Why does Delayed Onset Muscle Soreness (DOMS) happen with muscles? Why does it take your muscles 12-24 hours to become sore and feel pain, whereas with injuries the pain is instant and doesn’t buildup slowly over the days


I just went to the gym this morning, and now I’m beginning to feel the pain. Afterwards I felt my muscle being fatigued and weak but there was no soreness/pain. Now 12 hours later I’m begging to feel the pain and by tomorrow morning I will be in a world of pain. Why does this happen?

In: Biology

When muscles are required to work harder than they’re used to or in a different way, it’s believed to cause microscopic damage to the muscle fibres, resulting in muscle soreness or stiffness.

DOMS is often mistakenly believed to be caused by a build up of lactic acid, but lactic acid is not involved in this process.

Source DOMS pain is from inflammation, which is need time for immune response to release specific agent (Prostaglandin E2) so we can feel pain. For usual injury, we feel pain directly from stimulation to nerve pain.

Instant pain from “damage” of any sort to the body is caused by nerves, and is evolutionary in nature…to teach us with instant feedback HY we shouldn’t stick our hands in fire, or cut ourselves, or whatever.

Pain from exertion is caused by other root causes listed by others in other posts, and again, are delayed due to evolutionary reasons. If you felt the pain of the exertion instantly from sprinting, you wouldn’t do it, and would have been eaten by whatever was chasing you!

Or, it could be the buildup of lactic acid in muscle tissue due to anaerobic respiration when exercising

You know how when you twist your ankle, it doesn’t swell up and hurt immediately, but takes a few hours? It’s kinda like that.

You don’t exactly have an injury when you exercise, but there’s still damage throughout the muscle. It’s normal, expected damage, though. Your body takes time to send out signals that point out the damage, which call a bunch of cells that act as like a clean up crew to the area. This is called inflammation.

The pain and soreness is how we feel that process – its basically our body’s way of telling us that it’s busy recovering, the same way that immediate pain is a signal to stop and take care of yourself right now.

You gotta remember that pain is not an injury – it’s a message *about* an injury. While you’re exercising, your body is in ‘do stuff’ mode, so it doesn’t tell you to stop and rest. When recovery is happening, your body doesn’t want you to start exercising too soon, so it tells you to chill via soreness.

This is also why you tend to get DOMS specifically when you’re doing stuff your body is not used to doing – ie. When you switch up your exercise routine, or push yourself further than you’re used to. It’s not a sign of an effective workout, but a sign of a workout your body wasn’t expecting/prepared for.