NCSF Sport Nutrition Specialist Certification (SNS) Practice Test 2025 – The All-in-One Resource to Master Your Certification!

Dehydration has a significant negative impact on the cardiovascular system, primarily manifested through an increase in heart rate. When an individual becomes dehydrated, the volume of blood circulating throughout the body decreases due to a reduction in plasma volume. This drop in blood volume requires the heart to pump more frequently to maintain adequate blood pressure and ensure that oxygen and nutrients are delivered effectively to the muscles and organs. Consequently, the heart rate increases as a compensatory mechanism to maintain cardiovascular function under the stress of dehydration.

In contrast, other options like an increase in stroke volume or a reduction in heart rate would not typically occur with dehydration. Stroke volume, which is the amount of blood pumped by the heart with each beat, may actually decrease as the heart works harder under reduced blood volume conditions. Elevated oxygen uptake is also not directly caused by dehydration; instead, efficient oxygen transport relies heavily on adequate hydration levels for optimal blood viscosity and circulation. Thus, the correct understanding of dehydration's effects properly aligns with the increase in heart rate as the body attempts to counteract the challenges posed by inadequate fluid levels.