Delayed Onset Muscle Soreness

Delayed onset muscle soreness: the pain that develops 24 to 48 hours after a strenuous workout. We’ve all felt it before, whether it was from running , or simply an activity you’ve never done before. This blog will discuss delayed onset muscle soreness (DOMS), why it happens, what causes it and what is going on in your muscles that causes you to limp down the stairs. Most of the time, I’ll be talking specifically about marathon running, but know that DOMS also occurs after strenuous workouts of which your body is not accustomed.

It was once thought that lactic acid was to blame for DOMS.  It accumulates in the muscles when the amount of oxygen required for the physical activity exceeds the oxygen you’re getting.  It’s your body’s defense against doing any permanent damage to the muscles by overexerting.  Lactic acid doesn’t allow the muscles to work as efficiently, so for example in a marathon, your pace would slow as a result.  Your muscles physically cannot utilize oxygen in a manner that will maintain your pace. Slowing down allows oxygen to get back into your muscles. Once oxygen is back at appropriate levels, your muscles begin to work more efficiently again. Lactic acid IS responsible for pain, but it’s the burning pain you feel as your running. Once you stop running, or whatever the activity, the lactic acid removes itself from your body after about half an hour.  During marathons, I’ve frequently talked with other runners during the miles. Even most veteran marathoners blame lactic acid for their soreness in the days after.

But since lactic acid is removed from the body 30 minutes after you stop exercise, there must be another culprit for DOMS.  The answer, although simple, is not reassuring. The reason you’re sore in the days following a marathon or tough exertion, is due to muscle damage. Using the marathon example, the repeated impact and excessive stress causes microscopic tears within the muscle fibers.  The process by which the muscles get repaired is what causes the pain.  Cells (macrophages and neutrophils) are sent to the damaged area to remove all the dead and damaged cells. Along with this process comes the swelling (another cause for the pain as there is less room within the muscle for it to carry out its’ normal functions)  Once the dead cells are out of the way, new cells(satellite cells) come in and begin to rebuild the muscle fibers. When this is done, the muscle is rebuilt stronger than before. Think of it like this: during an earthquake, a massive amount of destruction occurs (running the marathon), after it’s over cleanup crew come in to begin removing debris from the site (macrophages and neutrophils), once the debris is cleared, the builders can come in and begin rebuilding (satellite cells) and when they do this, they rebuild stronger so it’s prepared for the next earthquake (extreme physical activity).  This is an extremely simplified description of what happens. The process is complex and time consuming (hence the reason you feel pain 24 to 48 hours after the activity).

Some amount of DOMS is necessary for improved muscular fitness.  Since you repair yourself stronger than before, you can now handle that stress again without experiencing as much DOMS.  You can work to prevent severe DOMS by consistently training and gradually increasing intensity and/or duration of your workouts.  Some events, like the marathon, demand so much on the body that not experiencing some DOMS afterwards is nearly impossible. But again, gradually increasing mileage and intensity will help with the degree of pain you feel in the days following the race.