Direct Answer
A steam room heats you with hot, wet air. An infrared sauna heats you with radiant energy your body absorbs directly. Steam rooms top out around 118°F, but the air is saturated, so your sweat can’t evaporate, and you feel the heat fast. Infrared saunas run with low humidity, so the heat feels gentler and you can breathe dry air. Infrared saunas also deliver light energy in the form of wavelengths, which act on your cells in ways steam can’t.
How a Steam Room Heats You
A steam generator boils water and pipes the vapor into a sealed stall. Steam rooms typically top out around 118°F, according to This Old House.1 Because the stall is sealed and filled with vapor, the air sits at or near saturation.
That’s a lower air temperature than many people expect in a steam sauna, and there’s a reason for it. Wet air delivers heat to your skin far more efficiently than dry air. A steam room at a traditional sauna’s 176°F or higher would be unbearable. Therefore, steam rooms run cooler yet still feel intensely hot.
That effect comes from two things. First, steam condenses on your skin because your skin is cooler than the air. Condensation releases heat directly onto you. Second, saturated air blocks your main way of cooling down. Your sweat beads and drips instead of evaporating, so your body can’t shed heat efficiently.
How an Infrared Sauna Heats You
An infrared sauna doesn’t rely on hot air to warm you. Its heaters emit infrared energy that your skin and tissue absorb, raising your body temperature directly. The air in the cabin stays drier.
Far infrared does most of the warming, and the process starts at the molecular level. Far-infrared energy is absorbed by the vibrating bonds within molecules, per a 2012 review by Vatansever and Hamblin in Photonics & Lasers in Medicine.7 Because your cells and tissue are mostly water, water molecules absorb most of that energy.7 The absorbed energy then spreads to neighboring molecules as they collide, which you feel as warmth.7 The same review notes lab and animal studies where far infrared affected cells even without measurable heating, including changes in cell membranes and mitochondrial activity.7
Sunlighten’s Amplify RED owner’s manual lists an optimal cabin range of 100.4–129°F.6 Research protocols have run in a similar range: a 2023 Biology of Sport trial by Ahokas and colleagues used 43°C (about 109°F).3
Why Humidity Changes How Hard Your Body Works
Humidity isn’t just about comfort. It changes how much strain heat puts on your heart and core temperature.
Your body cools itself mainly by evaporating sweat. In humid air, sweat evaporates slowly or not at all. That means your heart rate and core temperature tend to rise faster for the same time spent in the heat.
A 2015 SpringerPlus study by Mero and colleagues shows the effect. Ten active men used either a far-infrared sauna at 25–35% humidity or a traditional sauna at 60–70% humidity, both at 35–50°C.2 Heart rate after the session averaged 92 beats per minute in the more humid sauna versus 71 in the infrared sauna.2 The authors described far-infrared sauna as a comfortable, low-stress option.2
Newer research points the same way. A 2026 University of Jyväskylä study of 50 adults reported that humidity raised heart rate and core temperature independently of temperature.4 The study was run in collaboration with Harvia, a sauna heater manufacturer, and partly funded by Toyota Motor Corporation.
In practical terms: at a similar temperature, humid heat raises your heart rate more than dry heat, because your body sheds heat less efficiently. People who tolerate heat well may prefer that intensity. People who are new to heat often start with dry infrared heat.
Does Humid Weather Change Your Sauna Session?
Yes, a little, but you can still get the benefits of a session in humid months or climates.
Infrared sauna. An infrared sauna draws in room air, so its humidity rises somewhat on muggy days. Your sweat evaporates a bit more slowly, so the session may feel warmer than usual. Your body still warms from the radiant energy it absorbs, and the near-infrared and red light effects don’t depend on air moisture. On humid days, consider a shorter session or a slightly lower temperature, and hydrate well.
Steam room. A steam room is already saturated, so outdoor humidity changes little inside the stall. What changes is recovery afterward. Stepping out into warm, humid air makes it harder to cool down. Allow extra time to cool off before you move on.
What doesn’t change. No matter the weather, the two work differently. In a steam room, the air is full of moisture, so your sweat can’t dry off your skin. Sweat drying is how your body cools down, so you heat up fast and stay hot. In an infrared sauna, the air stays much drier. Your body warms from the inside, and your sweat can still dry and cool you as you go. That’s why infrared heat tends to feel gentler, and why heart rate rose less in infrared sessions in a 2015 study.2
Beyond Heat: Near Infrared and Red Light
Steam only does one thing: it heats you with wet air. A multi-wavelength infrared sauna does two different things at once.
The thermal effect. Far infrared warms you because water in your tissue absorbs it, as described above.7
The cellular effect. Near infrared and red light work differently. They’re absorbed by cytochrome c oxidase, an enzyme inside your cells’ mitochondria. Researchers place the key absorption bands at about 600–700 nm and 780–1,100 nm, per a 2016 review by de Freitas and Hamblin in IEEE Journal of Selected Topics in Quantum Electronics.5 That absorption triggers a signaling response inside the cell rather than generating heat. Researchers call this photobiomodulation.5
The mPulse Intelligent Sauna delivers near infrared at 880 nm and red light at 650 nm, per Sunlighten internal engineering data. Both fall within the absorption bands described in the 2016 review.5 A steam room only ever produces heat. It has no light-based effect at all.
