A rigorous workout suppresses hunger more than moderate exercise in healthy adults, with females potentially more affected, according to a small study published in the Journal of the Endocrine Society.
The study investigates how exercise intensity affects ghrelin levels and appetite in men and women. Ghrelin, known as the “hunger hormone,” is linked to feelings of hunger.
“We discovered that high-intensity exercise reduces ghrelin levels more effectively than moderate-intensity exercise,” said lead author Kara Anderson, Ph.D., from the University of Virginia and the University of Virginia Health System in Charlottesville, Virginia. “Additionally, we found that individuals felt ‘less hungry’ after high-intensity exercise compared to when they engaged in moderate-intensity exercise.”
Ghrelin circulates in acylated (AG) and deacylated (DAG) forms, which are known to affect appetite. The study noted that data on the impact of exercise intensity on AG and DAG levels and their effects on appetite is sparse and primarily limited to males.
To address this shortfall, the study examined eight males and six females. Participants fasted overnight and then completed exercises of varying intensity levels, determined by blood lactate measurements, followed by self-reported measurements of appetite.
The study noted that females had higher levels of total ghrelin at baseline compared with males. However, only females demonstrated “significantly reduced AG” following the intense exercise.
“We found that moderate intensity either did not change ghrelin levels or led to a net increase,” the study noted. These findings suggest that exercise above the lactate threshold “may be necessary to elicit a suppression in ghrelin.”
Researchers also acknowledged that more work is needed to determine the extent to which exercise’s effects differ by sex.
Ghrelin has been shown to have wide-ranging biological effects in areas including energy balance, appetite, glucose homeostasis, immune function, sleep, and memory.
“Exercise should be thought of as a ‘drug,’ where the ‘dose’ should be customized based on an individual’s personal goals,” Anderson said. “Our research suggests that high-intensity exercise may be important for appetite suppression, which can be particularly useful as part of a weight loss program.”