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.


5 responses to “What Happens to Your Body When You Stop Exercising For a Month?”

  1. Avatar Debbie says:

    Oh, boy, is this true! I had foot surgery in August. Not only was I sidelined from exercise, but I was literally flat on my back for two weeks. I wasn’t allowed up except to go to the bathroom. Within a few days, it was visibly noticeable that I had lost muscle tone in my legs. I lost muscle and gained fat almost immediately. The minute I got the stitches removed after three weeks, I hit the gym, while wearing one of those big, black boots. I still had a pin in my toe, plus I wasn’t allowed to put any stress on the foot, so there were some machines I couldn’t do. But I persevered. Swimming wasn’t allowed for 5 weeks.

    My foot is healing just fine, but this enforced inactivity sure messed with my body and my head. In fact, I’m still trying to overcome from the emotional, mental and physical effects of the surgery and other detrimental aspects of this time period.

  2. Avatar Bill W says:

    Avid bicycle rider (60 to 100+ miles per ride) and I had to sit idle with knee problems for a few weeks. Not only has my form/strength suffered but the mental toughness to go long is hard to recover too.

  3. Avatar Jason Langdon says:

    You lose strength but muscle memory will have you regain your strength in a shorter period then it took to lose it. Also, depending on the type of exercise you were doing, a month off will help with recovery.

    Yes, you MIGHT gain weight but there is a difference between gaining weight as seen on a scale an gaining actual fat. You probably will gain something if you don’t adjust your macro/calorie consumption to compensate for your lack of exercise.

  4. Avatar Atto Hamdy says:

    As development process needs to be progressed over time, as well regression will occur over a shorter time frame in relation with development process.

    My athletes start dropping in numbers and levels with in 72 hours as its scientifically proven that the muscular and energy systems in human body start to regress within 72 hours when an individual is not activating it.

    The secret to reach goals, transformations, healthy life style, & peaking in your levels is consestcy and by being competent over a long time frame by putting your systems in constant stress/recover cycles where you will no longer feel that stress anymore. Once that is achieved and implemented in your life you will be hitting your goals and even reach your peak not only to just hit a general healthy life style.

  5. Avatar kc10buckeye says:

    Good article — Is there a similar article outlining the benefits of starting fitness — I like the format of this article, and was looking for one with the effects on Blood Pressure, glucose, sleep, etc. Thanks.

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