cold plunge

What your heart rate does when you \"totonou\": the Japanese sauna high, on a chart

ととのう is the calm, floating state after sauna, cold water, and rest. It has a shape on a heart rate chart: a climb, a cliff, and a dip below where you started. What each part is, why it feels the way it does, and how to tell a real one from a near miss.

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Cold plunge: how long, and what temperature? The numbers, and what your heart rate says on the way out

Thirty seconds to two minutes at 15 to 18°C is the standard. What happens in the first ten seconds, why staying longer does not help, what a single-digit bath changes, and how to read the drop on your watch.

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How long in the sauna, how long in the cold plunge, how long to rest

The standard answer is 8 to 12 minutes, 1 to 2 minutes, and 5 to 10 minutes. The better answer comes from your heart rate. Both are here, with what to do on your first day.

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