The heat raises your heart rate and moves blood toward your skin. For most healthy adults that is safe, but some conditions and medicines turn it into a real risk.

Don't use the sauna if you have

  • Chest pain that comes on at rest or is getting worse (unstable angina)
  • Had a heart attack in the last few weeks
  • Severe narrowing of the aortic valve (aortic stenosis)
  • Heart failure that is not under control
  • High blood pressure that is not under control
  • A fever, or an acute infection or inflammation
  • Been drinking alcohol
  • A fentanyl skin patch: heat can release a dangerous dose

Ask your doctor first if you

  • Are pregnant, especially in the first three months: overheating is linked to birth defects, so keep your core temperature below 39 °C
  • Have a heart rhythm problem, heart valve disease or another heart condition
  • Have low blood pressure, often feel faint when standing up, or have POTS
  • Have a condition that makes you sensitive to heat, such as multiple sclerosis
  • Have a bleeding disorder, kidney disease, or another chronic illness
  • Have open wounds, hives or an inflamed skin condition

Medicines to check

Beta-blockers, nitrates, diuretics, other blood pressure medicines, stimulants (including ADHD medicines), and medicines that reduce sweating, such as some antihistamines and antidepressants. They can lower your blood pressure, change your heart rate or stop you cooling down.

Children, older adults, trying for a baby

Children and older adults heat up and dehydrate faster: keep sessions shorter and cooler, and never leave a child alone in the sauna. For men trying to conceive, regular sauna use lowers sperm count for a few months; it recovers after stopping, and cooling protection helps.

Get out straight away if you feel

Dizzy, sick, confused, a headache, chest pain, a racing or irregular heartbeat, or if you stop sweating or start shivering. Sit down somewhere cool, drink water, and get help if it does not pass.

Sources

  1. Hannuksela M., Ellahham S. Benefits and risks of sauna bathing. The American Journal of Medicine, 2001.
  2. Laukkanen J. A. et al. Cardiovascular and other health benefits of sauna bathing: a review of the evidence. Mayo Clinic Proceedings, 2018.
  3. Kukkonen-Harjula K., Kauppinen K. Health effects and risks of sauna bathing. International Journal of Circumpolar Health, 2006.
  4. American College of Obstetricians and Gynecologists. Physical activity and exercise during pregnancy and the postpartum period. Committee Opinion 804, 2020.
  5. Garolla A. et al. Seminal and molecular evidence that sauna exposure affects human spermatogenesis. Human Reproduction, 2013.

General information, not medical advice.