The Effect of Energy Deficit on Physical Performance at Sea Level and 4,300 M Altitude
Abstract
We investigated the effect on physical performance of 3 weeks of severe deficit energy intake at sea level (SL) and high altitude (HA, 4300 m). Twenty-six young healthy men (range: 18 to 34 yrs) were assigned for 3 weeks to one of 3 dietary and environmental groups. One group consumed adequate kcal/day to maintain body weight while living at HA (ADQ, n = 7) and two groups consumed 1500 kcal/day less than needed to maintain body weight while living at SL (HYPO, n = 9) or HA (DEF, n = 10). For all groups, physical performance was assessed at SL prior to dietary phase assignment (i.e., baseline), and on days 2, 10 and 20 of the dietary phases. The physical performance tasks were: (1) maximal oxygen uptake (VO2(max)), (2) time to complete 50 lift and carry cycles, (3) number of one-arm elbow flexions (10% body weight at 22 flexions/min), and (4) adductor pollicis muscle exercise (repeated 5 sec static contractions at 50% of maximal force / 5 sec rest). After 3 weeks, relative to the baseline phase, the HYPO and DEF groups lost nearly 5% and 8% body weight, respectively; and 3% and 6% lean body mass, respectively. The body weight and lean body mass losses of the HYPO and DEF groups were significantly greater than those of the ADQ group (P < 0.01), who lost neither body weight nor lean body mass (P > 0.05). VO2(max) was not impaired during body weight loss for the HYPO group (P > 0.05) whereas VO2(max) declined by 30% on day 2 of HA exposure compared to the SL baseline phase for the ADQ and DEF groups. However, VO2(max) for either the ADQ or DEF group did not change with continued HA exposure (P > 0.05). Time to complete the lift and carry task was impaired for the ADQ and DEF groups on day 2 of HA exposure (P < 0.05) but subsequently improved (P < 0.05) for both groups similarly with continued HA exposure. One-a elbow flexion and adductor pollicis muscle performance tasks did not differ among groups either before or during the dietary phases (P > 0.05).
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2001
- Accession Number
- ADA390592
Entities
People
- Anne Friedlander
- Charles S. Fulco
- Paul B. Rock
- Scott Robinson
- Stephen R. Muza
Organizations
- United States Army Research Institute of Environmental Medicine