Is Lactic Acid Buildup Really What Causes Muscle Soreness After a Workout?

We’ve all been there. You head to the gym after taking a brief hiatus, and by the time you finish your workout, you feel great. But then, by the time you roll out of bed the next day, you’re sore, your muscles feel tight and maybe even a little swollen.

We’ve come to know this phenomenon as delayed onset muscle soreness (DOMS) — and with DOMS comes the age-old myth explaining it to us: “It’s just lactic acid buildup. You’ll be good to go in no time.”

The issue is that this myth, like all good myths, is rooted in a fascinating bit of reality. But when you look deeper, you find out that your muscle soreness isn’t due to what’s being portrayed as its obvious culprit in this myth.

What’s lactic acid?

Lactic acid is a byproduct that’s produced during intense exercise when the body breaks down carbohydrates for energy. This process, called glycolysis, doesn’t require oxygen, making it an anaerobic process. When the body breaks down glucose anaerobically, a substance called pyruvate is produced. Normally, pyruvate is then oxidized to produce more energy, but when there’s a lack of oxygen, lactic acid is produced instead.

Lactic acid is often blamed for causing the muscle pain you experience during or immediately after a workout. If your workout has ever left your muscles burning almost instantaneously, lactic acid is the most likely cause.

What’s actually causing the muscle soreness?

If your delayed muscle pain isn’t from lactic acid, though, what’s actually causing it?

According to Dr. David Lintner, an orthopedic sports medicine surgeon at Houston Methodist, the muscle soreness that follows physical activity is related to damage occurring in the muscle, specifically the small microscopic tears in the muscle fibers. “When you exercise, you’re putting stress on your muscles, causing these tiny tears,” explains Dr. Lintner.

In response to these tears, an inflammatory process begins, and you may start noticing that your muscles are sore and stiff the next day, which can often last between 24 and 72 hours. The scientific term for this is DOMS.

Dr. Lintner goes on to explain that while inflammation plays a key role in the entire muscle repair process, causing soreness, its role continues to be analyzed and fully understood. However, a common misconception is always linking this soreness to lactic acid buildup.

Are there ways to relieve muscle soreness?

There’s no magic remedy for preventing DOMS, but there are a few ways you can help ease the pain:

• Stretch it out: Gentle stretching can help reduce muscle tension and increase your flexibility, which in turn may help alleviate soreness.
• Stay active: Light activity can actually help relieve soreness better than resting.
• Apply heat: A warm bath can help improve blood flow, which may reduce soreness and tightness.
• Use the best joint pain relief cream: Finding the best joint pain relief cream available can also help with soreness, especially when applied directly to the affected area.

Despite what’s causing your muscle pain, it’s essential to give your muscles time to recover, and over-the-counter pain relievers and creams meant to target joint and muscle pain can provide you with some comfort.