mol/L phosphate-buffered saline, pH 7.2, and the adherent phagocytes were incubated for 30 minutes with a suspension of yeast cells (Saccharomyces cerevisiae) at 37°C in a wet chamber with a mixture of atmospheric air plus 15% CO₂. Afterwards, coverslips were rinsed with 0.15 mol/L phosphate-buffered saline pH 7.2, stained with Giemsa solution, and blindly evaluated by microscopy. The phagocytic index was calculated by the percentage of phagocytes involved in phagocytosis×the mean of yeast cells ingested per phagocyte.

Determination of plasma concentrations of corticotrophin and cortisol

Corticotrophin and cortisol levels were determined by a competitive chemoluminescence immunometric solid-phase assay, using the Immulite Immunoassay System 2000 (Siemens, USA). The samples were processed according to the manufacturer's instructions.

Determination of the salivary concentrations of melatonin

Melatonin concentrations were determined by radioimmunoassay using the kit of Melatonin Research RIA KIPL 3900 (BioSource, Nivelles, Belgium). The samples were processed according to the manufacturer's instructions.

Statistical analysis

The Prism Graph Pad software package, version 5.0, for Windows was used for performing the statistical analyses and preparing the graphics. Data were analyzed by the Friedman's test, followed by the Dunn's method for multiple comparisons.

Results

The data showed that pranic meditation increased phagocytosis by blood neutrophils and monocytes in “higher practitioners” (higher than 980 minutes of meditation; p=0.01) (Fig. 1A), but not in “lower practitioners” (980 minutes or less of meditation; p=0.08) (Fig. 1B).

FIG. 1.

A. Effect of pranic meditation on the phagocytic capacity of blood phagocytes of healthy “higher practitioners” (higher than 980 minutes of practice) (n=14). The data are expressed as median (solid line in each box), quartiles (the tops and bottoms of each box), and minimum and maximum values (bars). A significant increase of phagocytosis was detected when pre-intervention (week 1) was compared to postintervention (week 10) values (p=0.01, Friedman's test followed by Dunn's method for multiple comparisons). B. Effect of pranic meditation on the phagocytic capacity of blood phagocytes of healthy “lower practitioners” (980 minutes or less of practice) (n=7). The data are expressed as median (solid line in each box), quartiles (the tops and bottoms of each box), and minimum and maximum values (bars). No significant change in phagocytosis was detected when pre- and postintervention values were compared (p=0.08, Friedman's test followed by Dunn's method for multiple comparisons).

The increase of phagocytosis paralleled the rise of the oxidative metabolism of monocytes. The production of hydrogen peroxide by monocytes, an important step in the processing of ingested materials by phagocytes, was increased in the higher (p<0.0001) (Fig. 2A), but not in the lower practitioners (p=0.48) (Fig. 2B).

FIG. 2.

A. Effect of pranic meditation on hydrogen peroxide production by monocytes of healthy “higher practitioners” (higher than 980 minutes of practice) (n=22). The data are expressed as median (solid line in each box), quartiles (the tops and bottoms of each box), and minimum and maximum values (bars). The hydrogen peroxide production increased when pre-intervention (week 1) and the middle (week 5) were compared to postintervention (week 10) (p<0.0001, Friedman's test followed by Dunn's method for multiple comparisons). B. Effect of pranic meditation on hydrogen peroxide production by monocytes of healthy “lower practitioners” (980 minutes or less of practice) (n=7). The data are expressed as median (solid line in each box), quartiles (the tops and bottoms of each box), and minimum and maximum values (bars). No significant change in hydrogen peroxide production was detected when pre- and postintervention values were compared (p=0.48, Friedman's test followed by Dunn's method for multiple comparisons).

The production of nitric oxide, a second oxidative metabolite of monocytes that also takes part in the process of phagocytosis, showed no modification both in the higher practitioners (p=0.24) (Fig. 3A), and in the lower practitioners (p=0.36) (Fig. 3B).

FIG. 3.

