How does physical activity influence energy expenditure?

Physical activity plays a crucial role in influencing energy expenditure by significantly increasing the number of calories burned by the body. When engaging in physical activity, whether it be aerobic exercises like running or anaerobic activities like weightlifting, the body requires additional energy to fuel these movements.

The energy expenditure from physical activity can vary greatly depending on factors such as the intensity, duration, and type of exercise performed. During physical activity, the body relies on different energy sources, including carbohydrates and fats, and this not only contributes to immediate calorie burning but can also elevate metabolism in the hours following exercise, known as the afterburn effect or excess post-exercise oxygen consumption (EPOC).

In contrast to the other choices, claiming that physical activity does not significantly affect energy expenditure, reduces overall energy needs, or only affects energy expenditure during workouts overlooks the comprehensive impact physical activity has on overall metabolism and daily calorie needs. Physical activity is a vital component of energy balance and weight management, as it increases total daily energy expenditure and can aid in achieving a calorie deficit for weight loss or a calorie surplus for muscle gain.