An avanto is a hole cut in lake or sea ice, and in Finland it is the cold half of a sauna evening: heat up for 10–15 minutes, walk out, lower yourself into water just above 0 °C for a few seconds to a minute, and go back in. Finland's largest outdoor association says the length of the dip matters less than doing it regularly, and that a quick dip is always enough. Keep your head out of the water and covered, because Finnish winter swimmers treat headwear as the most important piece of kit.
By Fuentes, founder of Lanoviss · October 2026
Most of the guides that rank for "sauna cold plunge" are written by companies that sell plunge tubs. The Finnish version is older, simpler and more cautious, and it has a few rules worth copying, including one about your head that the tub guides skip.
What does avanto mean?
Avanto is Finnish for an ice hole, natural or cut, from the verb avata, "to open" (Wiktionary). Swimming in one is avantouinti, and you go avantoon, "into the ice hole."
It is a big habit for a small country. As many as 150,000 Finns take regular winter dips, Finland has more than 200 registered winter swimming clubs and facilities, the first clubs date from the 1920s, and national championships have been held every year since 1989 (thisisFINLAND, 2017). In a survey of 642 Finnish winter swimmers by researchers Antti Lindfors and Taina Kinnunen with Suomen Latu, about half said they swim from a sauna (Latu & Polku, 2022, in Finnish).
How long should you stay in the water?
Seconds at first, about a minute once you are used to it. Suomen Latu tells newcomers that a simple dip is always enough and that regularity matters more than duration (Suomen Latu, in Finnish). The UK Met Office explains why the first minute and a half is the risky part: water below 15 °C triggers cold water shock, a gasp and a spike in breathing and heart rate whose initial effects typically last about 90 seconds (Met Office).
Experienced swimmers don't stay long either. In a 2021 study of eight Danish winter-swimming men, the average immersion lasted 1.4 minutes, and their whole week added up to about 11 minutes in cold water and 57 minutes in the sauna (Søberg et al., 2021). Those numbers describe what eight men happened to do, not a dose anyone tested, but they are a useful reality check on minute-counting.
| What eight experienced winter swimmers did | Average |
|---|---|
| Swims per week | 2.6 |
| Dips per visit | 2.6 |
| Minutes per dip | 1.4 |
| Sauna rounds per visit | 2 |
| Minutes per sauna round | 11.1 |
| Cold water per week | 11 minutes |
| Sauna heat per week | 57 minutes |
Why keep your head dry and covered in an avanto?
Because your head is the part of you that stays out of the water, and it has to stay warm. Suomen Latu's magazine calls headwear the most important piece of gear for heat balance, ahead of gloves and neoprene booties (Latu & Polku), and at Finland's national winter swimming championships headwear is compulsory, from swim caps to woolly hats (thisisFINLAND). Wet hair makes it worse, which we cover in should you wet your hair before a sauna?
Can you wear your sauna hat to the ice? At an outdoor avanto, yes, as long as your head stays above the waterline; Finnish felt makers sell their sauna hats for warmth in cold water and hot tubs as well as for heat (Finnish Felt Factory). In a shared indoor plunge pool, take it off, as our sauna etiquette guide says. Our own Merino Wool Sauna Hat is 3 mm one-piece wool felt; after an evening of rounds, dry it flat for a full day.
[DATO PROPIO PENDIENTE: wear a Lanoviss hat for three avanto rounds at −5 °C or colder; record whether the damp felt stiffens with frost and how many hours it takes to dry flat indoors.]
Is sauna plus ice water good for you?
Possibly, but the evidence is thinner than the marketing. A 2022 review of 104 studies in the International Journal of Circumpolar Health found some beneficial effects of voluntary cold-water immersion, but most studies were small, often single-sex, and could not show whether winter swimmers were healthier to begin with; the authors call it a continuing subject of debate (Espeland et al., 2022).
