A recent study published in the Journal of the Endocrine Society suggests that intense exercise may be more effective at reducing hunger than moderate exercise, with this appetite-suppressing effect being especially noticeable in women.
Researchers investigated how different exercise intensities impact levels of ghrelin—a hormone linked to hunger—and appetite. Ghrelin, commonly known as the “hunger hormone,” is produced in the stomach and plays a key role in regulating appetite, energy, and metabolism.
How Does Ghrelin Impact Hunger?
Ghrelin exists in two forms, deacylated (DAG) and acylated (AG). DAG, the more abundant form, either suppresses or has no effect on appetite, while AG actively binds to receptors, increasing hunger. Although exercise is known to temporarily reduce hunger, particularly by affecting AG levels, limited research has explored how different intensities of exercise influence these responses, particularly in women, whose hormone levels are affected by estrogen.
Study Design
The study included participants aged 18-55 with body mass indices (BMIs) within a healthy range and no recent weight changes or medical conditions that might impact hormone levels or exercise tolerance. After fasting and avoiding caffeine, alcohol, and exercise, participants took part in three sessions:
1. Control Session: No exercise.
2. Moderate Exercise: Exercise performed at their lactate threshold (a moderate level of effort).
3. High-Intensity Exercise: Exercise at 75% of the level between their lactate threshold and peak oxygen consumption.
During each session, blood samples were collected to measure levels of ghrelin and lactate, a byproduct of high-intensity exercise that may play a role in appetite suppression.
Key Findings
The results show that high-intensity exercise significantly reduced total ghrelin levels, especially in women. Total ghrelin levels were lowest following intense exercise, particularly between 40 and 180 minutes post-exercise. Acylated ghrelin levels (the form linked to hunger) also decreased most in high-intensity sessions, with a more substantial reduction in women than in men.
- Hunger Reduction: Intense exercise was associated with the lowest hunger levels, with women experiencing a greater decrease in AG.
- Lactate and Appetite: Elevated lactate levels during high-intensity exercise correlated with reduced appetite, reinforcing the impact of high-intensity activities on hunger regulation.
- Gender Differences: Women’s AG and total ghrelin responses were more sensitive to high-intensity exercise than men’s, suggesting that women may benefit more from intense exercise for appetite control.
Why This Matters
The findings reveal notable differences in how men and women respond to exercise regarding hunger and appetite regulation. This study suggests high-intensity exercise could be a valuable tool for women seeking to manage hunger and support weight goals.
Further studies could help refine these findings by exploring the effects of chronic high-intensity exercise and considering factors such as obesity. These insights could lead to more tailored exercise guidelines that align with individual health and appetite management goals.
Reference: Anderson, K.C., et al. (2024). "The Impact of Exercise Intensity and Sex on Endogenous Ghrelin Levels and Appetite in Healthy Humans." Journal of the Endocrine Society.
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