During exercise, a biological signal that normally slows fat breakdown has less effect in people who are endurance-trained compared to those who are not, suggesting that training changes how fat tissue responds to this signal.

In men who are endurance-trained, blocking a specific receptor (α2-adrenergic) does not increase fat breakdown during exercise in abdominal fat, but it does increase fat breakdown in men who are not trained, suggesting that endurance training reduces the effect of this receptor in limiting fat breakdown.

In fasted individuals exercising, fat breakdown is more strongly suppressed in obese men than in lean men due to the activity of alpha-2-adrenergic receptors.

Eating a very high-fat meal before exercising reduces the normal biological brake on fat breakdown in fat tissue under the skin, leading to more fatty acids being released into the bloodstream during physical activity.

Men who regularly train for endurance sports show greater fat breakdown in abdominal fat tissue during moderate cycling than untrained men, measured by higher glycerol levels, even when hormone levels like adrenaline and insulin are similar.

People who regularly do endurance exercise, like running or cycling, show increased fat breakdown in abdominal fat tissue during exercise, even when levels of key hormones in the blood do not change. This suggests the fat tissue itself adapts to exercise rather than relying on hormonal signals.