Why does it take 24 hours for muscles to start hurting after a workout? Why not straight away?


Why does it take 24 hours for muscles to start hurting after a workout? Why not straight away?

In: Biology

This is called [delayed onset muscle soreness](https://en.m.wikipedia.org/wiki/Delayed_onset_muscle_soreness) there are basically 3 theories 1. Micro-trauma and muscle fiber breakdown from the exercise itself that hurts and then causes the muscles to rebuild stronger. 2. Lactic acid buildup that damages muscles in a delayed fashion. 3. Enzyme damage which damages muscles in a delayed fashion.

However 1. Things that are injured usually hurt right away. 2. This doesn’t happen. 3. This isn’t proven.

Basically we don’t know.

Short answer: We don’t know.

Long answer: Delayed Onset Muscle Soreness is poorly understood. We do not know what causes the soreness in the first place, thus we don’t know why it’s delayed. The current working hypothesis is that strong workouts cause microscopic tears, which lead to the soreness when healing.

The hypothesis that lactic acid buildup in the muscles causes the soreness has been rejected, as there is no clear correlation between acid levels and whether the muscles feel sore.

[Further Reading](https://en.wikipedia.org/wiki/Delayed_onset_muscle_soreness)

Stranger still about DOMS…the more days of rest between workouts the more DOMS you seems to get. If I work a muscle group with three or four days rest between workouts, I rarely ever get DOMS regardless how hard I work out. But if I have a week’s rest I will be sore even after only a moderate workout. Strange.

And why for leg day is the day after the day after so much worse? I had my first leg day after 3 weeks because I was recovering from a 12 hour endurance event I did, and all I’ll say is thank god for handicap stalls.

Maybe it’s just me, now that I’m older and not fit anymore, when I work out i actually get sore around 48 hours after.