Which hormone is primarily responsible for increasing the rate of lipolysis during exercise?

Adrenaline, also known as epinephrine, plays a crucial role in increasing the rate of lipolysis during exercise. When physical activity begins, the sympathetic nervous system is activated, leading to the release of adrenaline from the adrenal glands. This hormone stimulates lipolysis, the process through which triglycerides stored in adipose tissue are broken down into free fatty acids and glycerol. The increased availability of free fatty acids provides a vital source of energy for working muscles during exercise, particularly in endurance activities or when the energy demand exceeds the immediate reserves of glycogen.

Adrenaline acts on specific receptors in adipocytes (fat cells) that facilitate the breakdown of fat stores, thus enhancing the mobilization of fatty acids into the bloodstream. This mechanism is especially important during times of physical stress or increased energy requirements, such as during intense or prolonged exercise, where relying solely on carbohydrate stores may not suffice.

In contrast, hormones like insulin generally work to promote fat storage and decrease lipolysis, while glucagon primarily acts to mobilize glucose from stored glycogen rather than focusing on fat breakdown. Cortisol can have an effect on lipolysis as well, but its main role relates more to glucose metabolism and stress response rather than being the primary driver