Should you work out when you're sore?

Question: I'm still sore from yesterday's workout. My boyfriend says that to continue building muscle, I should keep working out until the soreness goes away. I say it's more beneficial to take a day of rest and then workout tomorrow. Who's right?

Expert Answer:
First of all, are you sore from strength training, or from cardio? Are you new to either of these types of exercise? It's common for beginners to experience muscle soreness that lasts for a week or two. Yes, you should keep working out even though you are sore, but your boyfriend isn't exactly right in what he is telling you.

Muscle soreness has two primary causes. The first soreness you experience happens during your workout ("the burn") and should subside within a couple of hours. This is caused by lactic acid production. When you are training and your muscles are not getting enough oxygen (anaerobic glycolysis), lactic acid builds up. You can break down lactic acid by continuing to move and by doing light aerobic exercise (such as walking) after your workout. This is why cool-downs are so important, especially for beginners. The longer you cool down, the faster that lactic acid will be broken up and removed from the body.

The type of muscle soreness you are experiencing, up to a day or two (and sometimes even three) after your workout is known as DOMS (Delayed Onset Muscle Soreness). DOMS is caused by microscopic tears inside the muscles, resulting from weight-training or fully exhausting the muscles during cardio. This is normal. Again, beginners will be more sore and usually for longer, but if you really worked as hard as you should have during a weight-lifting session, you should be somewhat sore for the next day or two.

This is where rest comes in. You absolutely must rest the muscles you worked for 1-2 days after a workout. So, if your boyfriend meant that you need to keep lifting anyway, he was wrong. Take at least one day off between sessions, and if you are still very sore, take 2 days off. (This means from lifting, not from all exercise such as cardio). If you don't let your muscles recover and repair, they will continue to break down and you will actually get weaker.

To help prevent soreness in the future, and alleviate some of it now, be sure to: 1. Always warm-up for 5-10 minutes and cool-down for at least 5 minutes 2. STRETCH!! Stretch after a warm-up, during your workout, and after you are done. Only stretch when your muscles are already warm from some kind of light activity. 3. Stay active. The more your muscles move, the faster they remove that lactic acid build-up. 4. Have your boyfriend give you a massage for all of the hard work you put in at the gym.

Exercise Extra: Research shows that engaging in lower intensity exercise after a strenuous workout session may be more beneficial than resting completely.