Weekly goal
- What it is
- Weekly minutes of heat and of cold to aim for. The presets follow published routines; they're starting points, not prescriptions.
- How it is measured
- Beginner is 20 minutes of heat and 4 of cold a week, Intermediate 60 and 11, Advanced 100 and 20. Custom goes from 10 to 180 minutes of heat and 1 to 30 of cold. Heat counts sauna, hot baths and hot showers; cold counts plunges and cold showers. The Analysis tab's rings and 12-week chart measure against the goal you pick.
- How to read it
- Heat: in Finnish studies the typical sauna user went about twice a week for 14 minutes, and more frequent and longer use went with lower cardiovascular risk; a later sample found more than 45 minutes a week went with lower cardiovascular death than 15 or fewer. Intermediate rounds up the 57 minutes of heat and 11 of cold reported by a small group of experienced Danish winter swimmers; Advanced sits within the Finnish studies' most frequent group. Cold: no study ties a weekly cold total to long-term health. Beginner matches a trial of 30–90 seconds of cold at the end of a daily shower, and the cold shock response settles after about four to six short immersions.
- What it cannot tell you
- The sauna studies are observational, of habits reported once, mostly in middle-aged Finnish men; they show association, not a dose that causes benefit. Heat is counted the same whether it's an 80 °C sauna or a 40 °C bath, though no study sets an exchange rate between them. Cold water is riskiest in the first minute, when the gasp reflex peaks; very cold water can make it hard to move within about 10 minutes, and body temperature keeps falling for a while after getting out.
Sources
Every one of these ships inside the app, with the finding written out so you do not have to open the paper to know why it is there.
Laukkanen T, Khan H, Zaccardi F, Laukkanen JA. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Internal Medicine, 2015.
2,315 men; typical use 2.1 sessions a week of 14.2 minutes. Against once a week, 4–7 sessions went with lower sudden cardiac death (hazard ratio 0.37), and sessions over 19 minutes against under 11 (0.48).
doi.org/10.1001/jamainternmed.2014.8187Laukkanen T, Kunutsor SK, Khan H, et al. Sauna bathing is associated with reduced cardiovascular mortality and improves risk prediction in men and women. BMC Medicine, 2018.
1,688 men and women, median 30 minutes a week. More than 45 minutes a week against 15 or fewer: hazard ratio 0.57 for cardiovascular death.
doi.org/10.1186/s12916-018-1198-0Søberg S, Löfgren J, Philipsen FE, et al. Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men. Cell Reports Medicine, 2021.
Experienced winter swimmers reported about 57 minutes of sauna and 11 minutes of cold water (1–9 °C) a week. A description of their routine, not a tested dose.
doi.org/10.1016/j.xcrm.2021.100408Buijze GA, Sierevelt IN, van der Heijden BC, Dijkgraaf MG, Frings-Dresen MH. The effect of cold showering on health and work: a randomized controlled trial. PLoS One, 2016.
30, 60 or 90 seconds of cold at the end of a daily shower for 30 days; sickness absence fell 29%, and 79% kept it up.
doi.org/10.1371/journal.pone.0161749Tipton MJ, Mekjavic IB, Eglin CM. Permanence of the habituation of the initial responses to cold-water immersion in humans. European Journal of Applied Physiology, 2000.
Six 3-minute immersions at 15 °C over 4 days roughly halved the breathing response to cold water, and the change lasted months.
doi.org/10.1007/s004210000255Hannuksela ML, Ellahham S. Benefits and risks of sauna bathing. American Journal of Medicine, 2001.
Sauna is well tolerated by most healthy adults; unstable angina, recent heart attack and severe aortic stenosis are reasons to avoid it, and alcohol raises the risk of low blood pressure and arrhythmia.
doi.org/10.1016/S0002-9343(00)00671-9