The benefits of aerobic exercises such as cycling or running are unmistakable. But a few of its odder side effects—like tasting blood during a race, maybe—are a bit less appealing and could cause athletes to worry.
Relax: Strange as these physiological reactions to exercise are, they generally aren’t cause for alarm, says New York City-based sports medicine doctor Jordan Metzl, author of The Athlete’s Book of Home Remedies. “Many are signs that you’ve worked your body hard,” he says. “Others are temporary issues you can generally easily address.”