The individual studies are modest. A Finnish study that followed winter swimmers through one four-month season found less tension and fatigue and more vigour than in a control group, in a non-randomised comparison (Huttunen et al., 2004). The 2021 Danish study found that winter swimmers produced more heat when cooled than controls did, even though their brown fat activated about the same (Søberg et al., 2021). And a 2017 review led by cold-water physiologist Mike Tipton notes that cold water can be threat or treatment depending on circumstance, with some claimed benefits still resting on anecdote (Tipton et al., 2017).
Who should skip the ice hole?
Anyone with a heart condition, a respiratory infection or a fever, according to the Finnish Sauna Society (YIT), and anyone with heart complaints or high blood pressure, who should avoid cold water straight after the hot room (thisisFINLAND). If that might be you, ask your doctor before you try it.
Everyone else should respect the switch. Lindfors warns that alternating hot and cold puts a particular load on the body, so cool down properly before going from hot löyly to cold water (Latu & Polku). Go with someone and enter slowly rather than jumping (Met Office), breathe out long and slow through the first gasp, as Lindfors advises, and watch your footing: the same Finnish article notes that winter swimmers get hurt on slippery paths more often than in the hole itself.
Ice hole, plunge tub or cold shower: which works?
Any of them, if the water is cold enough to make you gasp. Lindfors points out that a plain cold shower is still a valid, controlled way to get cold exposure, even if it feels harsher than lowering yourself into water (Latu & Polku).
| Avanto (ice hole) | Plunge tub or pool | Cold shower | |
|---|---|---|---|
| Water temperature | Just above 0 °C under the ice | Whatever it is set to; cold shock starts below 15 °C | Whatever your tap gives |
| Your head | Above water, covered | Above water; hat off in shared pools | Hard to keep dry |
| Gear | Hat, gloves, booties; a swimsuit at public sites | Swimsuit | None |
| Best for | The full Finnish routine | Spas and home saunas | Trying it at home first |
How many rounds, and should you finish hot or cold?
Two or three rounds is typical. In Finland most people have at least two sessions in the hot room (thisisFINLAND), and the Danish winter swimmers averaged two sauna rounds and 2.6 dips per visit. For timing inside the hot room, see how long to stay in a sauna.
As for finishing, we found no study that compares ending on cold with ending on heat. What the safety guidance agrees on is the end of the evening: once you are out of the water for the last time, get into dry clothes and have a warm drink (Met Office).
Frequently asked questions
How cold is the water in an avanto?
Just above 0 °C. Water under lake or sea ice stays just above freezing even when the air is −20 °C, which is why dips are counted in seconds.
How long should a beginner stay in a cold plunge after the sauna?
A few seconds is enough. Suomen Latu says a simple dip always counts, and the gasp and racing pulse of cold water shock typically take about 90 seconds to settle.
Should you wear a hat when ice swimming?
Yes. Suomen Latu's magazine calls headwear the most important gear for staying warm, and Finland's national winter swimming championships require it.
Can you wear a felt sauna hat into a cold plunge?
Outdoors, yes, if your head stays above the water. In a shared plunge pool, take it off first, and dry the felt flat for a full day after use.
Should you end a sauna session on cold or hot?
No study we found has compared the two. Whichever you choose, finish the evening by getting into dry clothes and having a warm drink.
Is a sauna and cold plunge safe with high blood pressure?
Finnish guidance says people with heart complaints or high blood pressure should avoid cold water straight after the hot room. Ask your doctor before trying it.
This article reports published guidance and studies; it is not medical advice. Lanoviss makes no health claims for cold water, sauna use or our hats.
Fuentes is the founder of Lanoviss, which makes one product: a seamless sauna hat pressed from a single piece of 3 mm wool felt and shipped from Vancouver, British Columbia. Every external claim on this page links to its source, and the Finnish-language sources are translated by us. More about who makes it and why.
Related reading: your first sauna, step by step · how often should you sauna? · sauna etiquette for your first time