HIGH-INTENSITY TRAINING OVER 10 DAYS IS NOT EXCESSIVELY STRESSFUL
Ormsbee, M. J., Kinsey, A. W., Chong, M., Friedman, H. S., Dodgez, T., & Fehling, P. C. (2011). Short-term high-intensity interval training and the physiological stress response. Medicine and Science in Sports and Exercise, 43(5). Supplement abstract 3138.
"High-intensity interval training (HIT) has been reported to induce physiological adaptations normally associated with endurance training and reduce stress." This study investigated the effect of 10 days of high-intensity training on the physiological stress response, mood state, and body composition in college-aged individuals. Ss were divided into a high-intensity training group (N = 10) or a no exercise control group (N = 10). Exercise training consisted of two five-day phases on a cycle ergometer. Phase I was 30-minutes with 30-second high-intensity intervals (>90% HRmax) interspersed throughout. Phase II was 20 minutes and consisted of eight, 30-second high-intensity intervals separated by two minutes of active rest (50-60% HRmax). The control group completed filler tasks to match laboratory time invested by the high-intensity training group. The response to stress (the Trier Social Stress Test) was evaluated through measurement of heart-rate variability (HRV), salivary cortisol, and mood state pre- and post-intervention.
Pre- and post-intervention heart-rate variability measures were not significantly different between groups. Pre-intervention heart rates were not different between groups but post-intervention heart rates were significantly lower in the high-intensity training group. Percent changes for salivary cortisol did not change pre- to post-intervention in either group. Mood state and body composition did not change as a result of high-intensity training.
Implication. Ten days of short-term high-intensity training does not elicit physiological changes in autonomic function, hypothalamic-pituitary-adrenal axis reactivity, mood state, or body composition.
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