EXERCISE OUTPUT NOT AFFECTED BY BODY MASS CHANGES DUE TO HYDRATION

McDonough, P., Biggerstaff, K. D., Bearden, S. E., Bergen, J., Cheuvront, S B., & Haymes, E. B. (1998). Maximal cycle ergometry: The effect of changes in hydration status and body mass. Medicine and Science in Sports and Exercise, 30(5), Supplement abstract 1623.

The effects of hydration induced changes in body mass upon repeated bouts of maximal cycle ergometry were evaluated. Males (N = 12) performed four 15-sec bouts of maximal ergometry, each trial being separated by one minute of passive rest. Four conditions were experienced on separate occasions: control, hyperhydration with glycerol, carbohydrate load, and dehydration by passive sweating (-2% BW).

Body mass was significantly different between conditions. Urine osmality was significantly lower in the carbohydrate condition than the other three conditions. Dehydration produced significantly higher heart rates. Absolute or body-weight related total work, peak power output, mean power output, and work output decline did not differ between conditions.

Implication. Body mass changes induced by alterations in hydration status do not affect work performance provided adjustments are made for the change in body mass.

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