10 Health Risks Associated With Sauna Use: What Science Says About Sauna Safety

Sauna bathing has become increasingly popular as part of modern wellness, relaxation and recovery routines. From traditional Finnish saunas to infrared saunas, people use heat exposure to relax, unwind and support their overall well-being.

Scientific research has associated regular sauna bathing with potential cardiovascular benefits. However, sauna use is not entirely risk-free. Excessive heat exposure, dehydration, prolonged sessions and certain underlying medical conditions can create health risks.

Understanding these risks can help you enjoy sauna sessions more responsibly.

In this guide, we explore 10 potential health risks associated with sauna use, the scientific research behind them and practical ways to stay safe.

1. Dehydration

Sweating is a natural response to heat exposure. During a sauna session, the body loses water through perspiration. Longer sessions and higher temperatures can increase fluid loss.

If lost fluids are not replaced, dehydration may develop.

Common warning signs:

• Excessive thirst
• Dry mouth
• Headaches
• Dark-coloured urine
• Dizziness and fatigue

How to reduce the risk:

Drink sufficient water before and after sauna sessions. Avoid prolonged exposure, particularly when you have already been sweating from exercise.

Innie & Outie recommendation: A Double Wall Stainless Sauna Water Bottle is a practical accessory for keeping drinking water nearby during your wellness routine.

2. Heat Exhaustion

Heat exhaustion occurs when the body struggles to regulate its temperature during excessive heat exposure.

Prolonged sauna sessions can increase the risk, particularly when someone is dehydrated or unaccustomed to high temperatures.

Warning signs include:

• Heavy sweating
• Weakness
• Nausea
• Headaches
• Dizziness
• Increased thirst

How to reduce the risk:

Leave the sauna immediately if you experience these symptoms. Move to a cooler environment, rest and rehydrate. Seek medical attention if symptoms persist or worsen.

3. Heatstroke and Dangerous Overheating

Heatstroke is a serious medical emergency that occurs when the body's temperature regulation fails.

Although uncommon, excessive heat exposure can contribute to dangerous overheating.

Warning signs include:

• Confusion
• Altered mental state
• Loss of consciousness
• Seizures
• Very high body temperature

How to reduce the risk:

Never attempt to push through extreme heat discomfort. Stop your session immediately if you feel unwell. Confusion, seizures or unconsciousness require emergency medical assistance and immediate cooling.

4. Low Blood Pressure and Dizziness

Heat causes blood vessels to widen, a process known as vasodilation. This can lower blood pressure.

Some people experience light-headedness, particularly when standing up quickly or leaving the sauna.

Possible symptoms:

• Dizziness
• Blurred vision
• Feeling faint
• Weakness

How to reduce the risk:

Stand up slowly when leaving the sauna. People with low blood pressure or those taking blood-pressure medication should consult a healthcare professional before using a sauna.

5. Fainting and Accidental Injuries

A sudden drop in blood pressure can cause fainting or loss of balance.

A 2023 study published in Injury examined 209 patients with sauna-related injuries. Slips and falls were the most common causes, followed by dizziness and fainting.

Injuries included fractures, wounds, head injuries and burns.

How to reduce the risk:

• Exit the sauna slowly.
• Avoid slippery flooring.
• Use appropriate non-slip footwear outside the sauna.
• Sit down immediately if you feel dizzy.
• Avoid sauna sessions when intoxicated.

Innie & Outie recommendation: A Non-Slip Steam Room Mat can be a useful addition to compatible steam-room areas to help maintain a more secure walking surface. Follow the product's placement and maintenance instructions.

6. Cardiovascular Stress

Sauna exposure increases heart rate and changes blood circulation as the body attempts to regulate its temperature.

For many healthy individuals, this response is generally well tolerated. However, people with unstable cardiovascular conditions may experience additional strain.

Individuals with unstable angina, recent heart attacks, severe aortic stenosis or poorly controlled cardiovascular conditions should seek medical advice before using a sauna.

How to reduce the risk:

Avoid sauna sessions if you are experiencing chest pain, unusual breathlessness or other concerning cardiovascular symptoms.

A healthcare professional can help determine whether sauna bathing is appropriate for your condition.

What does research say?

A 2015 study published in JAMA Internal Medicine followed 2,315 middle-aged Finnish men for a median of 20.7 years. More frequent sauna bathing was associated with lower risks of sudden cardiac death and fatal cardiovascular disease.

However, this was an observational study, not proof that sauna use prevents cardiovascular disease.

7. Pregnancy-Related Risks

Pregnancy changes the body's temperature regulation and cardiovascular demands.

Excessive heat exposure, particularly when it significantly raises core body temperature, may pose risks to fetal development.

The American College of Obstetricians and Gynecologists advises avoiding sauna and hot-tub use during early pregnancy because of concerns about elevated core body temperature.

How to reduce the risk:

Pregnant individuals should consult their obstetrician before using traditional or infrared saunas and follow individual medical advice.

8. Male Fertility and Sperm Quality

Repeated exposure to high temperatures may temporarily affect sperm production and sperm quality.

The testes normally remain at a temperature slightly lower than core body temperature. Frequent heat exposure may interfere with this temperature regulation.

What does research say?

A 2013 study published in Human Reproduction examined 10 healthy men who used a Finnish sauna twice weekly for three months.

Researchers observed reductions in sperm count and motility. These changes reversed after sauna exposure stopped.

The study was relatively small, so its findings should not be interpreted as proof that normal sauna use causes permanent infertility.

How to reduce the risk:

Men trying to conceive may wish to discuss frequent sauna use with a healthcare professional, particularly if they have fertility concerns.

