Here's What Causes Muscle Soreness After Exercising

body of woman with hands on her back
Learning what causes muscle soreness can benefit you greatly in the long run. A little bit of muscle fatigue is totally normal, but intense or extreme pain isn't a sign of progress.

by Lindsay Tigar

When you begin to develop a workout routine and dive into strength training exercises, you might start to see some (positive!) changes in your body. Not only do everyday tasks become easier, but you may also notice definition in your arms and legs. Of course, along with some of these benefits, you may occasionally notice some other post-workout sensations like muscle soreness.

So, what causes muscle soreness? Let's start by explaining these simple facts: A little bit of muscle discomfort is totally normal; it's a sign the body is healing itself. On the other hand, intense or extreme pain isn't a sign of progress, but rather, a problem. That's why it is important to understand what causes muscle soreness and to be super mindful of your body — so you can keep yourself not only fit but healthy, too!

Why We Get Sore

Delayed onset muscle soreness (DOMS) is the term used to refer to the discomfort many athletes feel following a workout. The exact time this happens varies for everyone, with some reporting soreness as soon as 24 hours after, while others don't feel the effects for 72 hours.

Curious to know what causes muscle soreness, exactly? Well, it's due to tiny tears in your muscle fibers that occur when your body isn't fully prepared or trained for the exertion. As you build strength, you will notice less discomfort— as long as you give your body adequate rest.

If you're feeling a little achy following a workout, Brian Zehetner, director of health and fitness at Planet Fitness, suggests doing low-intensity activities involving the affected muscle groups, as well as enjoying a massage or taking a warm bath.

When Pain Is an Issue

You've probably heard the saying "no pain, no gain" used within the fitness community at one point or another. While you might feel your abs tighten or your arms shake when you're working through a difficult training session, any sort of continued, uncomfortable, or severe pain isn't a sign of progress, but of distress.

"Actual pain is never a good sign during a workout," Zehetner explains. "If you're experiencing this, it usually means you're severely overworking a muscle or you've suffered an injury." Before you push through the discomfort — thinking that you're getting tougher — take a timeout and speak with a personal trainer, professional, or doctor who can assess your symptoms and help you move forward safely.

Staying Healthy

To ensure you're getting the most out of your workout without putting unnecessary stress on your body, Zehetner recommends starting out slow. Even though you may be eager to tackle your fitness goals, understanding how to properly use equipment, perfecting basic movements, and learning aboutwhat causes muscle soreness can benefit you greatly in the long run.

"Keep the workout volume [essentially, the number of sets and reps for a particular muscle group] relatively low and then gradually increase the volume over time," Zehetner suggests. Another way to remain healthy and give your body the best chance at building strength is to stay consistent, he adds, since the best tool for long-term prevention is to keep your muscles active and engaged.

As always, please consult with a physician prior to beginning any exercise program. See full medical disclaimer here.