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Physical performance and heat tolerance after chronic water loading and heat acclimation
E Kristal-Boneh1, J G Glusman, R Shitrit
1Cardiovascular Epidemiology Unit, Occupational Health and Rehabilitation Institute, Raanana, Israel.
Aviation, Space, and Environmental Medicine
|August 1, 1995
Summary
Heat acclimation (HA) and forced water intake (FWI) both enhance endurance in hot conditions. Combining HA and FWI further improves work duration and tolerance time, with maximal oxygen uptake unchanged but achieved at lower heart rates.
Area of Science:
- Environmental Physiology
- Human Performance
- Exercise Science
Background:
- Heat acclimation (HA) and forced water intake (FWI) are known to improve endurance in hot environments.
- The interaction and combined effects of HA and FWI on human performance in heat were not fully understood.
Purpose of the Study:
- To investigate the combined effects of heat acclimation and forced water intake on endurance and physiological responses in hot environments.
- To compare the efficacy of sequential versus concurrent application of HA and FWI.
Main Methods:
- Nine subjects underwent heat tolerance (HT) tests.
- Two groups received different protocols: one with HA followed by FWI, the other with FWI before and during HA.
- Work duration, work tolerance time, maximal oxygen uptake, and heart rate were measured.
Main Results:
- Both HA and FWI individually increased work duration significantly.
- The combination of HA and FWI further enhanced work tolerance time.
- Maximal oxygen uptake remained unchanged, but maximal heart rate was lower after interventions.
- FWI alone reduced 15 km cycling time by 10%.
Conclusions:
- Both heat acclimation and forced water intake are effective in improving endurance in hot conditions.
- Combining HA and FWI offers additional benefits for work tolerance.
- These interventions lead to more efficient cardiovascular responses during exercise in heat.
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