New research from the University of Virginia revealed high-intensity exercise may be superior to moderate-intensity exercise for reducing ghrelin levels and modifying hunger responses, with effects varying by sex.
In the randomized, three-arm crossover study published in the Journal of the Endocrine Society, researchers found high-intensity exercise significantly decreased levels of both acylated and deacylated ghrelin compared to moderate-intensity exercise or no exercise. Only female participants showed reduced acylated ghrelin levels during high-intensity exercise.
The trial included 8 male participants and 6 female participants who completed three conditions: no exercise, moderate-intensity exercise at lactate threshold, and high-intensity exercise at 75% of the difference between lactate threshold and peak oxygen consumption.
Female participants demonstrated higher baseline levels of total ghrelin and deacylated ghrelin compared to males. Both sexes exhibited reduced deacylated ghrelin levels during high-intensity exercise, but the response pattern differed between sexes.
The exercise sessions were matched for energy expenditure but varied in duration. Blood samples were collected via indwelling catheter at baseline, every 10 minutes for the first hour, and every 30 minutes for the remaining two hours.
Regarding hunger perception, moderate-intensity exercise resulted in higher hunger scores compared to the control condition. Male participants reported increased hunger during moderate-intensity compared to high-intensity exercise, while females reported higher hunger scores during moderate-intensity compared to control conditions.
Study limitations included a small sample size, particularly in the female group, and the protocol's requirement for overnight fasting. Additionally, the study only included lean subjects, potentially limiting generalizability to individuals with overweight or obesity.
One study author disclosed being an Editor for Journal of the Endocrine Society but played no role in the Journal’s evaluation of the manuscript.