As a result, over time, pushing yourself a little harder during exercise may help you eat less and gain better weight control.
How Exercise Changes Hunger Hormones
Consider what happened when Tom Hazel, associate professor of kinesiology at Wilfrid Laurier University in Waterloo, Canada, invited nine healthy middle-aged men and women to an exercise lab. let’s During their visit, he assigned them various workouts on different days. include:
- 30 minutes of light running.
- 1 minute of fast, vigorous treadmill running followed by 1 minute of rest, repeated 10 times.
- Do eight 15-second all-out cycling intervals with 2-minute rests in between.
- sitting quietly
This experiment was published in April. Journal of Applied Physiologyemerged from early research over a decade ago. In that study, Hazel and his colleagues found that short sessions of interval training helped many volunteers lose body fat.
The results came as a surprise because these workouts, often called high-intensity interval training or HIIT, seemed too short to burn many calories. What effect does HIIT have on people’s body composition?
The researchers took several blood samples before and after each session to determine how hungry participants felt, and asked them to keep detailed food diaries the day before and the day of training.
Hazel and his colleagues then tested the volunteers’ blood for a variety of substances, including hormones known to suppress or suppress appetite in geese.
The most shocking finding was that lactate levels in people’s bloodstreams spiked after interval sessions compared to levels after moderate running or quiet sitting.
Lactic acid was once thought to be an unwanted waste product produced by muscles during exercise. Most of us believed that lactic acid hurt the body.
but scientists now know Lactic acid is more desirable than harmful. It is a key signaling molecule that activates many of the processes that result in beneficial effects from exercise. It turns out that expelling lactic acid during exercise is mostly a good thing.
And the bloodstreams of middle-aged volunteers in Hazel’s lab flooded with lactic acid after short, strenuous exercise sessions.
More importantly, the higher the lactate level, the lower the amount of acylated ghrelin in the blood. Acylated ghrelin is one of the major appetite-increasing hormones.
In fact, short bouts of intense exercise increased lactate and lowered ghrelin in the process.
Hazel’s lab graduate student Seth McCarthy, who led the new study, said that lactate likely partially blocked the release of acylated ghrelin from the stomach, the usual source, but it’s a possibility. Said I need to check.
More intense, smaller meals
According to the food diary, those who subsequently exercised burned an average of 129 calories on days with 1-minute intervals and 201 calories after repeated 15-second intervals compared to days without exercise. It has been reduced. Moderate running had no measurable effect on diet.
These differences are obviously small. Scientists say these were not statistically significant and could only be caused by people inaccurately recording what they ate at the time. It also suggests that changes to ghrelin are not the only factor at work, as effects vary from person to person.
“Multiple biological signals are thought to be involved in appetite, but there are others,” says David Stensel, a professor of exercise metabolism and exercise and diet at Loughborough University in the UK. “There are many psychological, environmental and personal factors.” . He is a co-author of a scientific review in Appetite, but was not involved in the lactate study.
Still, if repeated over time, even a difference of a few hundred calories per day may help prevent weight gain. Other research is shown.
The bottom line is that if you want to curb your post-exercise appetite, you should increase your pace. Instead of walking on flat ground, challenge yourself to climb long hills by brisk walking or running while waving your arms out of breath. Or pedal the stationary bike at full speed and do a few 15-second sprints.
You don’t need a heart rate monitor or scientific accuracy (but if you enjoy them, aim for a heart rate above about 80% of maximum (roughly speaking, 220 minus your age) ).
Also, expect a reasonable range of effects on your appetite. They’re probably short-lived, and “you need to do exercise every day, or at least a few times a week,” Stensel said.
Additional research is needed for other possible explanations for how exercise affects appetite. in 2017 study In Stensel’s lab, an hour of brisk walking on a treadmill also increased other hormones besides lactate, including GLP-1, which is famously involved in the effects of drugs like Ozempic. However, the increase was orders of magnitude smaller than that seen with this drug.
Overall, most researchers agree that sweat-producing exercise is primarily useful for weight management, or weight gain, rather than weight loss.
But a stable weight is important, and exercise has its own irreplaceable benefits. “The most important role of exercise is to keep people healthy and active enough to stay connected with family, friends and society and to live an interesting and fulfilling life,” said Stensel. Stated.
Have a fitness question? Email YourMove@washpost.com I may answer your question in a future column.
