How Hard Exercise Quiets the Hunger Hormone
A new study reveals that vigorous exercise lowers levels of the hunger hormone ghrelin, helping explain why hard workouts pause our appetite.
Have you ever run around playing tag or football in the hot sun and realised you did not feel hungry at all right after? On 24 October 2024, scientists in Charlottesville, Virginia, in the United States, shared exciting news about why this happens. They discovered that vigorous, high-intensity workouts quiet down a chemical messenger known as the hunger hormone ghrelin much better than gentle exercise.
The study was led by Dr. Kara Anderson and a team of researchers from the University of Virginia and the UVA Health System. Their work, published in the Journal of the Endocrine Society, reveals how our bodies manage feelings of appetite when we push ourselves during physical activities.
What happened?
To understand appetite during workouts, the scientists invited fourteen healthy adult volunteers, including eight men and six women, to take part in special laboratory tests. All the volunteers fasted overnight before completing exercise routines of varying intensities. The team measured blood lactate levels during each workout session to track how hard each person was working.
The researchers kept a close eye on ghrelin, a special hormone that travels directly to the hypothalamus in the brain to signal when it is time to eat. They tracked two distinct forms of this messenger: acylated ghrelin, which actively stimulates your appetite, and deacylated ghrelin, which makes up roughly 80% of all the ghrelin circulating in the body.
The results showed a clear difference between easy and hard workouts. When participants exercised vigorously above their lactate threshold, laboratory blood tests showed that their overall ghrelin levels dropped. On the other hand, moderate exercise caused no change at all or even led to a slight increase in the hormone. The volunteers also reported feeling significantly less hungry after high-intensity exercise compared to moderate exercise.
Interestingly, the female participants started with higher baseline levels of ghrelin before exercising. When they completed intense workouts, they experienced a particularly notable drop in acylated ghrelin, the specific form that triggers appetite.
This detailed scientific investigation received helpful support from the National Institute of Diabetes and Digestive and Kidney Diseases as well as the University of Virginia’s School of Education and Human Development.
Why does it matter to you?
Whether you are sprinting across the school playground in Delhi, practicing badminton, or playing a fast-paced game of kabaddi, your body is using lots of energy. You might expect your tummy to growl loudly straight after running so hard, but this study explains why you often feel the exact opposite.
Understanding how hormones like ghrelin work helps you listen to your body and understand how it communicates feelings of hunger and fullness. Running fast or playing hard sports can temporarily take away your appetite until your body cools down and rests. Once you rest and recover, your normal hunger signals will return so you can refuel with a healthy meal.
Words to know
- Ghrelin: A chemical hormone made in the body that signals the brain when it is time to eat.
- Hypothalamus: A vital control centre in the brain that receives hunger messages and helps regulate appetite.
- Lactate threshold: A point during tough exercise when a substance called lactate builds up in the blood as muscles work harder.
- Acylated ghrelin: The specific active form of the ghrelin hormone that works directly to stimulate appetite.
Did you know?
Roughly 80% of the ghrelin circulating in your body is deacylated ghrelin, while the remaining acylated ghrelin is the active type that actually makes you feel hungry!
Think about it
How do you usually feel right after running very fast compared to going for a slow walk with your family? Next time you play an energetic sport, pay attention to how long it takes for your appetite to return after you rest.
Quick quiz
Which form of ghrelin actively stimulates appetite according to the study?
- Acylated ghrelin (AG)
- Deacylated ghrelin (DAG)
- Lactate hormone
See the answer
Acylated ghrelin (AG)
Sources
- sciencedaily.com
- medicalnewstoday.com
- endocrine.org
- phillyvoice.com
- sciencealert.com
- sciencefeatured.com
This story was prepared by the Kids Gazette news desk with the help of AI research and writing tools, using the sources listed above.
