Evidence review
How long should you stay in a sauna?
Forty-five minutes of infrared moved core temperature by 0.0°C. Thirty minutes of hot sauna moved it more. What the duration research shows—and how to use a timer well.
Guided sessions for every kind of heat.
A sauna clock for your phone and your wrist. Every session is drawn on its face, from the first minute of heat to the last of the cool-down.
Every guided session free · No account required
9:41
Continuous Sauna · 1 / 2
05:16
Fifteen minutes in. Five minutes remain, but there is no need to stay for a research marker.
05:16
Sauna
Traditional saunaInfraredSteam roomHot bathRed light
Pick a shape, not a number.
Every session is a sequence of phases — heat, rest, cool-down — and each one shows its shape on its own small clock. You can see how long it runs and how many rounds it has before you read a word.
Browse every session9:41
Sessions
Beginner Sauna10 min · Wellness
›Exercise + Sauna 1520 min · Recovery
›Frequent Sauna 2025 min · Habit
›+
Build your own
ProNumbers you can’t fail at.
The days you went, lit on a month. Every figure is measured against your own history, never a target and never other people. When an input is missing, the track goes dashed instead of pretending the score was complete.
How the timer records a session9:41
History
October 2026
Active weeks
31of 52Average heat load
47of 100Sessions with all four inputs
9of 24Every marker names its own limits.
Where a duration is backed by a specific study, Heatspace shows that study’s design, population, and protocol alongside it — including the trials that found nothing. Where the evidence rests on something the app cannot measure, it shows no marker at all, and says why.
How we read the research9:41
The research
Association only
52% lower
rate of sudden cardiac death
Over 20 years in 2,315 Finnish men who usually stayed 19+ min, next to men who stayed under 11.
Observed, not proven to be caused by the sauna. Sessions of 11–19 min showed no clear difference.
Full detailA marker means you matched a duration used in a study — not that you got the result.
The rest of it.
Lock Screen and Dynamic Island
Time left, the current phase, and temperature — without unlocking anything.
Apple Watch
Run the whole session from your wrist. It saves once, even if your phone was running too.
Apple Health
Finished sessions save as workouts, with duplicate protection.
Voice cues
Spoken prompts at the moments that matter, in a minimal or fuller mode. Turn them off and nothing speaks.
Your own sessions
Build a phase sequence with your own durations, watch its shape on the clock as you go, and save it alongside the rest.
Heat Load
One score out of 100 from duration, temperature, heart response, and how hard it felt.
Nothing here needs an account.
- Sign in only if you want Pro to follow you onto another device. The sessions, the timer, and your history work without it.
- No cross-app tracking and no advertising identifiers, in the app or on this site.
- The app asks for no location access at all.
- Apple handles the payment. Heatspace never sees your card.
Questions people ask first.
Do I need a real sauna?
No. Heatspace runs traditional sauna, infrared, steam room, hot bath, and red light sessions, each with its own temperature range, pacing, and safety notes.
Can I leave my phone outside the room?
Yes. The Apple Watch app runs the whole session from your wrist, and a session that ran on both saves to Apple Health only once.
What do I get for free?
Every guided session in the library, the timer, your history, and Apple Health saving. Pro adds sessions you build yourself, the Heat Plan and its reminders, and trends and recovery insights.
How does it decide what counts as evidence?
Only a specific study can put a duration marker on a session, and the marker carries that study's design, population, and protocol — including trials that found nothing. Cool-downs and split rounds are never counted toward it.
Is Heatspace medical advice?
No. It is general wellness guidance. It never asks you to stay in the heat to reach a marker, and it tells you to leave if you feel unwell.
Research you can actually use.
Evidence review
How often should you use a sauna?
The 4–7 sessions per week figure comes from one group of Finnish men. Here is what those studies measured, what a randomized trial found, and how to pick a rhythm.
Evidence review
Steam room vs sauna: what the research actually shows.
A research-led comparison of steam rooms and dry saunas, including humidity, heat strain, practical protocols, safety, and the limits of current evidence.
Find your space in the heat.
Guided sessions across five practices, on iPhone and Apple Watch.
Every guided session freePro $4.99/month$29.99/year$49.99 lifetime (CAD)
Heatspace is general wellness guidance, not medical advice. It never asks you to stay in the heat to reach a marker. Follow your facility’s rules, and leave immediately if you feel dizzy, faint, or unwell.
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