There's nothing like the feeling of getting all hot and sweaty from a good cardio workout. You feel amazing, full of energy, and all revved up on endorphins, so why do people keep asking if you're OK? You catch a glimpse of your sweaty self in the bathroom mirror, and the unnaturally, brilliantly red face staring back takes you by surprise, too. Wait—are you OK?
Your frighteningly scarlet skin may not look the prettiest, but it's no cause for alarm. It's actually just a sign that you're working hard and building up heat. When your body temperature begins to climb, you perspire to keep cool, but it also dilates the blood vessels in your skin to reduce your overall body temp. Your face turns red because warm, oxygenated blood rushes to the surface of your skin, which helps heat radiate off of it and prevents you from overheating.
Go ahead and continue exercising as long as you feel good and have no other symptoms. If you find that your flushed face is accompanied by fatigue, dizziness, sweating more than usual, or nausea, then it could be a sign of heat exhaustion, which is more likely to happen outside on hot and humid days. Working out in a hot room or in higher temps is definitely a risk, so if you experience these symptoms, stop exercising immediately, get inside where it's cooler, loosen up tight clothing (or remove it altogether), and drink plenty of cool water.
To prevent heat exhaustion, make sure to drink plenty of fluids before and during your workout. If you love outdoor workouts, try to exercise during a time of day when temperatures are the lowest, like in the early morning. It also helps to run on shady trails in the woods or on a breezy path near a lake or beach. Here are more tips on how to stay cool when working out in the heat and how to recover after a hot and humid workout.