What Happens to Your Body When You Stop Exercising For a Month?

Jodi Helmer
by Jodi Helmer
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What Happens to Your Body When You Stop Exercising For a Month?

Whether you were sidelined by an injury, let your schedule hinder your workouts or you simply lost the motivation to step on the stairclimber, a longer-than-expected break from your fitness routine can lead to surprising physical, mental and emotional changes.

“Our bodies are designed to be physically active,” says Dr. Kerry Kuehl, director of the Human Performance Lab at Oregon Health and Science University. “If you stop exercising, you’ll lose all of your fitness gains within a few weeks.”


Skipping workouts doesn’t just take its toll on the usual suspects: weight, strength and endurance. Research published in Frontiers in Aging Neuroscience found it triggers changes in the brain, too. After a 10-day period of no exercise, participants in the 2016 study experienced significant decreases in blood flow to multiple regions in their brains, including the hippocampus, the region responsible for memory and learning.

After running the 2016 Boston Marathon, 21 runners agreed to exercise no more than two hours per week (after running almost 32 miles per week during training). The study showed that after four weeks, the athletes experienced significant decreases in the amount of blood pumping to their hearts, making their runs feel harder.

The abundance of mitochondria, the parts of the muscle cell that make energy during exercise, decrease when you abandon your workouts, causing your endurance to plummet, too, according to Jeffrey Horowitz, PhD, a professor of exercise physiology at the University of Michigan. He points to an older study that showed declines in aerobic capacity after just 12 days of training.

Thinking of taking a break from the weight room during an extended vacation or a super busy holiday period? Research published in the Journal of Exercise Rehabilitation found that one month of detraining reversed the beneficial effects of strength training on physical mobility.

Kuehl notes that after two months of logging 30 minutes of moderate-intensity exercise at least three times per week, you increase strength and endurance between 10–15%. Stop exercising and those gains disappear in as few as two weeks.

“It takes a lot longer to get in shape than to fall out of shape,” he says.

Avoiding the gym could increase your percentage of body fat. Research published in the Journal of Strength and Conditioning Research found competitive swimmers who took a five-week break from training experienced weight gain, increases in waist circumference and a 12% increase in body fat.


In general, the stimulus from each session of exercise helps increase — or at least maintain — many of the important aspects of our bodies that keep us fit,” Horowitz explains. “So remove that stimulus and things start decreasing.”

If illness or injuries prevent you from engaging in your regular fitness routine, Kuehl offers this advice: “Never completely rest. Maintain mild-to-moderate physical activity in areas that aren’t affected.”

Cross-training can help prevent significant physiological changes. Instead of running on the pavement, hit the pool; switch from hitting tennis balls to running; trade a high-intensity physical activity for yoga — but don’t push yourself too hard.

“As you return from injury or illness, think about the long-term goals and not trying to get back too quickly to the same level you were right before the injury,” Horowitz says.

About the Author

Jodi Helmer
Jodi Helmer

Jodi Helmer writes about health and wellness for publications like WebMD, AARP, Shape, Woman’s Day, Arthritis Today and Costco Connection among others. She often comes up with the best story ideas while hiking with her rescue dogs. You can read Jodi’s work or follow her on Twitter @helmerjodi.


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