You're asking and I'm answering.
"Hey Fit! My gym just got a makeover and there is now a sauna in the locker room. I have never used a sauna but I have seen them on TV, where you go in in your towel and just sweat. So, I wanted to know what are the benefits for using a sauna? Also I see people go in there right after working out and some of them go in fully clothed (even in sweats)! If you could reply, I would really appreciate it!"
This is a great question, and what a nice perk that your gym now has a sauna. I love saunas and to see why read more.
There are many benefits to using a sauna, and post workout the main one is to relax and congratulate yourself for a job well done. It is nice heat treatment for your muscles that just worked hard. Since the heat of the sauna makes you sweat, it is also a good way to detox, since sweating is one way to remove impurities from the body. Sweating in a sauna or steam room increases the circulation to the skin by dilating the blood vessels, which also reduces blood pressure. Make sure you drink enough water while using a sauna, especially after exercise, because you don't want to become dehydrated.
If it is acceptable to use the sauna nude, make sure to sit on a towel for hygienic reasons. It is good etiquette to shower before entering a sauna to get rid of any body odor (stink you worked up while working out) or smell of chlorine (I love to sauna after swimming laps). I am not sure why people are wearing sweats into the sauna since this will just increase the amount that they sweat and sounds uncomfortably hot. If they are wearing clothes in the sauna to promote weight loss, they are only losing "water weight" which they will regain as soon as they drink.
Since saunas are used for relaxation keep chatter to a minimum and make room for new comers if the sauna is crowded. Meaning if you are lying down, sit up to create space.
Many people like to finish their sauna experience with a cold shower or plunging into a cold pool. This is exhilarating, but can make your heart race. So do this with caution. If you have high blood pressure or a heart problem, be sure to check with your physician before going to a sauna or steam room.
Have fun and don't forget to replenish lost fluids.