Wednesday, May 2, 2012

Myth: Soreness After Exercise is Caused by Lactic Acid Building Up in Your Muscle

So what is that soreness you get a day or two after working out? It's called DOMS (delayed-onset muscle soreness,) and the belief that it's caused by lactic acid building up in your muscles while you exercise is false. A common belief is that lactic acid build-up in the muscle causes muscle soreness. This is based on the fact that during intense exercise like weight training the muscles make energy for contraction anaerobically (without oxygen), which leads to lactic acid production. This is in contrast to aerobic exercises like walking or jogging that produce energy using oxygen, with little lactic acid build-up. This belief that lactic acid causes DOMS has been shown to be false since any lactic acid that is produced during exercise is cleared shortly after you finish, long before muscle soreness begins.

Instead, that soreness is actually caused by tears in your muscle that occur as you exercise, especially if you're just starting an exercise regimen. It turns out that strenuous exercise leads to microscopic tears in the muscle, which leads to inflammation and soreness. This sounds bad, but the muscle damage is an important step in the muscle getting bigger and stronger. Your muscles are made up of protein filaments that shorten, leading to a contraction. Essentially, as your body repairs those microscopic tears, you're building new, healthy, and strong muscle tissue. This is also the reason why weight training encourages you to increase the resistance or heaviness of your weights as you get accustomed to one level, it's only through this process that you actually get stronger and build more muscle.

If you want to avoid that soreness, start your exercise program slowly and ramp up over time—don't do too much before you (and your body) are ready, and don't feel bad about taking a day off between workouts to recover if you're too sore. Alternatively, switch up your workouts: skip the weights and go for a run instead, for example. After all, an exercise program that makes you so miserable you'll quit after a week won't do you any good in the long run.