A. Effect of pranic meditation on nitric oxide production by monocytes of healthy “higher practitioners” (higher than 980 minutes of practice) (n=22). The data are expressed as median and extreme values. No statistical significance was detected from pre-intervention (week 1) to postintervention (week 10) (p=0.24, Friedman's test followed by Dunn's method for multiple comparisons). B. Effect of pranic meditation on nitric oxide production by monocytes of healthy “lower practitioners” (980 minutes or less of practice) (n=5). The data are expressed as median and extreme values. No significant change in nitric oxide production was detected when pre- and postintervention values were compared (p=0.36, Friedman's test followed by Dunn's method for multiple comparisons).

Corticotrophin, the hormone produced by the pituitary gland that induces the production of adrenal cortisol, had its blood level decreased in the higher practitioners (p=0.002) (Fig. 4A), but not in the lower practitioners (p=0.76) (Fig. 4B).

FIG. 4.

A. Effect of pranic meditation on the plasma levels of corticotrophin of healthy “higher practitioners” (higher than 980 minutes of practice) (n=22). The data are expressed as median and extreme values. The corticotrophin levels decreased from pre-intervention (week 1) to postintervention (week 10) (p=0.002, Friedman's test followed by Dunn's method for multiple comparisons). B. Effect of pranic meditation on the plasma levels of corticotrophin of healthy “lower practitioners” (980 minutes or less of practice) (A, n=7), and “less assiduous practitioners” (70% or less of assiduity to meditation classes) (B, n=7). The data are expressed as median and extreme values. No significant change in corticotrophin levels was detected when pre- and postintervention values were compared (p=0.76, Friedman's test followed by Dunn's method for multiple comparisons).

No statistical difference between the pre- and postintervention levels of cortisol was detected both in the higher practitioners (p=0.95) (Fig. 5A) and in the lower practitioners (p=0.77) (Fig. 5B).

FIG. 5.

A. Effect of pranic meditation on the plasma levels of cortisol of healthy “higher practitioners” (higher than 980 minutes of practice) (n=22). The data are expressed as median (solid line in each box), quartiles (the tops and bottoms of each box), and minimum and maximum values (bars). No significant changes in cortisol levels were detected when pre- and postintervention values were compared (p=0.95, Friedman's test followed by Dunn's method for multiple comparisons). B. Effect of pranic meditation on plasma levels of cortisol of healthy “lower practitioners” (980 minutes or less of practice) (n=7). The data are expressed as median (solid line in each box), quartiles (the tops and bottoms of each box), and minimum and maximum values (bars). No significant change in cortisol levels was detected when pre- and postintervention values were compared (p=0.77, Friedman's test followed by Dunn's method for multiple comparisons).

The levels of salivary melatonin were not modified by pranic meditation, due to the great individual variation of the hormone levels observed (p=0.54) (Fig 6).

FIG. 6.

Effects of pranic meditation on the salivary levels of melatonin of healthy “higher practitioners” (higher than 980 minutes of practice) (n=22). The data are expressed as median (solid line in each box), quartiles (the tops and bottoms of each box), and minimum and maximum values (bars). No significant change in melatonin was detected when pre- and postintervention values were compared (p=0.54, Friedman's test followed by Dunn's method for multiple comparisons).

Discussion

The present investigation is the first to demonstrate that a 10-week program of pranic meditation practices was capable of affecting the immune and the endocrine systems of recent practitioners with no previous meditation experience. These data showed a significant stimulatory effect of meditation on phagocytosis and hydrogen peroxide production by blood monocytes when pre- and postintervention levels were compared. It was also observed that the plasma levels of corticotrophin of the higher practitioners were reduced by the end of the training period, suggesting a possible effect of meditation on the downmodulation of the hypothalamic–pituitary–adrenal axis activity. No statistical differences between the pre- and postintervention levels of cortisol and melatonin as well as of the nitric oxide production by monocytes were detected, probably due to the intense individual variation.

