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Rehabilitation Practice and Science

Translated Title

高山上短期居留對心跳頻率、動脈血壓及攝氧性運動能力之影響

Abstract

The effects of short-term residence at high altitude on cardiopulmonary functions at rest and during exercise have been reported, but the change of maximal physical performance on return from altitude is not well established yet. In this study the authors tried to make clear the difference of heart rate, arterial pressure, and physical performance between sea-level and at high altitude of over 3,650 m. Besides, there was an attempt to investigate the effects of short-term residence at high altitude on cardio-pulmonary functions and physical performance on return from high altitude.Twenty-five young healthy men aged from 17 to 38 years were studied at sea-level and at high altitude of over 3,650m on the 6th or 11th day of residence. The mean resting heart rate of older group was remarkably increased from 68.7±8.1 beat/ min at sea-level to 95.3±17.0 beat/ min at high altitude, while the mean resting arterial pressure of younger group was significantly increased from 118.2/ 73.8 mmHg to 130.5/ 87.0 mmHg. Every subject successfully performed 5 minutes of step exercise with 40 cm in height and 30 steps per minute at sea-level, but there were 8 subjects (40%) who could not complete the same workload at high altitude of over 3.650m. Besides, the post-exercise mean diastolic pressure was significantly increased from 58.4±13.8 mmHg at sea-level to 80.0±11.9 mmHg at high altitude. Those findings suggested that cardiovascular functions and physical performance were changed at high altitude by hypoxia (barometric pressure = 478 mmHg) and low temperature around 0℃. These changes might also be modified by individual physical fitness and age. Measurement of exercise duration, heart rate, minute ventilation, and oxygen uptake were studied during Bruce treadmill exercise test until these subjects were exhausted. On the third day on return from high altitude, the exercise duration, minute ventilation and oxygen uptake during submaximal and maximal exercise were not significantly different from the values determined before. Only the heart rates at mild exercise and at the end of 1, 2, 3, and 10 minutes after maximal treadmill exercise were significantly lower than before. Although improvement of maximal physical performance could not be confirmed, some residual effect on the cardiac function on return from high altitude was highly suggested by the heart rate response during exercise and recovery period.

Language

Traditional Chinese

First Page

44

Last Page

52

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