Three situations where the sources say no, and four nobody has studied. What the research actually says before you book a sauna or an ice swim.
Between 1990 and 2002, fewer than two people per 100,000 inhabitants died in a sauna in
Finland each year, and half of them had been drinking. That figure is the whole subject in
one line. The sauna and the ice hole are not dangerous, but a few things around them are, and
those few things are known fairly precisely.
Three situations get a flat no from the sources: alcohol, fever and going alone. Four more,
asked just as often, have no research behind them at all. Here is each one, and what the
Alcohol. A peer-reviewed review says it outright: drinking during a
sauna raises the risk of low blood pressure, arrhythmia and sudden death, and should be
avoided. Suomen Latu says the same about the water.
Illness, especially a fever. Skip both. The named risk is not
discomfort. It is that exertion may increase the danger of a complication such as viral
Going in alone. Suomen Latu’s safety list opens with it, and the
reason is a reflex you cannot override by willpower during the first minute.
Blood-pressure medication is a caution, not a ban, and the pressure drop
comes after the sauna rather than during it.
Periods, a heavy meal, poor sleep, a hard workout just before. Not one
source we opened addresses any of them. That is not the same as safe.
Drinking during a sauna raises the risk of low blood pressure, arrhythmia and sudden death,
and should be avoided. That is the conclusion of a peer-reviewed review of sauna benefits and
risks, and it is unusually direct. Suomen Latu is just as short about the water: do not swim
while ill or under the influence of alcohol, and never alone.
Ten healthy men were measured sober and after heavy drinking. The sauna alone left systolic
blood pressure at baseline. The sauna combined with heavy drinking dropped it from 136 to
113 mmHg. Ventricular extra beats did not increase in either condition, and they were the
only arrhythmia this experiment counted. The authors’ own sentence is about blood
pressure, not collapse. Nobody fainted in this experiment, because fainting was not measured.
Death in a sauna is rare. In Finnish forensic data from 1990 to 2002 it ran to fewer than two
cases per 100,000 inhabitants per year, and half of those cases were under the influence of
alcohol. The researchers’ own prevention advice has two halves, and the second one gets
forgotten: less alcohol, and do not leave an intoxicated bather alone.
Drownings have their own Finnish dataset: 1,697 accidental drownings of people aged 15 and
over between 2000 and 2009, all forensically tested. Alcohol-positive cases, defined there as
a blood alcohol concentration of at least 0.5 per mille, made up 61.8 per cent of
non-boating drownings and 65.0 per cent of boating ones. The figure says how many drowning
victims had alcohol in their blood. It does not say how many drinkers drown.
And a hangover? The useful question is not how you feel but whether there is still alcohol in
your blood. If there is, everything above applies and the hangover changes none of it. If
there is not, we found no study at all on hangovers combined with a sauna or an ice hole, and
The beer straight after the steam is a smaller question with a real answer. In a rehydration
experiment where the fluid loss had been induced by exercise, a 4 per cent drink slowed the