The crucial role played by phagocytes in the detection and destruction of infectious agents,³⁵ apoptotic cells,³⁶ and cancer cells³⁷ as well as in the regulation of inflammation³⁸ and the neuroendocrine system³⁹ has been well recognized. In spite of this relevance, little attention has been addressed to the effect of meditation on phagocyte functions. Some data are available on the effect of qigong. This modality, originated from the ancient Traditional Chinese Medicine, consists basically of practices of physical movements, breathing exercises, and meditation aimed at improving self-regulation and health.⁴⁰ In common with pranic meditation, qigong practices involve techniques of capture and distribution of metenergy (see Introduction). It has been reported that qigong practitioners present an increase of neutrophil phagocytosis⁴¹ as well as of production of superoxide anion (O₂ ^-), a microbicidal reactive oxygen intermediate, by neutrophils.⁴²

It has been considered that meditation downmodulates the hypothalamic–pituitary–adrenal axis⁴³ and, therefore, decreases the levels of corticotrophin⁴⁴ and cortisol.⁴⁵ The data in the present study suggest that this could also be the case for pranic meditation, since it was found that the group of higher practitioners, but not the lower ones, showed reduced plasma levels of corticotrophin, although the levels of cortisol were not significantly modified. The lack of a complete association between the concentrations of the two hormones, considering that corticotrophin stimulates the production of cortisol and cortisol inhibits the production of the former, has also been reported in practitioners of transcendental meditation.⁴⁶ The fact that not all corticotrophin pulses are followed by a comparable rise in plasma cortisol⁴⁷ and the possibility that the pituitary and adrenal glands are under different regulatory mechanisms⁴⁸ could explain the apparent “dissociation” between the levels of these hormones in practitioners of meditation. As it is well established that both corticotrophin and cortisol exert an inhibitory effect on monocyte/macrophage functions and differentiation,^49,50 it is plausible to expect that the reduction of blood concentrations of these hormones could be accompanied by activation of phagocytosis and production of hydrogen peroxide by monocytes, as observed in the present study.

Although a stimulatory effect on monocytes/macrophages is attributed to melatonin,^51

–54 the activation of phagocytosis and the increased production of hydrogen peroxide that the present study demonstrated in the higher practitioners were probably not due to the action of this hormone because its levels remained stable even after the period of meditation training.

The mechanisms whereby meditation exerts its beneficial effects are not completely elucidated. Since the majority of modalities of meditation include a stage of mind quieting and relaxation, it is conceivable that at least part of their effects are due to the reduction of sympathetic activation⁵⁵ (and/or to the increase of the parasympathetic tonus⁵⁶), and to a possible reduction in the activation of the hypothalamic–pituitary–adrenal axis.⁵⁷ However, pranic meditation as well as qigong may also act by means of the metenergy captured and distributed through the exercises of pranayama and visualization. Indeed, it has been shown that metenergy is capable of influencing the functions, proliferation, and differentiation of cells,^58
–60 probably by acting on their enzymatic system.^61,62 The possibility that the raised production of hydrogen peroxide by monocytes that the authors found in the group of higher practitioners was due, at least in part, to this mechanism cannot be ruled out.

Some features concerning the experimental design of the present investigation deserve to be commented on. The relatively reduced number of subjects studied (n=29) was an intrinsic limitation of the adopted methodology. To assure the reliability of the functional analyses of phagocytes, the cells have to be processed and analyzed immediately after their collection. Moreover, in order to avoid the variability between observers, all experimental procedures involving the assessment of phagocyte functions were carried out by the same investigator. These facts limit the number of experimental samples capable to be collected and processed at each time point of the experiment (1st, 5th, and 10th weeks) and therefore, the number of subjects of the research.

Some concerns have been raised about the absence of a control group in scientific experiments, as is the case of the present investigation. It is said that this possible limitation would weaken the impact of the conclusions, since it is not possible to rule out a possible placebo effect. Several arguments for not using a control group in the present experiment could be presented: (1) the group under investigation was composed of healthy people from the community, therefore, no “expectation to improve” would be anticipated; even if this was the case, it seems implausible to expect a modification of cell functions or hormone levels; (2) the use of internal controls (the same individual at different time points), rather than external ones, reduces the high interindividual variations frequently found in biologic parameters, and therefore increases the possibility of finding associations that would be ignored otherwise; (3) the pre–post experimental design is frequently adopted in studies on the effects of meditation⁶³ and, due to the peculiarities of this strategy, has been considered as the most suitable way to assess the effects of meditation and allied processes.⁶⁴

Conclusions

The present investigation is the first to show that a short program of pranic meditation was able to upregulate the function and metabolism of phagocytes, in parallel with the reduction of the plasma levels of corticotrophin. This study's results point to a possible causal effect between these events, and indicate that pranic meditation could be useful for upregulating the function and metabolism of monocytes.

