One infrared sauna session and blood sugar: no help
Twelve people with type 2 diabetes sat in an infrared sauna, heated on one day and not on another, then drank a sugar test drink. Heat did not improve how they handled the sugar.
The short version
Twelve older adults with type 2 diabetes each sat in an infrared sauna for 40 minutes on two days, once heated to 60°C and once at room temperature, in random order. Straight afterwards they drank a standard sugar drink and had their blood tested for two hours. After the heat, blood sugar rose slightly more, not less, and insulin and insulin sensitivity were the same. One session in 12 people cannot say what regular sauna does, but it gives no support to the idea of a quick blood sugar benefit.
Keep in mind
One session in 12 people, tested straight after the heat. It says nothing about regular sauna over weeks.
What they found
The heat worked as intended: core temperature reached 38.0°C, against 36.6°C on the control day.
Blood sugar after the drink rose slightly more after the heat: an area under the curve of 17.7 against 14.8 mmol/L over two hours.
Insulin levels and insulin sensitivity did not differ between the two days.
What this means for your practice
A single sauna session is not a way to handle blood sugar after a meal. If you have diabetes, ask your doctor before using a hot sauna.
This does not establish a sauna routine to follow.
Methods and limitations
What the researchers did
The researchers recruited 12 adults with type 2 diabetes, on average 69 years old. Each came in on two days, in random order.
On one day they rested in an infrared sauna heated to 60°C for 40 minutes; on the other, in the same cabin at 21°C. Straight afterwards they had an oral glucose tolerance test: a sugar drink, with blood taken over two hours.
Blood sugar, insulin and an index of insulin sensitivity were compared between the two days.
How much can this tell us?
The crossover design is a strength: each person is compared with themselves, which suits a small study.
But it tested one session, with the sugar test straight after, when the body is still busy cooling down. Regular sauna over weeks could act differently, and this trial does not test that.
Infrared cabins are milder than a Finnish sauna. Twelve people, mostly men, is a very small group.
What makes it useful
- Randomized crossover: each person their own comparison
- A standard sugar test with blood measures
What limits it
- Very small: 12 people
- One session, tested straight after
- Infrared cabin, not a Finnish sauna
Where this study fits
Where this study fits
We score claims, not single studies. This one is part of the evidence for:
Heat helps control blood sugar. Not supported
Low certaintyNo effect foundBody signals
Read the original
Schenaarts L, Hendriks FK, Fuchs CJ, Sluijsmans WE, Snijders T, van Loon LJ. A Single Sauna Session Does Not Improve Postprandial Blood Glucose Handling in Individuals with Type 2 Diabetes Mellitus: A Cross-Over, Randomized, Controlled Trial. Exp Clin Endocrinol Diabetes. 2024;132(11):622-630.
DOI 10.1055/a-2406-4491 · PubMed 39209309