Correct option is C
Detailed Explanation:
Let’s evaluate each of the statements in the context of heat acclimatization:
Statement A: Vasoconstriction starts in skin at a lower body temperature.
- Incorrect. During heat acclimatization, vasodilation occurs to promote heat loss by increasing blood flow to the skin. Vasoconstriction typically occurs when the body is trying to retain heat (e.g., in cold environments), not in a hot environment.
Statement B: Salt concentration in sweat is increased.
- Incorrect. With heat acclimatization, the body typically reduces the salt concentration in sweat, which allows for more efficient water loss and better cooling while conserving sodium. This is a feature of acclimatization that helps reduce dehydration and maintains electrolyte balance.
Statement C: The sweat secretion over the skin is more effectively distributed for optimum use of the effective surface area for evaporative cooling.
- Correct. During heat acclimatization, the body adjusts to release sweat more efficiently across the skin's surface, maximizing the area for evaporative cooling and improving the efficiency of cooling mechanisms.
Statement D: The sweat glands maintain high output for longer periods.
- Correct. As part of heat acclimatization, the body adapts to produce sweat at a higher rate for longer periods of time, increasing the body’s ability to cool itself and reducing the risk of overheating.
Statement E: The threshold for start of sweating is increased.
- Incorrect. The sweating threshold actually decreases during heat acclimatization, meaning the body starts sweating at a lower temperature to promote cooling sooner and more efficiently in hot environments.