Footnotes

Acknowledgments

We are grateful to Drs. Imaculada Junqueira and Selma Kückelhaus for helpful advice, and to Érica Rocha, Nelson Pelet, José Siqueira, Shirley Couto, Marthina Gomes, and Rafael Guimarães for technical help.

Disclosure Statement

No competing financial interests exist.

References

Mishra

. Scientific Basis of Ayurvedic Therapies. CRC Press, 2004.

Pole

. Ayurvedic Medicine. Churchill-Livingstone: Elsevier, 2006.

Hintz

, Yount

, Kadar

et al. Bioenergy definitions and research guidelines. Altern Ther Health Med, 2003; 9:13–30.

Rubik

. The biofield hypothesis: Its biophysical basis and role in medicine. J Altern Complement Med, 2002; 8:703–717.

Rosch

. Bioelectromagnetic and subtle energy medicine: The interface between mind and matter. Ann N Y Acad Sci, 2009; 1172:297–311.

Yan

, Lu

, Jiang

et al. Certain physical manifestation and effects of external qi of Yan Xin Life Science Technology. J Sci Explor, 2002; 16:381–411.

Radin

, Hayssen

, Emoto

, Kizu

. Double-blind test of the effects of distant intention on water crystal formation. Explore, 2006; 2:408–411.

Shao

, Zhang

, Chen

et al. Effects of external qi of qigong with opposing intentions on proliferation of Escherichia coli. J Altern Complement Med, 2009; 15:567–571.

Ohnishi

, Ohnishi

. Philosophy, psychology, physics and practice of Ki. Evid Based Complement Altern Med, 2009; 6:175–183.

10.

Lee

, Rim

, Jeong

D-M

et al.

Nonlinear analysis of heart rate variability during qi therapy (External Qigong)

Am J Chin Med, 2005; 33:579–588.

11.

Oswal

, Nagarathna

, Ebnezar

, Nagendra

. The effect of add-on yogic prana energization technique (YPET) on healing of fresh fractures: A randomized control study. J Altern Complement Med, 2011; 17:253–258.

12.

Lei

, Bi

, Zhang

, Cheng

. The antitumor effects of qigong-emitted external qi and its influence on the immunologic functions of tumor-bearing mice. J Tongji Med Univ, 1991; 11:253–256.

13.

Baldwin

, Wagers

, Schwartz

. Reiki improves heart rate homeostasis in laboratory rats. J Altern Complement Med, 2008; 14:417–422.

14.

Gronowitz

, Jhaveri

, Clarke

et al. Therapeutic touch stimulates the proliferation of human cells in culture. J Altern Complement Med, 2008; 15:567–571.

15.

Rozanova

, Rozanova

. The effect of energy healing on in vitro tumour cells proliferation cell cycle and apoptosis: An experimental study. J Cancer Sci Ther, 2010; 1:11–15.

16.

Rein

. The in vitro effect of bioenergy on conformational state of human DNA in aqueous solution. Acupunct Electrother Res, 1995; 20:173–180.

17.

Jhaveri

, Walsh

, Wang

et al. Therapeutic touch affects DNA synthesis and mineralization of human osteoblasts in culture. J Orthop Res, 2008; 26:1541–1546.

18.

Yan

, Lin

, Li

et al. Structure and property changes in certain materials influenced by the external qi of qigong. Mat Res Innovat, 1999; 2:349–359.

19.

Tiller

. A personal perspective on energies in future energy medicine. J Altern Complement Med, 2004; 10:867–877.

20.

Tiller

. What are subtle energies? J Sci Explor, 1993; 7:293–304.

21.

Geissmann

, Manz

, Jung

et al. Development of monocytes, macrophages and dendritic cells. Science, 2010; 327:656–661.

22.

Iwasaki

, Medzhitov

. Regulation of adaptive immunity by the innate immune system. Science, 2010; 327:291–295.

23.

