Quick answer: Yes, a sauna burns calories—but probably fewer than you'd hope. Sitting in extreme heat raises your heart rate and energy expenditure slightly, with one study recording around 153 calories during a single 10-minute session. Most of the weight you "lose" afterwards is water, not fat. A sauna supports a healthy routine, but it won't replace your training.
So, does a sauna burn calories? It's one of the most common questions we get at Vitru, usually from people hoping the sauna might do the hard work the gym normally demands. We hate to be the bearer of mildly disappointing news, but the truth sits somewhere in the middle. Yes, your body works a little harder in the heat. No, you can't sweat your way to a six-pack while scrolling your phone.
In this guide, we'll explain exactly what's happening to your body in a sauna, how many calories you can realistically expect to burn, and why the scales drop after a session (spoiler: it's not magic). We'll also look at infrared saunas, weight loss myths, and the smart ways to make a sauna genuinely useful for your goals.
How calorie burning works in a sauna
When you step into a hot sauna, your body has one main priority: keeping your core temperature steady. This process is called thermoregulation, and it takes effort.
To cool you down, your heart rate climbs, your blood vessels widen, and you start to sweat. That increased heart rate is the key bit. It's a little like the gentle bump you'd get from a slow walk—your cardiovascular system is doing more work than it would if you were sitting on the sofa. More work means more energy burned.
Here's the crucial part, though. Sweating itself doesn't burn fat. Sweat is your body's cooling system, not a fat-loss mechanism. You can finish a session drenched and feel like you've achieved something dramatic, but the puddle on the bench is mostly water.
Calories burned in a sauna: what to expect
Let's talk numbers, with a healthy dose of realism. A 30-minute sauna session may burn about 100 to 300 average calories, but the calories burned in a sauna vary a lot from person to person, so anyone promising a precise figure is guessing.
That said, research gives us a useful anchor. A 2019 study published in BioMed Research International (Podstawski et al.) estimated that calorie expenditure reached around 153 calories during 10 minutes of dry sauna use in young, sedentary adults, while another study reported about 73 calories in the first 10 minutes. The researchers also noted that calorie burn varies by body weight and session length, and that people with higher body mass and muscle mass tended to burn more calories.
It's worth treating figures like that as a ceiling rather than a guarantee. Several things affect how much you'll burn:
- Body weight and lean mass – larger bodies generally use more energy to stay cool
- Session duration – longer sessions burn more, within sensible limits
- Temperature and humidity – hotter, more demanding conditions raise the effort
- Fitness and acclimation – seasoned sauna-goers may adapt over time
- Hydration status – staying hydrated matters, and dehydration is never the goal
How many calories do you burn sauna bathing compared with exercise?
This is where expectations need a gentle reality check. Compared with exercise, sauna calorie burn is passive and minimal, even though the raised heart rate and sweating during a session helps burn calories.
A rough comparison helps:
- A sauna session – modest calorie burn, similar to light activity, mostly from a raised heart rate
- A brisk 30-minute walk – noticeably more, with the added bonus of building stamina
- A 30-minute strength session – more again, plus muscle building and a longer metabolic effect
The takeaway is simple. A sauna can complement your training beautifully, but it should not replace regular exercise for weight loss. Think of it as the relaxing full stop at the end of a good workout, not the workout itself.
Sauna weight loss: why the scales change after a session
Here's the moment that fools almost everyone. You hop on the scales after a sauna and you're a pound or two lighter. Brilliant, you think. Sauna weight loss is real.
Sadly, that drop is water weight from sweating, not fat. Any weight lost returns quickly once you rehydrate—which you absolutely should—and a session can make you lose fluids at roughly 1–3 litres. So if you think you're shedding pounds, it's really a temporary shift, not a reliable way to lose weight.
If you want a more honest read on your progress, weigh yourself at a consistent time, ideally before a session rather than after, and prioritise drinking plenty of fluids, then drink water and add a few electrolytes after the session. Chasing a lower post-sauna number by skipping fluids is a fast track to feeling rotten, not lean.
Infrared sauna calories burned: is it any different?
Conventional saunas, including Finnish saunas, heat the air around you and typically run at about 150–212°F, while infrared models work differently. Rather than heating the air first, they use infrared light and light waves to warm your body directly and usually operate around 110–140°F.
So what about infrared sauna calories burned? The honest answer is that the calorie burn remains modest, much like a traditional sauna. Traditional saunas provide a quick, intense heat experience, while infrared saunas allow longer sessions because of the lower temperatures. Some reports suggest infrared sessions may burn 250–400 calories in 30 minutes and burn slightly more or slightly more calories than conventional saunas, but results vary and the real-world difference is modest.
