People sweat at different rates depending on factors like body size, fitness level, workout intensity, temperature, humidity, and even genetics. Instead, your goal during exercise is to replace enough fluid to limit excessive dehydration without drinking so much that you overdo it. Stein adds that it’s surprisingly simple to calculate your sweat rate. If you primarily exercise indoors in an air-conditioned gym, your sweat rate may stay relatively consistent. Knowing your sweat rate and paying attention to how you feel during and after exercise can help you determine what works best for you.