Why Are My Muscles Sore After Exercise? DOMS Explained (UK 2026)

You try a new class, go a bit harder than usual, or come back after a break. The session feels fine, then a day or two later you wince getting out of a chair. That day-after ache has a name, DOMS, and it is one of the most misunderstood parts of getting fit. Here is a plain, beginner-friendly guide to what it is, what it means, and what actually helps.

What is DOMS?

DOMS stands for delayed onset muscle soreness. It is the tender, stiff, achy feeling in a muscle that turns up a day or so after exercise, rather than during it. The word delayed is the giveaway. If your legs burn while you are still running, that is a different thing that fades fast. DOMS is the slower ache that creeps in the next morning. It tends to be worse after movements your body is not used to, and after eccentric work, which is the lowering part of an exercise, like walking downhill, lowering a weight under control, or the down phase of a squat or a lunge.

What causes DOMS, and is it lactic acid?

First, the myth. DOMS is not caused by lactic acid sitting in your muscles. Your body makes lactate when you work hard, but it clears within about 30 to 60 minutes of you stopping, long before the soreness arrives. Since the ache peaks a day or two later, lactic acid simply cannot be the reason, and researchers set this idea aside decades ago.

The current understanding is that DOMS comes from tiny, microscopic damage to the muscle fibres when you ask them to do something new or harder, especially eccentric lowering work. Your body responds with repair and inflammation, and it is this process, along with the way it makes the area more sensitive, that you feel as soreness. Scientists do not agree on every detail, and some newer research is even looking at the nerves around the muscle, but what is well accepted is that it involves unfamiliar load and recovery, not a build-up of acid. It is a normal, healthy response, and your body adapts so the same movement soon feels easier. That is why the first few sessions of something new tend to hurt the most, then settle as you keep going.

How long does DOMS last?

The timing is fairly predictable. Soreness usually builds about 12 to 24 hours after you finish, peaks in the 24 to 72 hour window, then eases over the next couple of days, and for most people it is gone within three to five days. It should get better day by day, not worse. If it is still climbing or getting sharper after three days, pay closer attention, which we cover below.

Does being sore mean I had a good workout?

This is the big one. No, soreness is not a reliable measure of a good workout or of progress. It mostly tells you that you did something new or unfamiliar, not that the session was effective. You can train hard, get genuinely fitter and stronger, and feel barely any soreness, especially once your body knows a movement. Beginners feel more of it simply because everything is new.

Chasing soreness on purpose is a trap. If you judge every session by how wrecked you feel the next day, you will tend to overdo it and recover poorly. The better markers of progress are steady ones, lifting a little more over time, running further or more easily, turning up regularly, and feeling good doing it. Soreness can come along for the ride, but it is not the goal or the scoreboard.

How do I reduce soreness and recover faster?

There is no magic switch that removes DOMS, but a few sensible habits genuinely help while it passes.

Keep moving gently. Light, easy movement is one of the most helpful things you can do. A gentle walk, an easy cycle or some light mobility work keeps blood flowing and tends to ease stiffness more than sitting still all day. Move the sore muscle, just do not train it hard again.

Sleep, eat and drink well. A lot of recovery happens while you sleep, so aim for a consistent 7 to 9 hours. Eating enough overall, with a reasonable amount of protein through the day, gives your muscles what they need to repair, and regular meals do this for most people without fancy supplements. Drinking enough water across the day helps too.

Warm up and build up gradually. The single best way to avoid being crushed by soreness is to increase things slowly. Add a little load, distance or intensity at a time rather than jumping into a huge session, and warm up properly before you push.

What about ice baths, massage guns and stretching?

Here the honest answer is a shrug. Ice baths, cold showers, massage, foam rolling, compression gear and massage guns are all popular, and some people feel a bit better after them. The catch is that the evidence is mixed and the effects that do show up tend to be small and short-lived. They may take the edge off how sore you feel, but they do not appear to speed up the actual repair. If you enjoy them there is no harm in using them, just do not expect a miracle.

Two common beliefs are worth clearing up. Stretching before or after a session has not been shown to prevent DOMS, so stretch because it feels good and supports your mobility, not as a soreness cure. And massaging to flush lactic acid out is a leftover from the old myth, there is no acid to flush. Gentle movement and a bit of time remain your most dependable tools.

Soreness or injury: how to tell the difference

Most soreness is completely normal, and the skill worth learning is spotting the small number of times when it is something more. As a rule, normal DOMS is a dull, spread-out ache that affects both sides fairly evenly, eases with gentle movement, and gets better each day. An injury tends to be sharp, in one specific spot, often in or around a joint, and it may come on suddenly during a movement. The table below is a quick guide, not a diagnosis.

See a professional, such as your GP or a physiotherapist, if you have sharp or one-sided pain, pain inside a joint, pain that comes on during a movement, noticeable swelling or bruising, if you cannot use the limb normally, or if the pain does not settle within a week or keeps getting worse. This article is general guidance to help you understand normal soreness, not medical advice, and it does not replace a proper assessment. If something does not feel right, get it looked at.

How Edge helps you train without being wrecked

A lot of needless soreness comes from doing too much, too soon, which is exactly what a sensible plan avoids. Edge builds you a fully personalised plan across running, strength, HIIT and mobility, ready in 15 minutes, with your easy and hard days balanced so you progress steadily rather than leaving every session in bits. Easy days stay genuinely easy, and recovery is part of the plan, not an afterthought. If a session lands on a day you are still sore, you can move it, or message a real coach anytime to adjust things around how your body feels. It is one reason more than 18,000 members train with Edge. Making fitness feel good for everyone is the whole idea, and training you can actually keep up with beats the odd brutal week you cannot repeat.

Common questions about muscle soreness

Why are my muscles sore two days after exercise?

That is DOMS, delayed onset muscle soreness. It usually peaks 24 to 72 hours after a new or harder session because it comes from tiny muscle damage and the repair process that follows, not from lactic acid, which clears within about an hour of you stopping.

Is it good to be sore after a workout?

Not necessarily. Soreness mostly means you did something unfamiliar, not that the session was better. You can get fitter and stronger with little or no soreness, so it is not a reliable measure of progress, and chasing it usually leads to overdoing things.

Should I exercise when I am still sore?

Gentle movement is fine and often helps, such as an easy walk, a light cycle or some mobility work. Just avoid training the sore muscle hard again until it has recovered. If the soreness is severe or feels more like a sharp pain, rest it and get it checked.

How do I get rid of muscle soreness fast?

There is no instant fix, but gentle movement, good sleep, enough food and protein, and staying hydrated all help you feel better while it passes. Ice baths and massage tools may take the edge off a little, though the evidence is mixed, so do not rely on them.

When should I worry about muscle pain?

See a professional if the pain is sharp, one-sided, or inside a joint, if it comes on during a movement, if there is swelling or bruising, if you cannot use the limb normally, or if it does not settle within a week or keeps getting worse. Normal soreness is dull and eases day by day.