“A sauna session is as good as a workout.”

The research found this

Heat makes the heart work harder. In 50 adults using saunas with water thrown on the stones, heart rate climbed from 79 to 121 beats a minute over a 10-minute bout.1Source 1 · Clinical trialTemperature and humidity independently influence thermoregulatory responses during Finnish sauna bathingLaatikainen-Raussi I, Mikkola T, Ihalainen JK, et al.. Temperature, 2026.Read the paper ↗PubMed ↗ Another study put 19 adults in a 93°C sauna for 25 minutes. Their heart rate and blood pressure rose steadily, and the authors matched the strain on the heart to pedaling a bike at 60 to 100 watts.2Source 2 · Clinical trialThe blood pressure and heart rate during sauna bath correspond to cardiac responses during submaximal dynamic exerciseKetelhut S, Ketelhut R. Complementary Therapies in Medicine, 2019.Read the paper ↗PubMed ↗

The extra pumping comes from a faster beat. In a head-to-head test in 20 young adults, three 10-minute bouts in a traditional sauna raised the heart's output from 5.0 to 7.3 liters of blood a minute. The amount pumped with each beat rose only from 70.2 to 71.2 milliliters.3Source 3 · Crossover trialComparison of thermoregulatory, cardiovascular, and immune responses to different passive heat therapy modalitiesAtencio JK, Reed EL, Wiedenfeld Needham K, et al.. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2025.Read the paper ↗PubMed ↗ In long experiments that heat people at rest, blood flow to the skin can take more than half of the heart's output as the body sheds heat.4Source 4 · ReviewHuman Cardiovascular Responses to Passive Heat StressCrandall CG, Wilson TE. Comprehensive Physiology, 2015.Read the paper ↗PubMed ↗

One randomized trial compared the two directly. It used a crossover design, so each of the 10 healthy women tried every condition on separate days: 45 minutes in an infrared sauna, 45 minutes of cycling and a day of rest for comparison. The sauna raised ear temperature more than cycling did, and breathing sped up more on the bike.5Source 5 · Crossover trialInfrared sauna as exercise-mimetic? Physiological responses to infrared sauna vs exercise in healthy women: A randomized controlled crossover trialHussain JN, Cohen MM, Mantri N, et al.. Complementary Therapies in Medicine, 2022.Read the paper ↗PubMed ↗ Neither session changed blood pressure or artery stiffness compared with the other conditions. The authors described the sauna's effects as the body regulating its temperature.

Over weeks, exercise did most of the work in the one trial that tested both. During eight weeks of supervised training in Jyväskylä, exercise raised estimated fitness by 6.2 mL/kg/min compared with no training. Fifteen minutes of sauna after each session added another 2.7.6Source 6 · Randomized trialEffects of regular sauna bathing in conjunction with exercise on cardiovascular function: a multi-arm, randomized controlled trialLee E, Kolunsarka I, Kostensalo J, et al.. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2022.Read the paper ↗PubMed ↗ The Kuopio men who were both fit and frequent bathers did best. High measured fitness went with a 49% lower hazard of cardiovascular death, and frequent sauna use with a 26% lower one.7Source 7 · Cohort studyJoint associations of sauna bathing and cardiorespiratory fitness on cardiovascular and all-cause mortality risk: a long-term prospective cohort studyKunutsor SK, Khan H, Laukkanen T, et al.. Annals of Medicine, 2018.Read the paper ↗PubMed ↗