Last night, I took my very first class in Brazillian Jiu-Jitsu: the not-so-gentle art of folding clothes while someone else is still inside them.
I woke up feeling like I’d been hit by a freight train.
I could barely move this morning! Why does it take more than 24 hours for our muscles to really feel sore after a workout? Why not right away?
Delayed Onset Muscle Soreness, or DOMS, is a poorly-understood, universal phenomenon experienced by athletes of all levels. Simply put: when the body takes on a physical load it’s not used to, we experience a painful soreness, peaking in intensity around 24 to 48 hours after the causal event occurred. DOMS can come from any intense activity we’re not used to – but why doesn’t the pain occur right away? How can we account for that delay, and what does it mean for our athletic performance?
The current thinking is that our nerves, not our muscles, are actually responsible. When we exercise, we create microscopic tears in our muscle fibers. Like with a broken bone, our body does extra repair to the damaged areas, preventing further injury and ultimately increasing muscle strength and volume. In the case of DOMS: the muscle performing the activity gets microscopic damage, but the damage isn’t significant enough to cause pain right away. Individually, microscopic tears in muscle fiber don’t create enough trouble to activate our pain receptors. Instead, it’s the repair process that’s causing the pain.
Our body’s “repair mode” relies on inflammation – itself, a significant cause of discomfort – and the immune system. When our muscles are damaged, they produce a host of signal chemicals and molecules that do activate our neurons, which work to send extra proteins, glycogen, and white blood cells to repair the broken tissue. It’s as if our muscles call for paramedics.
However, the repair process also makes the neurons inside the muscle more sensitive to movement. After all, it’s harder for a muscle to heal if we continue using it. And it’s a slow process. Protein synthesis is one of the more complex biological events, usually taking 24 to 48 hours. In this way, pain becomes the body’s built-in way to restrict our movement during the healing process. After a challenging workout, it’s not that our neurons are sensing more damage to the muscles – it’s that they’re becoming more sensitive to movement after the damage. A plaster cast of psychological origin.
It gets even weirder. If you do an exercise you aren’t used to; you get pretty severe DOMS. But if you do that same exercise 2-3 times a week – even for just a few weeks – the DOMS goes away entirely. You can add significant resistance to the exercise, but the DOMS will never be as bad as it was in the first few weeks. The body just ‘gets used to it,’ even though the same level of damage takes place.
Take a couple of weeks off, and boom: the DOMS comes back.
This further suggests that DOMS isn’t the direct result of damage, but of a temporary modification to how our nerves experience the world, instigated by our muscles themselves and mediated by the brain.
In my own experience, I’ll be fine after a day or two of sleeping and eating well. But when I return to the exercise, I’ll still have pretty extreme DOMS. At that point, it would seem counterintuitive to work out while sore. But within a few minutes, the soreness dissipates significantly. I know I can’t use DOMS as an excuse not to exercise! Unfortunately for new athletes: more exercise is the only thing that’ll make the pain stop. It’s also the very thing that makes it tough to begin moving again, in the first place.
Motion is lotion, as my Dad always said. Turns out; there’s more to that than statement than either of us imagined.
