Uday Sankar Ray

Improvement of Glutathione and Total Antioxidant Status with Yoga

OBJECTIVE Several studies suggest that yoga can decrease oxidative stress. However reports are scanty regarding whether yoga training can improve the glutathione level of individual. This study is designed to appraise the role of yoga in maintaining glutathione (reduced and oxidized) levels and antioxidant status. STUDY DESIGN This study was conducted on healthy male volunteers from the Indian Navy, who were divided into two groups--a yoga (n = 30) group and a control (n = 21) group. The yoga group was trained in yoga for 6 months. The yoga schedule consisted of prayers, asana, pranayama, and meditation. The control group practiced routine physical training exercise for 6 months. Blood samples were collected when the volunteers were in fasting condition before and after completion of 6-month training period. Reduced and oxidized glutathione, glutathione reductase activity and total antioxidant status (TAS) were estimated. RESULTS Reduced glutathione level increased significantly (p < 0.05) in the yoga group after completion of training. Glutathione reductase activity increased significantly in the control group (p < 0.05). TAS increased significantly (p < 0.001) in the yoga group and decreased significantly (p < 0.001) in the control group. CONCLUSIONS Regular practice of yoga can maintain or improve antioxidant level of the body. The clinical relevance is that yoga practice can be used to maintain the antioxidant defense system under stressful conditions of training as observed in the case of soldiers and athletes.

Sleep Patterns at an Altitude of 3500 Metres

Alterations in sleep pattern during acclimatisation at an altitude of 3500 m were studied on 27 healthy men (20–30 years of age). Of these, 15 were sojourners (SJ), 6 were acclimatised lowlanders (AL) and 6 were high altitude natives (HAN). Baseline sleep profile of SJ was electrophysiologically monitored, initially at Delhi (260 m) and later at 3500 m altitude in Western Himalayas for 2 weeks. At high altitude (HA) the sleep patterns of AL and HAN were also monitored for comparison. There were 4 cases of acute mountain sickness (AMS) among SJ, whose sleep profiles were also recorded. The state of autonomic arousal was assessed by a battery of indices, while the psychological arousal was measured by the anxiety scales. On completion of studies at HA, the SJ were flown back to the plains and re-tested within one week of return. SJ showed curtailment of slow wave sleep (SWS) and frequent short episodes of arousal during sleep at HA. AL and HAN also had lesser amounts of SWS; however, the arousals and awakenings during sleep were less frequent. Subjects who experienced AMS had normal amounts of SWS at HA. There was sympathetic hyperactivity and slight increase in anxiety level in SJ, while HAN and AL had relatively reduced level of sympathetic activity. The curtailment of SWS and frequent arousals observed in SJ during the initial phase of acclimatisation at HA, appear to be adaptive features to prevent the accentuation of arterial hypoxemia due to sleep hypoventilation.

Total antioxidant status at high altitude in lowlanders and native highlanders: role of uric acid.

Hypobaric hypoxia causes oxidative stress and the antioxidant system of the body plays a vital role in controlling it. Urate contributes up to two-thirds of the antioxidant capacity of human blood. The urate production is catalyzed by xanthine oxidase with a concomitant release of free radicals. This study was designed to appraise the role of urate as an antioxidant at high altitude. The study was conducted on 92 male lowlanders and 66 highlanders after ascent to high altitude at 4560 m. Blood was collected at sea level and after 4 weeks of high altitude exposure. In lowlanders, a significant increase in levels of hydroperoxide (551.4 +/- 4.2 micromol/mL vs. 582.0 +/- 3.55, p < 0.001], protein carbonyl (2.4 +/- 0.11 micromol/mL/mg protein vs. 3.03 +/- 0.11, p < 0.001), TAS (1.02 +/- 0.01 mmol/L vs. 1.19 +/- 0.02, p < 0.001), and UA (298.0 +/- 6.68 micromol/L vs. 383.0 +/- 6.55, p < 0.001) was observed at high altitude. These measurements were significantly lower in highlanders than in lowlanders at high altitude. Total antioxidant status (TAS) and uric acid (UA) showed a positive correlation in lowlanders at sea level and in highlanders at high altitude. Hydroperoxide and TAS also showed a positive correlation in both groups at high altitude. This indicates increased oxidative stress at high altitude despite an increase in antioxidant capacity in lowlanders. To conclude, a hypoxia-induced increase in UA contributes an appreciable portion of plasma total antioxidant capacity, but may not be effective in preventing oxidative stress at high altitude.

Physiological responses to cold (10 ~ C) in men after six months' practice of yoga exercises

AbstractA study was conducted on 30 healthy soldiers (age: 40–46 years) to assess the effect of selected yogic exercises (asanas) on some physiological responses to cold exposure. They were randomly divided into two groups of 15 each. One group performed regular physical exercises of physical training (PT), while the other group practised yogic exercises. At the end of 6 months of training, both the groups were exposed together to cold stress at 10°C for 2 h, and the following parameters were periodically monitored during cold exposure: heart rate (fH), blood pressure (BP), cardiac output

Different adaptation patterns of antioxidant system in natives and sojourners at high altitude

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Impact of prolonged high altitude exposure on plasma prolactin in men: effect of age and ethnicity.

, oral temperature (Tor), skin temperature (Tsk), respiratory rate (fR), minute ventilation

Auditory evoked responses in tropical men during sojourn over the arctic region

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