# Do saunas burn significantly more calories than just sitting idly?

There are a bunch of sites claiming this, with the most disparate theories: that saunas directly melt fat, that saunas burn calories because your body needs to maintain the normal temperature, that saunas increase your metabolism, that they make your heart work harder...

I also found a ton of suspicious pages like this one.

While there are a million theories, has anyone measured if any extra calories are burnt at all? If so, does sitting idly in a sauna burn significantly more calories than sitting idly elsewhere?

• Note: this question was asked as part of the "topic of the week" initiative to raise our questions per day stat. Please contribute some great questions! Commented Mar 18, 2012 at 20:48

Sauna makes your heart work harder

Sauna definitely increases heart rate ([1] and [2])

Does sauna makes you burn calories the same as exercise ? No.

The most accurate method of measuring calorie burn is through VO2 testing ... Combustion, which turns the fuel you receive from food into energy, needs oxygen. Because there is a direct relationship between how much oxygen you use and how much energy you burn, by measuring the oxygen to carbon dioxide exchange through VO2 testing, you will get a fairly precise gauge of how many calories you're burning.

eHow "How Heart Rate Monitors Calculate Calories Burned"

This study has show following results:

VO2 on exercise (ml/min) 1269,4 +/- 426,1 VO2 on suana (ml/min) 236,9 +/- 42,7

Oxygen update in suana was much less then during exercise.

What about sauna and sitting ?

Let's say sitting requires 1 MET, then for 120 kg person would intake about 120 ml / min. Walking for the same person (120 kg) would be 120 kg * 3 ml / min kg = 360 ml / min

So, sauna makes your body burn more calories than sitting, it's can't be compared to exercises.

• You lost me in the last part. Do you burn more calories than sitting? How many more? Commented Mar 24, 2012 at 14:09
• @Sklivvz Sitting: ~120 ml/min, Sauna: ~240 ml/min, Walking: ~360 ml/min, Exercise: ~1270 ml/min. Calorie burn depends on body statistics. Commented Apr 4, 2012 at 5:45
• But it's quite possible the 120 ml/min increase in VO2 value doesn't do much for the calorie burn. I'm not familiar enough with the topic to do the calculations. There are some online calculators for this type of stuff but it seems they don't take the values in the form provided in this answer. Commented Apr 10, 2012 at 5:50