When your workout goal is muscle gains, it’s tempting to push and push until you achieve the body of your dreams. However, we now know you should rest more if you want to gain muscle. Here’s why.

No Pain, No Gain

The phrase “no pain, no gain” is scientifically accurate. Weight lifting and other heavy-duty exercises cause tiny rips within the muscles. If you had a bunch of tiny cuts on your arm, you would probably develop some scars.

Similarly, muscles almost always scar when they heal. The scar tissue is what causes muscles to appear larger, which is exactly why resting can be the key to bigger muscles.

The Value of Rest

Scientists are still debating it, but most agree that it takes 2-5 days for muscles to heal completely. After each workout, muscles need to complete the ripping and healing cycle in order to see permanent growth.

If workouts intended to gain muscle are not spaced far enough apart, the muscles are being ripped over and over again without having any time to heal. Since the muscles never heal, they never grow. To keep from getting out of the habit of exercising, doctors suggest doing a light activity, such as walking on in-between days.

What Happens When You Don’t Rest?

In addition to stunting growth, it’s dangerous to exercise too often. Walking every day is fine, but the kind of intense workout necessary to gain muscle mass can be problematic if done too often.

Muscles that are constantly being ripped without ever healing fully can become weaker and more susceptible to injury. This also makes exercise more painful, which makes a person more likely to stop. If you want to keep on going hard, you’ve got to know when to go home.