Effects of Intermittent Altitude Exposures on Acclimatization of 4,300 M
Abstract
This study examined the effects of 3 wk of intermittent exposures (4 h/d, 5 d/wk) to 4,300 m altitude-equivalent, in combination with either passive sitting or exercise training, on the process of altitude acclimatization. Physiological, hematological, physical work performance, and acute mountain sickness (AMS) responses elicited by intermittent exposures to altitude were compared to previously published data from chronic altitude residence. Six adult lowlanders (30 +/- 2 yrs; 70 +/- 3 kg) were acutely exposed (i.e., 30 h) to 4,300 m altitude-equivalent once before (PreAc) and once after (PostAc) a 3-wk period of intermittent altitude exposures. Exercise training during intermittent exposures to altitude did not enhance the magnitude of altitude acclimatization. Thus, data from both groups were combined. Three weeks of intermittent altitude exposures resulted in an 11% increase in resting ventilation, 18% increase in maximal oxygen uptake (VO2(sub max)), 21% improvement in whole-body submaximal endurance performance, 26% increase in small-muscle endurance performance, and elimination of AMS symptoms from PreAc to PostAc. Intermittent altitude exposures accomplished 50%-100% of the expected adaptation to altitude, based on improvements in submaximal endurance performance and absence of altitude illness, when compared to previous chronic altitude residence studies. These large improvements in physical work performance and AMS symptomatology appear to be related to the large degree of ventilatory acclimatization achieved after 3 wk of intermittent altitude exposures. Our findings suggest that 3 wk of intermittent altitude exposures is a useful tool for enhancing physical work performance and eliminating symptoms of AMS in less total exposure hours than chronic altitude residence.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 2001
- Accession Number
- ADA398658
Entities
People
- Allen Cymerman
- Beth A. Beidleman
- Charles S. Fulco
- Daniel T. Ditzler
- Stephen R. Muza
Organizations
- United States Army Research Institute of Environmental Medicine