Glocker

, Grimbacher

. Chronic mucocutaneous candidiasis and congenital susceptibility to Candida. Curr Opin Allergy Clin Immunol, 2010; 10:542–550.

24.

, Aymeric

, Locher

et al. The dendritic cell-tumor cross-talk in cancer. Curr Opin Immunol, 2011; 23:146–152.

25.

Smith

. Neuropeptides as signal molecules in common with leukocytes and the hypothalamic–pituitary–adrenal axis. Brain Behav Immun, 2008; 22:3–14.

26.

Reyes-García

, García-Tamayo

. A neurotransmitter system that regulates macrophage pro-inflammatory functions. J Neuroimmunol, 2009; 216:20–31.

27.

Turnbull

, Rivier

. Regulation of the hypothalamic-pituitary-adrenal axis by cytokines: Actions and mechanisms of action. Physiol Rev, 1999; 79:1–7.

28.

Silverman

, Pearce

, Biron

, Miller

. Immune modulation of the hypothalamic-pituitary-adrenal (HPA) axis during viral infection. Viral Immunol, 2005; 18:41–78.

29.

Berczi

, Quintanar-Stephano

, Kovacs

. Neuroimmune regulation in immunocompetence, acute illness, and healing. Ann N Y Acad Sci, 2009; 1153:220–239.

30.

Rodríguez

, Marchena

, Nogales

et al. Correlation between the circadian rhythm of melatonin, phagocytosis, and superoxide anion levels in ring dove heterophils. J Pineal Res, 1999; 26:35–42.

31.

Morrey

, McLachlan

, Serkin

, Bakouche

. Activation of human monocytes by the pineal hormone melatonin. J Immunol, 1994; 153:2671–2680.

32.

Pick

. Microassays for superoxide and hydrogen peroxide production and nitroblue tetrazolium reduction using an enzyme immunoassay microplate reader. Methods Enzymol, 1986; 132:407–421.

33.

Green

, Wagner

, Gloowski

et al. Analysis of nitrate, nitrite, and [¹⁵N]nitrate in biological fluids. Analyt Bioch, 1982; 126:131–138.

34.

Muniz-Junqueira

, Peçanha

LMF

, Silva-Filho

et al. Novel microtechnique for assessment of postnatal maturation of the phagocytic function of neutrophils and monocytes. Clin Diagn Lab Immunol, 2003; 10:1096–1102.

35.

Serbina

, Jia

, Hohl

et al. Monocyte-mediated defense against microbial pathogens. Ann Rev Immunol, 2008; 26:421–452.

36.

Taylor

, Cullen

, Martin

. Apoptosis: Controlled demolition at the cellular level. Nat Rev Mol Cell Biol, 2008; 9:231–241.

37.

Mantovani

, Sica

. Macrophages, innate immunity, and cancer: Balance, tolerance, and diversity. Curr Opin Immunol, 2010; 22:231–237.

38.

Auffray

, Sieweke

, Geissmann

. Blood monocytes: Development, heterogeneity, and relationship with dendritic cells. Annu Rev Immunol, 2009; 27:669–692.

39.

Di Comite

, Grazia-Sabbadini

, Corti

et al. Conversation galante: How the immune and the neuroendocrine systems talk to each other. Autoimmun Rev, 2007; 7:23–29.

40.

Kemp

. Qigong as a therapeutic intervention with older adults. J Holist Nurs, 2004; 22:351–373.

41.

, Li

, Garcia

et al. Genomic profiling of neutrophil transcripts in Asian qigong practitioners: A pilot study in gene regulation by mind-body interaction. J Altern Complement Med, 2005; 11:29–39.

42.

Lee

, Kim

, Ryu

. Qi-training (qigong) enhanced immune functions: What is the underlying mechanism? Int J Neurosci, 2005; 115:1099–1104.

43.

Orme-Johnson

. Commentary on the AHRQ report on research on meditation practices in health. J Altern Complement Med, 2008; 14:1215–1221.

44.

Vedamurthachar

, Janakiramaiah

, Hegde

et al. Antidepressant efficacy and hormonal effects of Sudarshana Kriya Yoga (SKY) in alcohol dependent individuals. J Affect Disorders, 2006; 96:249–253.

