"A person who has put on a significant amount of muscle mass can go anywhere from four to 10 weeks and still might look good, and come back and perform reasonably well." So while there's a decline, it's less substantial than it is with your cardiovascular fitness.
They will become smaller and weaker. If you've been doing high intensity exercise or weight training, you'll find a reduction in your muscular endurance. A detraining period of 12 weeks results in decreased muscle mass and muscular strength, although the muscles can return to pretraining levels.
Read: Beyond size and strength, your muscles simply won't fire the same way they used to because of underuse. What's happening? As muscle fibers realize they don't need to store energy, they will store less glycogen—which leads to something called atrophy (or the shrinking of muscle fibers), explains McCall.
"Your workouts may feel harder after only a week off, but the actual muscle won't go away that fast." A 2015 study from the University of Copenhagen found that it takes only two weeks of skipped workouts to lose significant muscle strength.
By day three, your muscles begin to stiffen, and your heart and lungs are already 5 percent less fit. And by the end the first week, your metabolism slows down and your body fat levels creep up.
"It's more of a cosmetic thing." When you aren't working out regularly, your body composition starts to change. With little physical activity, muscle cells will shrink. With less calorie burn, fat cells will start to expand, making the body look softer.
You're sleep deprived
Exercising when you're running on empty also increases your risk of injury. So if you're exhausted, the best thing you can do for your body is to get a good night of rest and get back in the gym the next day.
Not getting enough physical activity can lead to heart disease—even for people who have no other risk factors. It can also increase the likelihood of developing other heart disease risk factors, including obesity, high blood pressure, high blood cholesterol, and type 2 diabetes.
While it's likely that your body will change — at least a little bit — during a month-long hiatus, the real concern is how your motivation will be affected, says Schneider. Generally, the longer you skip out on your workouts, the more difficult it becomes to feel inspired to get back in there.
Don't forget how long it took you to get to where you are. A day, week, or month off doesn't need to deter you from your fitness goals. Taking a break may be just what you need to get back to your workouts with more energy and enthusiasm.
Even if you watch your diet, your chances of an early death are substantially higher if you sit all day and get no exercise, suggests a new study published in the American Journal of Clinical Nutrition.
It can take just four months of a sedentary lifestyle to put someone back at the beginner level of their workout routine. If that describes you, then a proper mindset will be more important to getting into shape, and staying there, than setting ambitious workout goals.
According to the research of pro bodybuilder Jeff Nippard, the timeframe to get your muscle gains back is typically around half the time you took off. So, if you had a 2-month break from lifting, it might take just a month to get all of your gains back. Took six months off? You'll need three months to gain it all back.
Your muscles weaken and lose bulk including the muscles you need for breathing and the large muscles in your legs and arms. You will become more breathless as you do less activity. If you continue to be inactive you will feel worse, need more help and eventually even simple daily tasks will be difficult.
But exercise is not optional; it is essential, and weight loss is probably the one health benefit it largely fails to deliver. Our bodies are evolved to require daily physical activity, and consequently exercise does not make our bodies work more so much as it makes them work better.
And if you exercise regularly, over time you will gain even more fitness benefits. “At 6 to 8 weeks, you can definitely notice some changes,” said Logie, “and in 3 to 4 months you can do a pretty good overhaul to your health and fitness.” Strength-specific results take about the same amount of time.
Exercise strengthens your all parts of your brain tissue, including gray matter, Dr. Ratley says. This makes your brain more resistant to stress and aging. So if you stop working out, your gray matter may take a hit, potentially setting the stage for problems processing information and thinking critically.
Don't Worry, Your Muscles Remember New research shows that muscles actually have a memory of their former strength level that may last indefinitely. That means that if you've worked out before, it may be easier to get that lost muscle mass back later.
Your aerobic capacity drops by 5 to 10% after three weeks of no exercises, and after two months of inactivity, you'll definitely find yourself out of shape. The good news is that if you're generally an active person even when you don't go to the gym, then it will take longer for you to lose those hard earned muscles.
If you have been inactive for a long time, start with short sessions (10 to 15 minutes). Add five minutes to each session, increasing every two to four weeks. Gradually build up to being active at least 30 minutes a day for most days of the week. Drink plenty of fluids before, during, and after exercise.
If you quit your gym membership and stop exercising regularly, there can be significant changes to your body and health. You could be at greater risk of high blood pressure, high levels of fat in the blood, certain cardiovascular diseases, obesity, depression, and low self-esteem.
Within the first weeks: The body starts to undergo biological changes in muscle size that can lead to weight gain. Over the long-term: Physical inactivity can lead to greater risks for major health problems, from heart disease and diabetes to early death.
Both sleep and exercise are key components of a healthy lifestyle and shouldn't be pitted against each other, Dr. Czeisler said. Sleep is important for workouts, he noted, reducing the risk of injury and allowing muscles to recover from exercise.
And while the occasional long sleep is generally nothing to worry about, oversleeping several days a week could be a sign that something more serious is going on.
The Centers for Disease Control and Prevention (CDC) recommends a minimum amount of exercise—150 minutes of moderate-intensity physical exercise per week, plus muscle-strengthening activities two days per week. But there's no recommended upper limit.