People have used saunas for thousands of years as a way to relax and potentially promote health. With proper precautions, sauna use is generally safe. Appropriate safeguards mean it is possible for a person with diabetes to enjoy using a sauna.

The term sauna derives from the Finnish word for bathhouse. It generally describes any heating system that induces profuse sweating. Typically, people heat the room to 45–100 °C (113–212 °F).

It is a form of thermal therapy that aims to promote health by eliciting mild hyperthermia to induce a thermoregulatory response.

However, as saunas use high temperatures, they also carry health risks. As such, it is advisable for people living with diabetes to be mindful, regularly check their blood sugars, and be ready to correct them if necessary. They can also consult their diabetes care team for advice.

In this article, we discuss if it is safe for a person living with diabetes to use a sauna and provide tips for safe use.

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Humans have used saunas in different forms for thousands of years, and most people consider them to be generally safe when bathers use them with reasonable precautions.

A 2018 systematic review of sauna bathing did not reveal any serious adverse events but did find reports of mild to moderate heat discomfort, airway irritation, fleeting leg pain, and claustrophobia.

However, people living with diabetes must be mindful of temperature and how it can impact their condition. Evidence notes that heat can affect diabetes in the following ways:

  • Dehydration: People with diabetes may lose water from their body quicker than other people. Not drinking sufficient fluids can raise blood sugars. This may increase the urge to urinate, further causing dehydration. Some common medications, such as diuretics, can also result in dehydration.
  • Difficulty cooling: If a person is unable to keep their blood sugars in their target range, it can damage their blood vessels and nerves. This can affect a person’s sweat glands and make it difficult to cool effectively.
  • Insulin: High temperatures can alter how the body uses insulin. As metabolism increases in hotter weather, the body absorbs insulin quicker. This means blood sugars decrease quicker, which raises the risk of hypoglycemia.

While sauna use may pose some risks for a person with diabetes, sauna bathing is generally safe if a person is able to control their blood sugars.

Additionally, some evidence suggests that saunas may help to prevent hyperglycemia, and passive heat therapy, such as saunas, can help to improve glycemic control.

However, not only is more research necessary, but other lifestyle changes are more likely to be effective and have fewer potential risks, such as hypoglycemia.

It is also advisable to avoid alcohol and any medications that may result in overheating before or after using a sauna. A person can ask their doctor how their condition or medications may impact their health when in a sauna. Other safety precautions can include:

  • not using the sauna for longer than 20 minutes
  • maintaining hydration and drinking cool water after the sauna
  • cooling down gradually afterward
  • avoiding a sauna if feeling unwell
  • leaving if feeling unwell during the sauna

Although saunas generally have a good safety profile, they can pose specific risks for people living with diabetes. People with diabetes can be sensitive to heat, and high temperatures can affect them in the following ways:

Neuropathy

The term neuropathy refers to nerve damage. The American Diabetes Association notes that roughly half of people with diabetes have some form of nerve damage.

Diabetic neuropathy occurs when high levels of fats or sugar in the blood damage nerves, which enable people to feel things and control automatic functions.

As such, nerve damage can result in abnormal sweating and make it difficult for people to regulate their body temperature. Damage to nerves and blood vessels can also increase the risk of heart disease.

High temperatures require the heart to work harder in order to maintain the body’s core temperature. This can put a strain on the heart and increase the risk of potential problems.

Dehydration

Sauna bathing aims to induce profuse sweating. If a person is not adequately hydrated, this can result in dehydration, which is particularly dangerous for individuals with diabetes. This is because dehydration may spike blood sugars and result in hyperglycemia.

High blood sugars can also cause polyuria, which may further increase the risk of dehydration due to frequent urination.

Insulin absorption

To help manage their blood sugars, some people may need to administer insulin. This hormone helps to regulate blood glucose.

To help keep the body cool in higher temperatures, blood vessels widen, which is known as vasodilation. However, as blood vessels expand, it also speeds up insulin absorption. As the body is absorbing insulin quicker, this increases the risk of low blood sugar.

Proponents suggest many health benefits for saunas, but not all of them have backing from scientific data. However, a 2018 systematic review notes regular sauna use may display promise for:

Some research indicates the way the body responds to the heat of a sauna is similar to how it responds to moderate aerobic activity and may provide similar health benefits.

As a precaution, many saunas may ask people to disclose any underlying health conditions. However, if a person is able to control their diabetes, it should be safe for them to use the sauna. Important guidelines for safely using a sauna with diabetes may include:

  • making sure to maintain hydration
  • checking blood sugar levels more frequently than usual, using devices such as continuous glucose monitors
  • being mindful of insulin administration, as the body absorbs it quicker in high temperatures
  • watching for possible signs of hypoglycemia
  • keeping a supply of carbohydrates close by in case of emergencies
  • trying to avoid entering a sauna alone
  • not staying in a sauna for more than 20 minutes
  • reducing the risk of injury or infection and protecting the feet with flip-flops or bath shoes

Many people may find using saunas to be a relaxing and healthful activity, but the high temperatures of a sauna may pose a risk for people living with diabetes.

However, if people with diabetes take suitable precautions and control their blood sugars, they can safely enjoy sauna bathing.

As hot temperatures can affect blood sugars, it is important that a person regularly monitors them and corrects blood glucose levels when necessary. Additionally, people should maintain hydration, use the sauna for an appropriate time, and gradually cool down afterward.

A person can also consult their diabetes care team for further advice and tips.