9. Alcohol-Related Complications

Combining alcohol consumption with sauna bathing can increase health risks.

Alcohol can impair judgement, affect blood pressure and contribute to dehydration. Heat exposure can further increase the risk of dizziness, fainting and cardiovascular complications.

How to reduce the risk:

Avoid alcohol before and during sauna sessions. Never use a sauna while intoxicated.

10. Burns and Skin Injuries

Sauna environments contain heated surfaces, including benches, heaters and other accessories.

Direct contact with excessively hot surfaces can cause burns. Slipping, falling or losing consciousness in a hot environment can also increase the risk of injury.

How to reduce the risk:

• Avoid touching sauna heaters.
• Use a towel when sitting on benches.
• Do not place skin directly against extremely hot surfaces.
• Avoid lying down in a sauna if you feel unwell.
• Follow the manufacturer's safety instructions.

Innie & Outie recommendation: A Handmade Wool Sauna Hat is a traditional sauna accessory that some users prefer for comfort during heat exposure. It should not be considered protection against overheating or heatstroke.

How to Make Your Sauna Experience Safer

Sauna bathing can be an enjoyable part of a wellness routine when approached responsibly.

Here are eight practical precautions:

1. Start with shorter sessions and increase gradually according to comfort.
2. Drink water before and after sauna use.
3. Avoid alcohol.
4. Leave immediately if you feel dizzy, nauseated or unwell.
5. Allow your body to cool down after each session.
6. Keep sauna surfaces clean and dry.
7. Follow the manufacturer's temperature and usage recommendations.
8. Consult a healthcare professional if you have an existing medical condition.

Essential Sauna Accessories for a Better Experience

Creating a comfortable sauna environment involves more than choosing the right sauna. Suitable accessories can help users monitor their surroundings, organise their sessions and maintain their equipment.

Here are some products from Innie & Outie worth exploring.

1. Wooden Sauna Backrest

Designed to provide additional back support while sitting on a sauna bench.

2. Handmade Wool Sauna Hat

A traditional sauna accessory for users who prefer additional head coverage during their sessions.

3. Wooden Sauna Thermometer and Hygrometer

Monitoring temperature and humidity helps users understand their sauna environment and follow recommended operating conditions.

4. Sauna Sand Timer – 15 Minute

A simple accessory for keeping track of sauna session duration rather than relying on guesswork.

5. Wooden Sauna Bucket and Ladle Set

A traditional sauna accessory for managing water in compatible sauna environments. Always follow the sauna manufacturer's instructions.

6. Sauna Essential Oils Set – Eucalyptus, Pine and Birch

For users who enjoy aromatic sauna experiences. Only use products specifically suitable for sauna environments and follow dilution and safety instructions.

7. Double Wall Stainless Sauna Water Bottle

A practical accessory for keeping drinking water available as part of your hydration routine.

Explore the Innie & Outie product collection to discover sauna accessories and wellness essentials.

Frequently Asked Questions

1. Is using a sauna every day safe?

Safety depends on individual health, temperature and session duration. People with underlying medical conditions should consult a healthcare professional.

2. How long should a sauna session last?

There is no universally safe duration for everyone. Start with shorter sessions, follow the manufacturer's guidance and leave whenever you feel uncomfortable.

3. Can sauna use cause dehydration?

Yes. Sweating during sauna use causes fluid loss, which can contribute to dehydration if fluids are not replaced.

4. Is sauna use safe for people with heart conditions?

It depends on the specific condition and its stability. People with cardiovascular conditions should seek medical advice before using a sauna.

5. Can sauna use affect male fertility?

Some research suggests that repeated high-temperature sauna exposure can temporarily affect sperm production and motility. The available evidence is limited, and the observed changes in one small study were reversible.

6. Can sauna use improve cardiovascular health?

Observational studies have associated frequent sauna bathing with lower cardiovascular mortality. However, these findings do not establish that sauna use directly prevents heart disease.

Final Thoughts

Saunas can be a valuable addition to a wellness routine, but responsible use matters.

Understanding dehydration, overheating, cardiovascular stress and other potential risks can help people make informed decisions before stepping into a sauna.

The goal should not be to spend as much time as possible in the sauna. It should be to enjoy heat exposure safely, understand your body's limits and maintain a comfortable environment.

Explore Innie & Outie's range of sauna accessories to help create a more comfortable and organised wellness space.

Medical disclaimer: This article is for educational purposes only and is not a substitute for professional medical advice, diagnosis or treatment.

Scientific References

1. Laukkanen T, Khan H, Zaccardi F, Laukkanen JA. (2015). Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events. JAMA Internal Medicine, 175(4), 542–548. https://doi.org/10.1001/jamainternmed.2014.8187
2. Garolla A, Torino M, Sartini B, et al. (2013). Seminal and molecular evidence that sauna exposure affects human spermatogenesis. Human Reproduction, 28(4), 877–885. https://doi.org/10.1093/humrep/det020
3. Hannuksela ML, Ellahham S. (2001). Benefits and risks of sauna bathing. The American Journal of Medicine, 110(2), 118–126. https://pubmed.ncbi.nlm.nih.gov/11165553/
4. American College of Obstetricians and Gynecologists. Can I use a sauna or hot tub early in pregnancy? https://www.acog.org/womens-health/experts-and-stories/ask-acog/can-i-use-a-sauna-or-hot-tub-early-in-pregnancy
5. Centers for Disease Control and Prevention. Heat-related illnesses and symptoms. https://www.cdc.gov/niosh/heat-stress/about/illnesses.html
6. Injuries related to sauna bathing. (2023). Injury. https://pubmed.ncbi.nlm.nih.gov/37211472/