Hunger cues are influenced by more than just an empty stomach, with hormones like ghrelin playing powerful roles as appetite regulators. A recent study found that both exercise intensity and sex significantly influence ghrelin levels, markedly influencing appetite.

Researchers measured lactate threshold and peak oxygen consumption in 14 untrained males and females engaging in three different cycling sessions: a control session with no exercise, a moderate-intensity session at lactate threshold, and a high-intensity session at 75% of the difference between lactate threshold and peak oxygen consumption. Then, they assessed the participants' appetite perception.

They found that females had considerably higher total ghrelin and deacylated ghrelin levels at baseline than males. In both groups, high-intensity exercise promoted lower levels of deacylated ghrelin than moderate-intensity and no-exercise sessions. Notably, only females exhibited reduced acylated ghrelin levels during high-intensity exercise. Additionally, hunger scores were higher during moderate-intensity sessions than they were during no exercise.

Ghrelin, often called the “hunger hormone,” is primarily produced in the stomach and stimulates appetite. Deacetylated ghrelin has different effects on appetite regulation than its acylated counterpart.

These findings suggest that high-intensity exercise is more effective than moderate-intensity exercise in lowering ghrelin levels and suppressing hunger, with noticeable differences between sexes in this response. High-intensity exercise also promotes brain health. Learn more in this clip featuring Dr. Martin Gibala.