That morning cup of coffee may be an antidote to post-exercise muscle soreness, if preliminary research is correct.

In a small study of female college students, researchers found that a caffeine supplement seemed to lessen the familiar muscle pain that crops up the day after a particularly challenging workout.

Known as delayed-onset muscle soreness, or DOMS, the pain is common in the day or two after a workout that was more intense than normal. Exercise that involves eccentric contraction of the muscles is particularly likely to cause delayed muscle pain.

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The theory is that caffeine eases delayed muscle pain by blocking the activity of a chemical called adenosine, which is released as part of the inflammatory response to injury. Adenosine can activate pain receptors in body cells, explained Victor Maridakis, the study's lead author.

In this study, he told Reuters Health, the pain relief with caffeine was stronger than that from painkillers like acetaminophen (Tylenol) and naproxen (Aleve).¹