What Happens to Your Brain When You Stop Exercising

by Ellie Kincaid

When you fall off exercise, you may feel like your fitness levels tank, and fast. Turns out, that’s not just a feeling. For endurance junkies, your ability to take in oxygen for cardio decreases seven percent with just three weeks of rest, and exercise newbies are back to square one after four weeks off. In the long term, your body fat percentage, endurance levels, and insulin sensitivity all suffer if your break from exercise goes on and on.
But what’s possibly most disturbing is what happens to your brain. You miss out on the boost of blood flow to the brain exercise gives you according to a study published in August in the journal Frontiers in Aging Neuroscience.
Researchers from the University of Maryland made a hard ask of their study participants — for endurance athletes, who ran an average of 35 miles per week and had been training for about 30 years, to take ten whole days off. Not just take it easy, but completely stop exercising or doing other vigorous physical activity. The researchers even called the athletes to check in and remind them not to sneak in a run. Then they used MRI scans to measure changes in blood flow to the athlete’s brains before and after the break.
After taking all that time off their normal exercise routines, the study participants showed less blood flow to regions of the brain including the hippocampus, which is involved in memory. But even with the reduced blood flow, the athletes didn’t lose ground on the cognitive tests the researchers gave them.
The study results aren’t a reason to worry if you go on vacation and don’t get to work out for a week, J. Carson Smith, associate professor of kinesiology at UMD who led the study, told the New York Times