During exercise, how does the body primarily regulate its temperature?

The body primarily regulates its temperature during exercise through sweating and increased blood flow. As physical activity intensifies, the muscles generate heat, increasing the body's core temperature. To maintain a stable internal temperature, the body activates sweat glands, producing sweat that evaporates from the skin's surface, cooling the body down. Additionally, blood flow increases to the skin, facilitating the transfer of heat from the interior of the body to the surface, where it can dissipate into the environment. This dual mechanism of sweating and enhanced circulation is crucial for preventing overheating and ensuring optimal performance during physical activity.

The other choices represent different physiological processes that do not directly contribute to temperature regulation. For example, increasing muscle mass does not actively cool the body, and decreasing hydration can impair performance and temperature control rather than assist it. Resting periodically can help manage fatigue rather than regulating body temperature actively during continuous exercise.