Board-certified clinical exercise physiologist Heather A. Milton tells Shape that stepping into a sauna pre-workout doesn’t activate our muscles in the same way as a more effective warm-up such as stretching. Not only that, but sweating it out in a sauna prior to sweating it out in the gym will have you losing additional body fluid — leaving you susceptible to dehydration.
Additionally, while some research indicates that our blood pressure decreases while in a sauna, a 2019 study found that upon stepping into a sauna, blood pressure and heart rate actually increase to the same degree as a moderate workout on an exercise bike — and there’s no need to tire yourself out prior to a workout. Rather, participant blood pressure and heart rate were found to significantly decrease after leaving the sauna.
Trainers at EOS Fitness reinforce that it’s best to visit a sauna after your workout. Saunas relax the muscles, and relaxed muscles are more susceptible to tearing and injury if you jump right into exercise. Rather, use that relaxation to your muscles’ advantage. Milton elaborates, telling Shape, “it has been suggested that [taking a sauna after a workout] can help with relaxation, the transition from exercise to a more rested state, and perhaps can help with decreasing delayed-onset muscle soreness.”
However, to avoid getting lightheaded, Milton suggests a few minutes of gentle stretches to lower your heart rate before getting into a sauna.