Heat changes how your body responds.
A closer look at passive heating: how it works, what researchers measure, and why sweating is only part of the story.
Heat creates a real physiological response. Understanding that response is more useful than treating every sauna claim as a promise. Infrared and traditional saunas deliver heat differently, and research on one setup does not automatically describe another.
Start with the heat, not the hype.
Infrared cabins use radiant energy to warm the body. Traditional sauna studies generally involve hotter air. Temperature, humidity, session length, and the people taking part all matter when interpreting a result. The word “sauna” is not a single, standardized treatment.
What the broader research says
A 2018 systematic review included 40 studies and 3,855 participants. Thirteen studies were randomized trials, and most were small. The authors described potential benefits alongside substantial differences in methods and insufficient evidence to define an optimal sauna protocol.
Hussain & Cohen, 2018 · Systematic review · Multiple sauna types. Read the review ↗Passive heat is not a workout.
Feeling hot and sweating can happen during exercise or while sitting in a sauna. That does not make the two activities interchangeable.
Heat and exercise: a direct comparison
In a randomized crossover study of 10 healthy women, researchers compared 45 minutes of infrared sauna, cycling, and rest. Core temperature rose more during infrared exposure, while breathing rate was higher during exercise. The responses overlapped in some respects but differed in others.
Small, acute study; not evidence that sauna replaces training or produces equivalent fitness gains. Read the study ↗What this means for your ritual
Think of sauna time as its own experience: an intentional place for warmth and a pause in your day. Keep exercise, sleep, nutrition, and hydration in the picture. More heat or longer sessions are not automatically better.
These studies did not test Renew. Editorial imagery is illustrative. Follow your sauna’s instructions, leave if you feel unwell, and discuss heat exposure with a qualified clinician if you have a health condition, are pregnant, or take medicines that may affect heat tolerance.