What Each One Feels Like
Benefits and Drawbacks at a Glance
Humid Heat or Dry Heat: Why People Prefer One or the Other
Why some people prefer humid heat:
- They like intensity. Wet heat feels hot fast, even at a lower temperature.
- Moist air feels soothing to them. Many people enjoy the feel of warm vapor in their nose and throat.
- Their skin feels hydrated. Condensation leaves skin feeling dewy during the session.
- It’s part of a ritual. Steam rooms are a familiar gym and spa routine, often shared with others.
Why some people prefer dry infrared heat:
- It’s easier to breathe. Dry air doesn’t feel heavy in your lungs.
- They can stay longer. Gentler heat makes a longer session easier and more comfortable.
- It’s easier on their heart rate. Heart rate rose less in infrared sessions in a 2015 study.2
- The cabin stays clear. No fog means you can read, meditate, or listen to music.
- They want more than heat. Near infrared and red light add a cellular effect steam can’t.5
- It’s simpler to maintain in their home. No plumbing, drain or mold-prone moisture to manage.
Myth-Check: “You Sweat More in a Steam Room”
It looks that way, but much of the moisture on your skin in a steam room isn’t sweat. Steam condenses on your cooler skin, so you’re also covered in water from the air. And the sweat you do produce can’t evaporate, so it stays visible. In an infrared sauna, dry air lets sweat evaporate as you produce it, so you may look less drenched while still sweating.
Frequently Asked Questions
Is a steam room or an infrared sauna hotter?
A steam room usually feels hotter, even at a lower air temperature. Saturated air stops your sweat from evaporating, so your body heats up faster. An infrared sauna warms your body directly while the air stays drier and easier to breathe.
Why does a steam room feel so intense at under 120°F?
Steam condenses on your skin and releases heat directly onto you. Saturated air also blocks sweat evaporation, which is your body’s main way of cooling down.
Does humidity raise your heart rate in a sauna?
Research suggests that it does. In a 2015 study, heart rate averaged 92 beats per minute after a more humid sauna versus 71 after a far-infrared sauna at the same temperature range.
Is it still worth using a sauna in humid weather?
Yes. Your body still warms from the infrared energy it absorbs, and light-based effects don’t depend on air moisture. Sweat evaporates more slowly on humid days, so a shorter session or lower temperature may feel better.
Can I use water or a vaporizer in my infrared sauna to increase humidity?
It isn’t recommended. Infrared saunas use electric heater panels, not a stove with stones designed to hold water. Adding moisture can damage heaters, electronics, and the wood cabin. Check your owner’s manual before adding water, steam, or a vaporizer.
What’s the difference between far infrared and near infrared?
Far infrared warms you because water in your tissue absorbs it. Near infrared and red light are absorbed by an enzyme in your mitochondria, which triggers a cellular response called photobiomodulation.
Is it easier to breathe in an infrared sauna than a steam room?
Many people find it is. An infrared sauna has dry air, while a steam room is filled with hot, saturated vapor.
Sources cited
- This Old House. “How a Steam Shower Works.” Link
- Mero A, Tornberg J, Mäntykoski M, Puurtinen R. “Effects of far-infrared sauna bathing on recovery from strength and endurance training sessions in men.” SpringerPlus. 2015. Link
- Ahokas EK, Ihalainen JK, Hanstock HG, Savolainen E, Kyröläinen H. “A post-exercise infrared sauna session improves recovery of neuromuscular performance and muscle soreness after resistance exercise training.” Biology of Sport. 2023. Link
- Laatikainen-Raussi I, Mikkola T, Ihalainen JK, Ahokas E. “Temperature and humidity independently influence thermoregulatory responses during Finnish sauna bathing.” Temperature. 2026. Link
- de Freitas LF, Hamblin MR. “Proposed mechanisms of photobiomodulation or low-level light therapy.” IEEE Journal of Selected Topics in Quantum Electronics. 2016. Link
- Sunlighten. Amplify RED owner’s manual. August 2026 (internal document).
- Vatansever F, Hamblin MR. “Far infrared radiation (FIR): its biological effects and medical applications.” Photonics & Lasers in Medicine. 2012. Link
- Sunlighten. “Infrared vs. Steam vs. Traditional Saunas: Which One is Right for You?” Feb. 21, 2025. Link
- Cochrane. “Heated, humidified air for the common cold.” Link
Related Reading
- Infrared Sauna, Traditional Sauna or Steam Room at Home: How to Choose
- Infrared vs. Steam vs. Traditional Saunas: Which One is Right for You?
- Amplify RED Light Saunas
- mPulse Conquer
Ask us! What questions do you have about content, strategy, pop culture, lifestyle, wellness, history or more? We may use your question in an upcoming article!
Like MediaFeed’s content? Be sure to follow us.
This article originally appeared on Sunlighten and was syndicated by MediaFeed.co.
