Kaps says dopamine, oxytocin, serotonin, and endorphins (that's where the acronym DOSE in Higher DOSE comes from) are all released during an infrared sauna session, from the infrared lights and just knowing you're doing something good for yourself. At Higher DOSE, they let you listen to your own music and encourage taking selfies to make it a real experience. Dr. Kogan suspects the infrared lights could have a positive "healing effect," but that hasn't actually been studied. "How this happens is unknown, because no one has been able to measure the actual levels of serotonin or cortisol before and after treatments," she says. One study confirmed that heat makes people feel relaxed . Bottom line: You don't have to go to an infrared sauna to relax and feel happy, but it just might tide you over until it's warm out again.