How does physical activity affect heart rate?

Physical activity significantly increases heart rate as the body's demand for oxygen rises, particularly in the muscles that are working. During exercise, the heart pumps faster to supply more oxygen-rich blood to the muscles, supporting their activity and endurance. This adjustment is part of the cardiovascular system's response to the increased metabolic needs that occur during physical exertion.

When you engage in any form of physical activity, your muscles require more energy, which is produced through aerobic metabolism that requires oxygen. Therefore, the heart rate increases to meet this heightened demand, ensuring that sufficient oxygen and nutrients are delivered while also removing carbon dioxide and other metabolic wastes being produced by the active tissues.

In contrast, other options fail to accurately represent the physiological response to exercise. Some suggest that physical activity decreases heart rate or has no effect at all, which contradicts established knowledge of how the heart reacts during activity. Additionally, stating that heart rate is only affected during intense workouts oversimplifies the body's response to exercise; even moderate activities elevate heart rate above resting levels.