Scientists Studied the Thermoregulatory and Osmoregulatory Responses in Exercising Human

question 49

Multiple Choice

Scientists studied the thermoregulatory and osmoregulatory responses in exercising human subjects who were experiencing different levels of dehydration (0%, 3%, 5%, and 7% based on body weight) . After exercise, the subjects' body temperatures, sweating rates, and blood solute concentrations were measured. Their results are shown in these three graphs. Note that only sweating rate was measured after each bout of exercise. Body temperature was measured after the first two bouts of exercise, and blood solutes after only the first bout of exercise.
Source: Adapted from Sawka, M. N., Young, A. J., Francesconi, R. P., Muza, S. R., & Pandolf, K. B. (1985) . Thermoregulatory and blood responses during exercise at graded hypohydration levels. J Appl Physiol, 59, 1394-1402.
-Examine the body temperature and sweating rate graphs. Normal body temperatures range from 36.5C to 37.5C. Which of the following best describes how the relationship between osmoregulation and thermoregulation is altered after the first bout of exercise?

• A) The rate of sweating is not high enough to cool body temperatures when dehydration is experienced.
• B) Higher body temperatures increase sweating rates, which in turn create higher dehydration percentages.
• C) Sweating rate is sufficient to maintain normal body temperatures when there is no dehydration.
• D) Greater dehydration increases sweating rates, which in turn increase body temperatures.