What is one effect of dehydration on athletic performance?

• A. It impairs thermoregulation, reduces endurance, and can worsen cognitive performance.
• B. It improves endurance.
• C. It has no effect on endurance.
• D. It enhances thermoregulation.

Answer: (A)

Dehydration disrupts the body's ability to cool itself and sustain performance during exercise. When you lose fluids, plasma volume drops, which makes sweating less effective and skin blood flow less optimal. As a result, core temperature rises more quickly during activity, and the heart has to work harder to pump a smaller volume of blood, leading to a higher heart rate and greater perceived effort. This combination reduces endurance because fatigue sets in sooner and performance declines. At the same time, dehydration can impair brain function, affecting attention, decision making, and reaction time—key cognitive skills athletes rely on during sport. Even modest fluid loss can contribute to these problems, so the overall effect is a clear reduction in endurance, poorer thermoregulation, and possible cognitive drawbacks. The other ideas—improving endurance, having no effect, or enhancing thermoregulation—do not align with how fluid loss impairs heat management and performance.