August 12, 2015 · Updated Oct 20, 2026

Why Am I Sore After a Workout?

By Chitown Trainer Team

The soreness you feel a day or two after a hard or new workout has a name, a predictable timeline and a few remedies that actually help. Lactic acid isn't one of the causes.

This article is general information, not medical advice. Talk with your doctor before changing medications or starting a new program.

The short answer

Muscle soreness that shows up the day after a workout is called delayed onset muscle soreness, or DOMS. It usually starts 12 to 24 hours after a harder or unfamiliar workout, peaks between 24 and 72 hours, and fades within about a week (Mizumura and Taguchi, 2016). It isn't caused by lactic acid, and it isn't a sign that you did something wrong.

What is delayed onset muscle soreness?

DOMS is the tender, stiff feeling in muscles you worked hard, especially when the exercise or the amount of work was new to you. The muscle hurts when you press on it, stretch it or use it, so stairs and getting out of a chair can feel harder for a day or two.

The main trigger is the lowering, or eccentric, part of a movement: the way down in a squat, lowering a dumbbell after a curl, or walking downhill (Mizumura and Taguchi, 2016). That's why a new strength routine or a hike with a long descent can leave you sorer than a harder workout you already do every week. The exact mechanism is still being studied. Current research points to changes in the muscle after these unaccustomed lengthening contractions that make its pain sensors more sensitive for a few days.

A typical timeline:

12 to 24 hours after the workout: soreness starts.

24 to 72 hours after: it peaks.

Within about 7 days: it's gone.

Why it isn't lactic acid

Lactate, often called lactic acid, rises during hard exercise, so it gets blamed for next-day soreness. The timing rules it out: lactate is back to resting levels within about an hour after exercise, long before DOMS begins (Mizumura and Taguchi, 2016). Your muscles also use lactate as fuel, so it's part of normal energy production rather than waste that sits in the muscle.

The burning feeling during a hard set is a separate sensation that eases soon after you stop. DOMS arrives later.

Why the second workout hurts less

Repeat the same workout a week or two later and you'll usually be far less sore. This is called the repeated bout effect: one session of an unfamiliar exercise protects the muscle against the same soreness next time, and the protection can last up to several months (Nosaka and Aoki, 2011). It's why the first week of a new program tends to be the sorest, and why regular training feels easier than occasional hard sessions.

What helps, ranked by evidence

No recovery method makes DOMS disappear, and most have small effects. Here's what the research shows, strongest first:

Massage: the most effective method for reducing soreness and perceived fatigue in a 2018 meta-analysis of 99 studies (Dupuy et al., 2018).

Light activity and compression garments: both also reduced soreness in the same analysis (Dupuy et al., 2018).

Foam rolling: a small reduction in muscle pain after rolling (Wiewelhove et al., 2019).

Cold water immersion: may reduce soreness, but the studies behind it are low quality (Bleakley et al., 2012).

Stretching: doesn't reduce soreness by an amount people notice, whether you stretch before or after exercise (Herbert et al., 2011).

Anti-inflammatory painkillers: did no better than placebo in a 2021 meta-analysis, though the evidence is very low quality (Nahon et al., 2021). Ask your doctor or pharmacist before taking them for workout soreness.

The most reliable approach is prevention. Start new exercises with lighter weights and fewer sets, then build up over the first few weeks so the repeated bout effect works in your favor.

Should you train while you're sore?

Mild soreness usually isn't a reason to skip a workout, and light activity is one of the things that helps. If you're very sore, train a different muscle group, go lighter, or spend the session on easy movement and technique until it eases. Save heavy or explosive work for the sore muscles until the soreness has mostly passed.

When it isn't normal soreness

Normal DOMS is a dull, tender ache in muscles you worked, and it improves day by day. Stop exercising and get medical care right away if you have muscle pain far worse than you'd expect from the workout, feeling unusually weak or tired, or dark, tea- or cola-colored urine. These can be signs of rhabdomyolysis, a serious condition in which damaged muscle releases its contents into the blood (CDC/NIOSH).

See a doctor or physical therapist if the pain is sharp or in a joint, comes with swelling or bruising, started suddenly during a specific movement, or isn't improving after a week. Those point to an injury rather than DOMS.

FAQ

How long does muscle soreness last after a workout?

Usually up to about a week. It starts 12 to 24 hours after the workout, peaks at 24 to 72 hours and then fades (Mizumura and Taguchi, 2016).

Is being sore a sign of a good workout?

Not necessarily. Soreness mostly reflects how new the exercise was, especially the lowering part of each move. As your body adapts, the same workout leaves you less sore, so less soreness over time is normal and not a sign that training has stopped working.

Does stretching prevent soreness?

No. A Cochrane review found that stretching before or after exercise doesn't reduce soreness by an amount people would notice (Herbert et al., 2011). Read more in should you stretch before or after a workout.

Does drinking more water help sore muscles?

Drinking enough water matters for exercise in general, but we couldn't find a study showing that extra water shortens muscle soreness. Massage and light activity have better evidence.

Train with us

A good trainer plans your first weeks so new exercises build up gradually, which keeps soreness manageable while you get stronger. Chitown Trainer's certified trainers come to your home, your building's fitness center, your office or a nearby park. Read about in-home personal training, see the areas we serve, or book a free consultation.