Preparing for an infrared sauna session comes down to a few straightforward steps: hydrate well, eat light, clean your skin, and dress in the right fabric. Each of these makes a real difference in how comfortable you feel and how much benefit you get from the heat. Here’s exactly what to do in the hours leading up to your session.
Hydrate Starting 1 to 2 Hours Before
Drink 16 to 20 ounces of water in the one to two hours before your session. Sip steadily rather than chugging it all at once, which gives your body time to actually absorb the fluid. Infrared saunas cause significant sweating, and starting a session already dehydrated is the fastest way to end up dizzy or lightheaded.
Plain water works, but adding electrolytes gives you an edge. Sweating doesn’t just cost you water. It depletes sodium, potassium, and magnesium. One study in Acta Physiologica Scandinavica found that healthy people had noticeable drops in serum sodium, potassium, and iron after repeated sauna sessions. Sodium helps your body hold onto water and maintain blood volume. Potassium keeps your muscles and nerves firing properly. Magnesium prevents cramping and supports a steady heart rhythm. An electrolyte drink or powder that includes sodium, potassium, magnesium, and calcium covers your bases. If you’re doing a 30-minute sauna, aim to spread about 48 ounces of water with electrolytes across the three hours surrounding your session (before, during, and after).
Eat a Light Meal, Not a Heavy One
Eat at least one hour before your session, ideally one to two hours. Keep it light. Digestion requires a lot of energy and redirects blood flow to your gut, which competes directly with your body’s need to regulate temperature in the heat. A full stomach forces your circulatory system to work double duty, and the result is often nausea, dizziness, or general discomfort that ruins the experience.
Skip anything heavy, fried, or greasy. A piece of fruit, a small salad, toast with nut butter, or a handful of crackers are all fine choices. You want enough fuel that you don’t feel weak, but not so much that your body is still actively breaking down a meal when the heat hits.
Shower and Remove Products From Your Skin
Take a warm shower before you step into the sauna. This does two things: it opens your pores so your body can sweat more efficiently, and it washes away lotions, oils, sunscreen, makeup, and surface dirt that would otherwise sit on your skin and clog those pores. Infrared saunas work by warming your body directly through infrared light waves, so anything coating your skin can act as a barrier between the light and your body.
You don’t need a long shower. A quick rinse with mild soap is enough. The goal is a clean slate so infrared energy reaches your skin unobstructed and sweat can flow freely.
Wear Loose Cotton, Not Synthetic Fabrics
Cotton is the best fabric for an infrared sauna. It doesn’t interfere with infrared rays, it lets your skin breathe, and it absorbs sweat without trapping excessive heat against your body. A soft, lightweight cotton towel or loose-fitting cotton clothing works well.
Avoid PVC, spandex, and workout clothes. Synthetic fabrics prevent airflow, trap too much heat against your skin, and can actually release chemicals into the air at high temperatures. Even cotton should be loose fitting. Tight clothing, including snug underwear, restricts airflow and limits your ability to sweat properly. If you’re using a towel, choose a light one. A heavy towel acts like insulation and reduces sweating, which defeats the purpose.
Skip Alcohol and Stimulants
Do not drink alcohol before a sauna session. Alcohol dilates blood vessels, impairs your body’s ability to regulate temperature, and increases dehydration, all of which become dangerous in sustained heat. Research from Finland has found a growing link between accidental sauna deaths and alcohol intoxication. Even moderate drinking before a session raises your risk of dizziness, fainting, and cardiac events. If you want a drink, save it for well after your session when your body has cooled down and rehydrated.
Caffeine is worth being cautious about too. It’s a mild diuretic, and combined with the fluid loss from sweating, it can push you toward dehydration faster than you’d expect.
Know Your Starting Point as a Beginner
If this is your first time, set the temperature between 105°F and 115°F regardless of your fitness level. Even people who exercise regularly or have used traditional saunas should start here, because infrared heat works differently. It warms your body from the inside rather than heating the air around you, so the sensation and physiological stress are distinct.
Keep your first session to 15 to 20 minutes. A reasonable first week might look like 20 minutes at 110°F, then 25 minutes at 110°F a couple days later, and 25 minutes at 115°F by the weekend. Give your body at least two weeks at these lower settings before increasing temperature or duration. The point isn’t to push through discomfort. If you feel lightheaded or unwell at any point, step out.
Check Your Medications and Medical History
Certain medications interfere with your body’s ability to handle heat. Diuretics, beta-blockers, barbiturates, and antihistamines can all affect sweat rate, temperature regulation, blood pressure, or heart rate in ways that make sauna use riskier. If you take any prescription or over-the-counter medication regularly, check with your doctor before your first session.
Several medical conditions also warrant a conversation with a physician first. These include heart disease, high blood pressure, cardiovascular conditions, circulatory problems, and any condition that impairs your ability to sweat or sense heat. People with pacemakers, defibrillators, or surgical implants should get clearance. The same goes for anyone recovering from surgery, older adults, and people with conditions like multiple sclerosis or diabetes with neuropathy, all of which can disrupt the body’s natural thermoregulation. None of these are automatic disqualifiers, but they change the risk profile enough that a quick medical check is worthwhile.