45.

Carlson

, Speca

, Faris

, Patel

. One year pre–post intervention follow-up of psychological, immune, endocrine and blood pressure outcomes of mindfulness-based stress reduction (MBSR) in breast and prostate cancer outpatients. Brain Behav Immun, 2007; 21:1038–1049.

46.

Infante

, Peran

, Martinez

et al. ACTH and beta-endorphin in transcendental meditation. Physiol Behav, 1998; 64:311–315.

47.

Haus

. Chronobiology in the endocrine system. Adv Drug Deliv Rev, 2007; 59:985–1014.

48.

Bornstein

, Engeland

, Ehrhart-Bornstein

et al. Dissociation of ACTH and glucocorticoids. Trends Endocrinol Metab, 2008; 19:175–180.

49.

Baybutt

, Holsboer

. Inhibition of macrophage differentiation and function by cortisol. Endocrinology, 1990; 127:476–480.

50.

Billing

, Fack

, Turner

et al. Cortisol is a potent modulator of lipopolysaccharide-induced interferon signaling in macrophages. Innate Immun, 2011; 17:302–320.

51.

Massion

, Teas

, Hebert

et al. Meditation, melatonin and breast/prostate cancer: Hypothesis and preliminary data. Med Hypotheses, 1995; 44:39–46.

52.

Currier

, Sun

, Miller

. Exogenous melatonin: Quantitative enhancement in vivo of cells mediating non-specific immunity. J Neuroimmunol, 2000; 104:101–108.

53.

Morrey

, McLachlan

, Serkin

et al. Activation of human monocytes by the pineal hormone melatonin. J Immunol, 1994; 153:2671–2680.

54.

Garcia-Maurino

, Gonzalez-Haba

, Calvo

et al. Melatonin enhances IL-2, IL-6, and IFN-gamma production by human circulating CD4+ cells: A possible nuclear receptor-mediated mechanism involving T helper type 1 lymphocytes and monocytes. J Immunol, 1997; 159:574–581.

55.

Curiati

, Bocchi

, Freire

et al. Meditation reduces sympathetic activation and improves the quality of life in elderly patients with optimally treated heart failure: A prospective randomized study. J Altern Complement Med, 2005; 11:465–472.

56.

Solberg

, Ingjer

, Ekberg

et al. Blood pressure and heart rate during meditation. J Psychosom Res, 2000; 48:273–286.

57.

Carlson

, Speca

, Patel

, Goodey

. Mindfulness-based stress reduction in relation to quality of life, mood, symptoms of stress and levels of cortisol, dehydroepiandrosterone sulfate (DHEAS) and melatonin in breast and prostate cancer outpatients. Psychoneuroendocrinology, 2004; 29:448–474.

58.

Fukushima

, Kataoka

, Hamada

et al. Evidence of qi-gong energy and its biological effect on the enhancement of the phagocytic activity of human polymorphonuclear leukocytes. Am J Chin Med, 2001; 29:1–16.

59.

Lee

, Kim

, Ryu

. Qi-training (qigong) enhanced immune functions: What is the underlying mechanism? Int J Neurosci, 2005; 115:1099–1104.

60.

Ohnishi

, Ohnishi

, Nishino

. Ki-energy (life-energy) protects isolated rat liver mitochondria from oxidative injury. Evid Based Complement Altern Med, 2006; 3:475–482.

61.

Yan

, Xia

Z-Q

, Shen

, Traynor-Kaplan

. External qi of Yan Xin Life Science Technology can revive or suppress enzyme activity of phosphatidylinositol 3-kinase. Bull Sci Technol Soc, 2002; 22:403–406.

62.

Yan

, Shen

, Zaharia

et al. Involvement of phosphatidylinositol 3-kinase and insulin-like growth factor-I in YXLST-mediated neuroprotection. Brain Res, 2004; 106:198–206.

63.

Ospina

, Bond

, Karkhaneh

et al. Meditation practices for health: State of the research. Evid Rep Technol Assess, 2007; 155:1–263.

64.

Aickin

. Beyond randomization. J Altern Complement Med, 2002; 8:765–772.