# Delayed fatigue after exercise **URL:** \ **Category:** Factual Questions\ **Created:** [October 26, 2004, 3:43pm UTC](https://boards.straightdope.com/t/delayed-fatigue-after-exercise/271241 "2004-10-26T15:43:17Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![onion666](https://avatars.discourse-cdn.com/v4/letter/o/eb8c5e/32.png) [@onion666](https://boards.straightdope.com/u/onion666)\ **Post date:** [October 26, 2004, 3:43pm UTC](https://boards.straightdope.com/t/delayed-fatigue-after-exercise/271241/1 "2004-10-26T15:43:17Z")
After fairly strenuous exercise I (and most others) rarely feel the tiredness or muscle aches until 2 days after. Exercise on Saturday, feel fine on Sunday, hurts on Monday. What’s the deal? Is this some primal trait that allowed our ancestors to keep attacking or running away for an extra day? ---
**Author:** ![5que](https://avatars.discourse-cdn.com/v4/letter/5/3bc359/32.png) [@5que](https://boards.straightdope.com/u/5que)\ **Post date:** [October 26, 2004, 3:56pm UTC](https://boards.straightdope.com/t/delayed-fatigue-after-exercise/271241/2 "2004-10-26T15:56:50Z")
It’s called Delayed Onset Muscle Soreness, or DOMS. It’s well know in the training community. > [@](#): > > DOMS is thought to be a result of microscopic tearing of the muscle fibers. The amount of tearing depends on how hard and how long you exercise and what type of exercise you do. For example, activities in which muscles forcefully contract while they are lengthening tend to cause the most soreness. These “eccentric” contractions, as they are called, provide a braking action; they occur in activities such as descending stairs, running downhill, lowering weights, and performing the downward movements of squats and push-ups. > > In addition to microscopic tearing, swelling may take place in and around a muscle, which can also contribute to delayed soreness. Such swelling increases pressure on the neighboring structures, resulting in greater muscle pain and stiffness. Eccentric muscle contractions tend to cause both microtearing and swelling [linky-link](http://www.physsportsmed.com/issues/1999/01_99/muscle.htm) ---
**Author:** ![Boldface\_Type](https://avatars.discourse-cdn.com/v4/letter/b/b5e925/32.png) [@Boldface\_Type](https://boards.straightdope.com/u/Boldface_Type)\ **Post date:** [October 26, 2004, 7:40pm UTC](https://boards.straightdope.com/t/delayed-fatigue-after-exercise/271241/3 "2004-10-26T19:40:49Z")
> [@5que](#): > > It’s called Delayed Onset Muscle Soreness, or DOMS. It’s well know in the training community. > > [linky-link](http://www.physsportsmed.com/issues/1999/01_99/muscle.htm) But that says bugger all about why the soreness is delayed until 2-days post exercise… ---
**Author:** ![5que](https://avatars.discourse-cdn.com/v4/letter/5/3bc359/32.png) [@5que](https://boards.straightdope.com/u/5que)\ **Post date:** [October 26, 2004, 7:58pm UTC](https://boards.straightdope.com/t/delayed-fatigue-after-exercise/271241/4 "2004-10-26T19:58:28Z")
> [@Boldface Type](#): > > But that says bugger all about why the soreness is delayed until 2-days post exercise… The theory is that it’s a sequence of events which take time to develop: #1 Exercise, damage to muscle and connecting tissue #2 Muscle protein breakdown as the muscle repairs #3 Increasing cell inflamation, swelling, and rise in local muscle temperature #4 causing pain receptors to be activated = DOMS The inflamtion and rise in muscle temperature seem to be the critical features. DOMS can occur without muscle damage when there is cell inflamation and swelling. ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [October 26, 2004, 10:19pm UTC](https://boards.straightdope.com/t/delayed-fatigue-after-exercise/271241/5 "2004-10-26T22:19:09Z")
See [here](http://www.t-nation.com/findArticle.do;jsessionid=DDC2A4B927DC41FB554A62BEB0852DDB.ba13?article=161mm) ([part 2](http://www.t-nation.com/findArticle.do;jsessionid=DDC2A4B927DC41FB554A62BEB0852DDB.ba13?article=164mm)) for a pretty detailed explanation of what was known about DOMS in 2001. I don’t think there’ve been any big breakthroughs since then.