Cardiac drift is best described as what phenomenon?

Cardiac drift is best described as what phenomenon?

• A. when heart rate rises due to dehydration
• B. when heart rate rises due to heart attack
• C. when heart rate falls during dehydration
• D. when heart rate remains constant during exercise

Answer: (A)

Cardiac drift describes the gradual rise in heart rate during prolonged, steady exercise even when the workload stays the same. As you exercise longer, body temperature climbs and you lose fluids through sweat. This reduces plasma volume and lowers venous return, which tends to decrease stroke volume. To keep cardiac output up, the heart compensates by increasing heart rate. Dehydration makes this drift more pronounced because the drop in plasma volume and the need to support heat dissipation push the heart to beat faster. This phenomenon isn’t about a heart attack, isn’t a drop in heart rate with dehydration, and isn’t a constant heart rate during exercise. So the best description is heart rate rising due to dehydration.

Cardiac drift describes the gradual rise in heart rate during prolonged, steady exercise even when the workload stays the same. As you exercise longer, body temperature climbs and you lose fluids through sweat. This reduces plasma volume and lowers venous return, which tends to decrease stroke volume. To keep cardiac output up, the heart compensates by increasing heart rate. Dehydration makes this drift more pronounced because the drop in plasma volume and the need to support heat dissipation push the heart to beat faster. This phenomenon isn’t about a heart attack, isn’t a drop in heart rate with dehydration, and isn’t a constant heart rate during exercise. So the best description is heart rate rising due to dehydration.