A closer look at heart health.
Long-term observations and controlled trials ask different questions. Both deserve a careful reading.
Some of the most discussed sauna research concerns cardiovascular health. The key is knowing what kind of study produced a finding. An association over decades is not the same as a treatment effect in a controlled trial.
A long view from Finland.
2,315 men followed for a median of 20.7 years
A Finnish cohort study reported an association between more frequent sauna bathing and lower risks of fatal cardiovascular events and all-cause mortality. Participants were middle-aged men, and the sauna practice was traditional Finnish bathing.
Observational research cannot establish that sauna caused the difference. Other lifestyle factors may contribute. This was not a study of Renew or an infrared cabin. Read the study ↗What happens in a controlled trial?
Exercise, with and without sauna
A 2022 randomized trial included 47 sedentary adults with at least one cardiovascular risk factor. Over eight weeks, exercise followed by 15 minutes of sauna improved cardiorespiratory fitness, systolic blood pressure, and total cholesterol more than exercise alone.
A small trial of an exercise-plus-sauna program—not proof that Renew prevents disease or that sauna replaces exercise or treatment. Read the trial ↗Different outcomes can tell different stories.
A separate 2025 analysis involving 38 sedentary adults with cardiovascular risk factors found no statistically significant between-group differences in heart-rate variability after eight weeks of exercise with or without sauna. A positive result for one measure does not mean every measure improves. Read the HRV study ↗
Curiosity, with perspective.
This field is worth following. It is also worth describing accurately. We can value a sauna ritual while being clear that it is not a cardiovascular treatment, and that population-level findings cannot predict your personal outcome.
These studies did not test Renew. If you have cardiovascular disease, unstable blood pressure, or take medication affecting circulation or heat tolerance, discuss sauna use with your clinician before starting.
