Eli5: Why do you feel the burn after exercise such as lifting weights or a run after two days rather than immediately afterwards?
In: Biology
There are two kinds of muscle soreness, acute and delayed. Acute you can feel sometimes when training hard.
Delayed is quite common, it’s called delayed onset muscle soreness(DOMS) and we don’t fully know the mechanism for why it happens, but we do know it has something to do with microtears in the muscle tissue which needs healing.
Could be that the healing process is causing the burn and the delay is explained by the time it takes to properly start healing the muscle tissue.
When you exercise, your muscles experience microscopic damage and inflammation. This leads to delayed onset muscle soreness (DOMS), which typically peaks around 48 hours after exercise. It’s believed that the delayed soreness is caused by the body’s inflammatory response to the muscle damage, including the release of chemicals that trigger pain sensations. Additionally, during exercise, your body releases endorphins, which can temporarily mask pain. However, once the endorphins wear off and the inflammation sets in, you start to feel the soreness. So essentially, it’s a combination of delayed inflammation and the temporary masking of pain during exercise that causes the delayed onset of muscle soreness.
Much of the muscle soreness comes from the body directing more blood into the worn muscles. The actual damage is minor but the swelling is adding pressure to that part of your anatomy even while it heals and improves you.
I was just listening to a podcast on this, and basically, we don’t know..
The mechanism of both immediate and delayed muscle soreness aren’t really known it seems like its not actually the same as fatigue and also not necessarily related to other things like micro muscle tears or whatever. Just because your muscle is sore doesn’t mean you can’t exercise or even hit a PR..
I mean I almost think any discussion of soreness should clarify if we’re talking about soreness you experience when you’re new to exercise vs general muscle soreness because I’ve never ever in my entire life been as sore as day 2-3 of the first time I decided to go to the gym (or went back to the gym after a long absence) and we’re talking about a factor of 10x so no, if you don’t normally exercise it doesn’t always feel like this in fact it almost never feels anywhere near this bad
Latest Answers