Blood pressure trend of lowlanders during first 6 days of acclimatisation to high altitude

Objectives: The present study was planned to delineate the blood pressure (BP) response of the lowlanders during initial 6 days of acclimatisation to high altitude. Materials and Methods: 398 normotensive sojourners at sea level ascended to HA (3,500 m). Blood pressure response of these subjects were analysed for 6 consecutive days at HA. Based on the BP response of these subjects on the 6th day at HA they were divided into two groups: HBP-high BP group and NBP- normal BP group. Results: It showed that on 6th day at HA, 51 out of 398 subjects presented with BP?140/90 mmHg (HBP) while others remained normotensive (NBP). Comparative systolic BP of HBP and NBP groups during successive days at HA were as follows: HA day 1 (146.8 ± 13.7 mmHg vs 146.3 ± 8.8 mmHg, p>0.05), HA day 4 (144.5 ± 8.7 mmHg vs 135.0 ± 7.0 mmHg, p<0.05) and HA day 6 (148.1 ± 7.9 mmHg vs 131.7 ± 5.3 mmHg, p<0.05). Whereas, diastolic BP of HBP and NBP groups were: HA day 1 (94.0 ± 8.1 mmHg vs 93.2 ± 6.6 mmHg, p>0.05), HA day 4 (88.9 ± 6.0 mmHg vs 85.3 ± 5.1 mmHg, p<0.05) and HA day 6 (93.8 ± 6.3 mmHg vs 83.7 ± 3.8 mmHg, p<0.05). Conclusion: It was found that NBP had initially raised BP which returned to normal levels after acclimatisation period of 6 days, but in HBP, it started rising after 4th day. It can be concluded that those individuals whose BP on 6th day at HA does not return to normal after acclimatisation period needs regular follow up as these individuals can have a delayed acclimatisation normalising BP later on or can become hypertensive subsequently

Sleep architecture at 4300 m altitude in a sample of Indian lowlanders.

The present study aimed to evaluate sleep architecture at 4300m in a sample of 10 healthy Indian lowlanders, mean age 25.7±5.1 yrs. Polysomnography on two consecutive nights each was performed at sea level and 4300 m, the first night for adaptation and the second one for actual recording. Total sleep time reduced from 433.33±8.95 to 412.06±13.13 minutes (P<0.0005), sleep latency increased from 11.56±6.85 to 22.22±7.95 minutes (P<0.0025), deep NREM sleep (S3+S4) reduced from 79.56±28.45 to 45.39±25.32 minutes (P<0.01), light NREM sleep (S1+S2) increased from 272.94±20.63 to 296.72±23.24 minutes (P<0.05), REM decreased from 80.89±7.65 to 69.94±11.30 minutes (P<0.02) and periodic breathing was present in 4 of 10 participants on the second night at 4300 m. Decreased sleep quality (P<0.0005) and increased sleep disturbances (P<0.0005) were reported in subjective ratings at high altitude. Changes in sleep architecture similar to but of a greater magnitude are present on the second night of staged induction to 4300 m, than reported at 3500 m in our earlier study.