Semaglutide saps mice’s motivation to run

CHICAGO — Mice love to run. But now not when they’re taking semaglutide, the diabetes and weight-loss drug sold as Ozempic and Wegovy. While on the drug, mice ran less on a wheel in a cage, a brand new know about shows.

The outcomes, presented October 7 on the annual meeting of the Society for Neuroscience, are preliminary. Still, the unexpected finding raises questions about whether such more and more renowned drugs, which mimic a hormone regularly which is commonly is often called GLP-1, would per chance be tinkering with people’s motivation to exercise (SN: Eight/29/23).

The new results fit with what’s known about these drugs’ abilities to vary brain behavior, says neuroscientist Karolina Skibicka of Penn State University and the University of Gothenburg in Sweden. “I believe it’s in point of fact important,” she says of the new finding on exercise. “I’ve spent most of my career having a look at these drugs. But I still think we don’t know the entirety.”

Mice with unfettered get entry to to a wheel will use it extensively, running a whopping 10 kilometers a day, says Ralph DiLeone, a neuroscientist at Yale University. “You probably have gotten you have got gotten got a look into how lots they’re running, it’s just nuts,” he says.

But mice given semaglutide for seven days ran significantly lower than their usual mileage, DiLeone and colleagues found. These mice — both men and women folk — reduced their average every day distance by about 38 percent. When the mice went off semaglutide, their running distance snapped back to normal.

As expected, the mice on semaglutide lost weight. But mice on restricted diets that lost in regards to the identical amount of weight without the drug didn’t change their running habits, the researchers found. That implies weight-loss isn’t causing the new sedentary behavior.

As a substitute, this reduced running reflected a lack of motivation, in addition experiments suggested. Researchers trained the mice to release their running wheel by poking their noses into a slot, working for their workout, truly. Mice would in most cases be willing to poke multiple times to release their running wheel. But mice on semaglutide poked less, suggesting that they were less desirous to release their wheel.

It’s too soon to say whether the mice’s altered running habits in point of fact relate to the more complicated exercise decisions that people make. If these drugs do make people less motivated to exercise, Skibicka says, doctors would per chance should change how they talk with patients about these drugs, “saying, ‘Hey, it is able to be easy to also feel like you don’t would desire to exercise. Alternatively it’s in point of fact important that you just do.’”

GLP-1 drugs assist people shed extra pounds, but part of that weight is muscle, Skibicka says. “If you happen to add reduced exercise to this, now that’s a difficulty,” she says. “Muscle mass is highly important for health. Being lean without muscle mass is now not a healthy state either.”

Alternatively it truly is miles ready to be that the mice’s running is more like a compulsion. “It truly is much conceivable that the mice are also exercising compulsively,” DiLeone says, and that semaglutide may in the reduction of this urge. That matches with other results that suggest the drug may ease addictions, most likely by affecting the brain’s reward systems (SN: Eight/30/23). Some people taking semaglutide have reported less desire for food, alcohol and nicotine.

It’s tricky to grasp whether these results apply to people, says exercise physiologist Glenn Gaesser of Arizona State University in Phoenix. He's now not aware about any evidence that people exercise less while on these drugs. “That said, fatigue, low energy and nausea are reported unintended effects,” and those symptoms may per chance sap people’s motivation to be active.

“Physical activity and fitness have a greater impact on life span and health span than weight-loss,” Gaesser says. He's concerned that individuals that view exercise best as a weight-loss strategy “would per chance be less inclined to be physically active after taking one of many new GLP-1 drugs by thinking, ‘Why exercise since I may shed extra pounds with a drug?’  That should be a massive mistake.”