It’s perfectly normal to experience sore muscles after a marathon. This pain is usually explained by micro tears in the muscles. As a result, the runner temporarily develops a specific gait that is easily recognizable by other runners. Muscle pain usually resolves within a few days, but for untrained runners, full muscle recovery can take up to three weeks. The immune system is also suppressed for a while. Medical research indicates that increasing vitamin C intake in the post-run diet leads to a reduction in sinusitis and other nasal infections, which are quite common, especially among ultramarathoners. Changes in blood biochemistry immediately after a run are so great that they can lead to an erroneous diagnosis of a cardiac disorder.
Due to the stress experienced by the body during a marathon, the kidneys can fail, which leads to the accumulation of toxins in the blood. This is especially dangerous when taking pain medications such as ibuprofen (Advil, Motrin) or acetaminophen (Tylenol). If a runner does not feel the urge to urinate within 4-6 hours after a marathon, despite drinking enough water, a doctor should be consulted.

It is relatively common for runners to notice their foot and knee injuries only after the race is over. Calluses on the feet and toes often begin to hurt only after the end of the distance. For some runners, after a marathon, toenails turn black and even fall off. This should not be a concern, because the nails that come off gradually grow back.

Most sports doctors recommend light exercise for a week after finishing a marathon for faster muscle recovery. The size and type of physical activity during this stage depends on both the runner and his post-run physical condition. Some runners give good reviews for massages received within 24-48 hours of finishing a marathon. Massage received immediately after running, according to marathon runners, is significantly less effective. Trained athletes make their first light run aimed at restoring body functions the next day after the start or even in the evening of the same day.