For most people, the deciding factor isn't a calorie count. It's comfort, preference, and which one you'll actually use week after week. Consistency beats theoretical numbers every time.
Best ways to use a sauna to support your goals
A sauna earns its keep as part of a healthy lifestyle, not as a standalone tactic. Here's how to get genuine value from it:
- Pair it with training – use it on recovery days or after a workout to support recovery and help you relax, but don’t let it replace regular exercise
- Build up gradually – start with shorter sessions and increase your tolerance over time
- Cool down and rehydrate – replace fluids with water and electrolytes afterwards
- Lean on the indirect benefits – better sleep and lower stress can support the habits that actually drive results, especially alongside a healthy diet and a balanced diet when the goal is sustainable weight loss
This is where a home sauna quietly wins. When recovery sits a few steps from your back door, you're far more likely to use it consistently—and consistency is what makes the difference.
Health benefits of saunas beyond calorie burning
While saunas are not a direct tool for burning calories, their health benefits extend far beyond weight management.
Saunas are particularly effective for muscle recovery, as the heat can improve blood flow and blood circulation, delivering oxygen-rich blood to muscles to relax muscles, reduce soreness, and ease sore muscles after physical activity; some people also use them to manage chronic pain after workouts.
Additionally, saunas are a boon for mental health; the deep relaxation they promote may reduce stress, ease feelings of anxiety, alleviate tension, and support overall emotional well-being. The calming heat has even been linked to enhanced sleep quality and possible help with insomnia, which in turn supports recovery and overall health.
Regular sauna sessions and regular sauna use may also support heart health and cardiovascular health and, in some studies, are linked with a lower risk of dementia.
By integrating a sauna into your routine, you can enjoy a holistic approach to wellness that supports both body and mind.
Sauna safety and who should take care
Saunas are wonderfully relaxing, but a few sensible rules keep them that way:
- Stay hydrated before and after your session
- Skip the alcohol—it's a poor mix with intense heat
- Step out if you feel dizzy or light-headed
- If you're pregnant, have high blood pressure, are monitoring your blood pressure, or are managing another medical condition, check with a healthcare provider or healthcare professional first
Because intense sweating can lead to severe dehydration if you don't replace fluids, drink water before and after your session.
None of this should put you off. It's simply about enjoying the heat with your wits about you.
Frequently asked questions
Does sweating in a sauna mean you're burning fat?
No. Sweating is how your body cools itself, not how it burns fat, and sauna means short-term scale changes are mostly water loss rather than fat burning. Fat loss comes from a sustained calorie deficit, not from how much you perspire, so sweating may lower your weight temporarily but does not cause significant fat loss.
How many calories do you burn in a sauna in 30 minutes?
It varies by body size, temperature, and session length, so there's no universal figure. A typical sauna session lasts around 15–30 minutes, and average calories burned depend on body size, temperature, and duration. People with higher body mass may burn more calories in the same session. Research suggests a single 10-minute dry sauna session can expend roughly 153 calories, but treat that as a rough ceiling rather than a promise. Over 30 minutes you may burn more, though it's still modest compared with exercise.
Is an infrared sauna better for losing weight?
Not meaningfully. Infrared saunas heat your body directly and may help some people burn slightly more calories because sessions can last longer and feel gentler at lower temperatures, but the difference is not meaningful for weight loss. Choose whichever you'll enjoy and use consistently—that matters far more than any small difference in heat type.
Can I use the sauna every day for the health benefits?
Many people use a sauna daily and feel great for it, provided they stay hydrated and listen to their body. Start with shorter, gentler sessions and build up. If you have high blood pressure, another medical condition, or any concerns, check with your healthcare provider first.
Should I sauna before or after a workout?
Most people prefer it afterwards, sitting in a sauna helps the body relax and unwind. Using a sauna for an extended period before training could leave you fatigued and dehydrated, so if you do enjoy a pre-workout warm-up, keep it short and rehydrate well.
The bottom line on saunas and calories
So, does a sauna burn calories? Yes—a small amount, thanks to a raised heart rate and your body working to stay cool. But it's no shortcut to fat loss, and most of that satisfying post-session weight drop is water you'll soon drink back.
Where a sauna truly shines is recovery, relaxation, and better sleep—the unglamorous foundations that help you train harder and stick to your habits. Used well, it's a brilliant supporting act in your wellness routine, not the headline performer.
If you're looking to make sauna part of your weekly recovery at home, explore our outdoor saunas—premium builds designed to help you switch off, recover well, and stay consistent.