How Long Does It Take for Muscle Tissue to Deteriorate From Lack of Exercise?

Prolonged inactivity can lead to muscle loss.
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After long periods of training hard, you have the right to be proud of the muscles that start to show themselves. But things happen that can disrupt your routine, and not just for a day or two. A vacation could slow you down for weeks, or an injury could even keep you from the gym for months at a time. It's important, then, to understand how these periods of inactivity can effect your precious muscle gains, and how to pick up where you left off.

Rest Can Be a Good Thing

    First, it's vital to understand that some of these involuntary rest periods can actually help you achieve your fitness goals. For example, if you've been regularly exercising five days a week for a few months, a week or two off would give your body a chance to fully recover from the stress of your workouts. Your muscles grow and repair themselves during rest, so exercising continuously with no break could limit their potential. The time off could also help you to replenish your fuel stores, especially on vacation, when you're more likely to eat a little more than normal. Don't worry, though: You aren't likely to suffer any noticeable loss of muscle over two weeks in which you're still up and moving, according to Shane Paulson, president of the American Society of Exercise Physiologists.

What Is Too Much Time Off?

    Even for the most avid exerciser, though, more than two weeks off is pushing it. At that point you will probably start to lose visual muscle development and strength. The frequency of these breaks is also something to consider. While some elite athletes are in the habit of scheduling a periodic break into their routine, this isn't recommended for someone who doesn't get paid to work out. Since life will likely surprise you with forced breaks, having planned breaks can put you at risk of spending too much time away from your workout. Generally, Pete McCall, an expert exercise physiologist at the American Council on Exercise, recommends only taking these breaks once or twice a year.

Factors to Consider

    As noted, though, an injury can keep you down for long stretches of time. In this case, muscle loss, or disuse atrophy, can happen at an alarmingly rapid pace depending on the condition. Factors that can effect the rate of atrophy include total mobility and which body part was injured. Consider, for example, if you broke your arm. You will still be able to move around, although it will be limited. The amount of movement you're capable of, however, would be much less if you broke your leg. Anti-gravity muscles, those that hold us upright, tend to atrophy much more quickly than their counterparts. For instance, the quadriceps will decrease in size much faster than the hamstrings, in as little as three days.

Getting Back Into It

    Regardless of the reason for your break, you need to gradually reintroduce your body to exercise. You will not be able to lift the same amount or work out at the same intensity as before your time off. If you're recovering from an injury, it will be even more difficult to return to your workout. Consult your doctor before resuming your workout.

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