Your sessions must be for only 5 to 30 minutes long. But how long you can safely use the sauna or steam room depends on how accustomed you are to it, or how hot the sauna or steam room is. If you’re feeling dehydrated because you’ve probably been back for a long run, it’s not good to spend a long time in the sauna. But if you’re well hydrated and feel fine, you can stay a little longer. It’s also common to step out of the sauna or steam room for frequent breaks, so leave whenever you feel thirsty. It’s best to use sauna or steam room regularly for many health benefits (several times a week, if you can), start a trip to the spa for as many as five or 10 minutes to see how well you can handle it.