why does it take >24 hours to “feel” a hard workout?


why does it take >24 hours to “feel” a hard workout?

In: Biology

It’s called DOMS, or delayed onset muscle soreness. People often reach peak soreness the day after a workout, or even the day after that. We aren’t entirely sure about the specifics what drives muscle soreness. People historically said “something something lactic acid something”, but that’s probably not what is really doing on. Eccentric exercise seems to cause more soreness than concentric.


Kinesiologist here, while you may hear lactic acid as the cause, and even my sisters biology professor didn’t know but agreed with her, the actual cause is micro tears in your Z bands in your muscles. The reason for 24ish hours is not well known although I haven’t been in school in 5 years or so. But personally for me, my legs seem to take the longest to feel sore while sometimes I feel soreness within a few hours. I personally also notice if I workout regularly, sleep and eat good, soreness is never really a problem. Good recovery will limit soreness which is why steroids are also a giant advantage in athletes, among other reasons. Also to add on, this doesn’t mean you can’t get latic acid poisoning but it’s rare in humans and can be deadly.

Micro tears in your muscle fibers is definitely the best explanation for soreness. Lactic acid is what causes the burning feeling when your muscles just can’t take anymore during a workout. To answer your question of why it can be delayed like DOMS (delayed onset muscle soreness) which someone has already mentioned I don’t know why it’s so delayed. I do know that it’s more delayed for those who haven’t exercised those muscles in a long time. Perhaps the inflammatory process is responsible for it though

Interestingly enough, this is impossible to answer as there is no conclusive answer as to why. Really.

Which seems strange as “new movement” seems like one of the most basic things in human existence, but why the pain appears later, and only initially, but not repeatedly, even from overload (This is called the RBE for Repeated Bout Effect – the fact that you can strain the muscles even harder in the future, tear them up even more, but to no DOMS effect as long as the muscle is regularly undergoing that stress), still isn’t conclusive.

There are certainly existing factors, inflammation, stretching, or the use of, underused muscle fibres, etc – but again, *WHY* that pain appears is still unclear.


“*The exact cause of DOMS is unknown. Like most relatively minor aches and pains, understanding DOMS is an extremely low priority in medical science. That’s surprising when you consider the impact DOMS has on elite athletes — a group of people whose performance is collectively worth trillions of dollars, and obsessively optimized, seemingly sparing no expense. You’d think this topic, at least, would get more scientific attention. And yet we don’t really know why DOMS happens.*”

Footnoted sources:

Parr JJ, Borsa PA, Fillingim RB, et al. Pain-related fear and catastrophizing predict pain intensity and disability independently using an induced muscle injury model. J Pain. 2012 Apr;13(4):370–8.

Pyne DB. Exercise-induced muscle damage and inflammation: a review. Aust J Sci Med Sport. 1994 Sep-Dec;26(3-4):49–58.