Sitting in a hot steam room can help you lose weight, but the weight loss you'll experience is only temporary. As you sweat, your weight will decrease, but you're not actually burning fat or calories; you're only losing water weight. As soon as you rehydrate after using the steam room, your weight will increase. However, many athletes who compete in sports that have weight classes, including mixed martial arts and boxing, use hot steam rooms to help them make weight.
Weigh yourself on a scale before entering the steam room. If you have to make weight at 155 pounds, and weigh 159 pounds, you'll need to lose four pounds in the steam room.
Sit in the steam room until you begin to sweat. Although the steam will create moisture over your entire body, you'll soon feel sweat on your face and other locations, such as your underarms. Remain in the steam room for 20 or 30 minutes, depending on how much weight you have to lose.
Exit the steam room and check your weight on the scale again. If you've lost some weight but still need to lose more, return to the steam room. If you've reached your desired weight, go to the weigh-in quickly and abstain from drinking until you've made weight.