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Heat acclimation
Hot water immersion
Heat shock proteins
Sleep and heat

SHORT ANSWER

Heat exposure can lower blood pressure during recovery, and repeated heat may modestly improve resting pressure in some groups. Long-term trials are still small and mixed, and heat has not been shown to replace blood-pressure medication.

What we know

Meaningful heat exposure increases skin blood flow, usually raises heart rate and cardiac output, and can lower vascular resistance and blood pressure during recovery.
Sources 42, 45

What is emerging

Repeated whole-body heat may modestly improve resting or ambulatory blood pressure in selected groups, especially when the heat dose is sufficient.
Sources 6, 7, 53, 63, 66–68

What we don't know

Randomized trials remain small and varied, so the long-term effect on blood pressure and artery measures depends on which studies are included.
From the book only

Heat Health's perspective

Dr. Soffer finds the blood-pressure signal compelling, but cares far more about a patient's standardized home trend than the lowest number someone can produce after sweating. He sees heat as a possible adjunct to blood-pressure control, alongside better diet and exercise.
Dr. Soffer's Clinical Perspective · Chapter 6

Safety first (from the book)

If you have diagnosed hypertension, very low or highly variable pressure, heart or kidney disease, or take blood-pressure-lowering medicines, discuss deliberate heat with your clinician before beginning or intensifying it. Do not use a sauna or hot bath as an acute rescue for a dangerously high reading.
Sources 20, 62

sources

6. Brunt VE, et al. Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans. J Physiol. 2016. DOI
7. Lee E, et al. Effects of regular sauna bathing in conjunction with exercise on cardiovascular function: a multi-arm, randomized controlled trial. Am J Physiol Regul Integr Comp Physiol. 2022. DOI
17 (also cited as 45). Laukkanen T, et al. Acute effects of sauna bathing on cardiovascular function. J Hum Hypertens. 2018. DOI
20. CDC and NIOSH. Heat-related illnesses. Updated February 6, 2024. Link
42. Crandall CG, Wilson TE. Human cardiovascular responses to passive heat stress. Compr Physiol. 2015. DOI
6. Brunt VE, et al. Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans. J Physiol. 2016. DOI
7. Lee E, et al. Effects of regular sauna bathing in conjunction with exercise on cardiovascular function: a multi-arm, randomized controlled trial. Am J Physiol Regul Integr Comp Physiol. 2022. DOI
17 (also cited as 45). Laukkanen T, et al. Acute effects of sauna bathing on cardiovascular function. J Hum Hypertens. 2018. DOI
20. CDC and NIOSH. Heat-related illnesses. Updated February 6, 2024. Link
42. Crandall CG, Wilson TE. Human cardiovascular responses to passive heat stress. Compr Physiol. 2015. DOI
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From the book: Chapter 6, “Heat and Blood Pressure”
This version answers from the manuscript. Responses are AI-generated and are not individually reviewed by an advisor.
For more detail, download Heat Health or purchase the paperback.
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This answer was generated by AI from the Heat Health Book and Heat Health Advisors and its reference list. It is general education, not medical advice.

Urgent question

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Personal medical question

Ask Heat Health shares general educational information from the Heat Health book. It cannot give personal medical advice, diagnose, or tell you whether heat is safe for you. Please talk to your doctor or another qualified clinician about your situation.

Not covered in the book

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