The Infusion

An infusion is a small act with a large effect. You ladle water over hot stones, the room fills with steam, and the heat that was bearable a moment before wraps close around you and begins to ask something of the body. Aufguss is the German word for the practice, and it means exactly that. Infusion. On a Saturday morning in July, Andy and I paid fifteen pounds each for ninety minutes of it, at the nine o'clock session of a small wood-fired sauna on the bank of the River Avon at Warleigh Weir, a few miles out of Bath. You reach it on foot along the canal towpath, by bus from the centre, or by car left on the verge. It is an off-grid lock-up at a public river-access point: no toilets, a coffee machine, ice creams and cold drinks for sale, room inside for about twelve. Below it the river runs cold and green and does not stop.

That morning there were only a handful of us. Two women catching up; a couple with a friend, of whom only the friend had done it before; and Ben, our guide that day. The form is a löyly, and the people on the higher benches set the pace for those below. You sit in the heat as long as you can hold it, walk the few steps down to the river for a dip, and climb back to do it again. The infusion itself runs about ten minutes. There is music. Ben talks you through it, guiding your breathing and building the heat, laying scents over the coals as he goes: Palo Santo first and ylang-ylang later, each with more water and more steam. In the Netherlands and Germany, he said, these run as performances for hundreds of people, some lasting hours. Ours was ten minutes, and it was plenty. I came out of the first round not quite knowing where the ten minutes had gone, which is the kind of thing I distrust in other people's wellness writing and will not pretend to explain here. The nearest comparison I have is breathwork, the therapeutic kind, or a meditation that went further than the ones I usually abandon, and I make it as someone ordinarily impatient with both. It will not be for everyone, and I would not sell it as though it were. Ten minutes is no time at all, and it left me quieter than it found me, which is about as much as I am prepared to claim for it.

The whole ritual is to move from the heat to the cold and back again, and the thing I want to sit with, for a player, is what that movement actually does.

I came to this the way I come to most things, through the body first and the theory afterwards. I play padel, I teach movement, and I have spent this year arguing in these pages that strength is the quiet foundation the game is built on, not the repair you reach for once the game has hurt you. So when a ritual arrives wrapped in large promises, that cold water will remake your recovery and heat will add years to your life, my instinct is neither to believe it nor to dismiss it, but to ask the body what is real. The honest answer, for the hot-and-cold ritual, comes in three parts: some of it is very real, one part of it works against the strength you are trying to build, and a good deal of what is sold with it is not true at all. Let me take them in the order the morning took them.

Heat is the older half of the ritual and the better evidenced. The strongest thing we can say comes from a long study of Finnish men, followed for two decades, in which those who used a sauna four to seven times a week had around half the risk of dying from heart disease, and markedly lower all-cause mortality, than those who went once. That is careful work. It is also observational: it can show that the two things travel together but cannot prove one causes the other, and it comes almost entirely from one country where the sauna is near-universal and the people who use it most are also, on the whole, the people who move most. The heart evidence is genuinely encouraging and genuinely unfinished, and the researchers themselves say so.

For a player, the more direct interest is heat acclimation. Sit in heat regularly and the body adapts, partly by expanding the volume of your blood plasma, which is part of why trained people move a little more easily in the heat afterwards. The study people reach for here followed six distance runners who sat in a sauna after training for three weeks and improved their endurance, their plasma volume rising by around seven per cent. Six runners is not a padel squad, and endurance running is not the stop-start, sideways, repeated-sprint sport you and I play, so I would not carry that number onto the court as a promise. What it points to is narrower and useful: if a tournament is coming in real heat, some weeks of sitting in heat beforehand is a reasonable way to arrive better prepared. The one firm rule inside all of this is about timing. Heat before you play is a way to turn up dehydrated, and dehydration is the thing that will actually cost you a match, so the sauna belongs after the padel and never before it, with water in your hand.

The infusion is more than atmosphere. The steam blocks the way your sweat cools you, and moving the air strips away the thin still layer against your skin, so the same room reads as much hotter even when the air is not. You are made to feel the heat more completely. It is often said that this moving, humid heat puts a measurably greater strain on the heart than dry heat does, and it may, but I have not found that claim properly pinned down in the evidence, so I will leave it as plausible and not established. What the infusion certainly is, beyond the physics, is shared and deliberate: a small room of strangers following one slow thing together, and the value of that is not only in your blood.

Then you leave the heat and get into the river, and the body's response is immediate and not gentle. Cold water triggers what physiologists call the cold-shock response: an involuntary gasp, fast shallow breathing, a heart rate that can climb from around ninety to over a hundred and fifty beats in the first minute, and a surge in blood pressure. This is the part of the ritual I most want you to respect. That first gasp, taken in open moving water, is how people drown, and the pressure surge is real work asked of the heart in a few seconds. It settles. Entering slowly and taking control of your first breaths is the whole of the technique, and the response softens as you repeat it across a season. But it is not nothing, and it is not to be rushed into for a photograph.

Here the evidence turned out to be more interesting than I expected. The claim I trusted least going in was the recovery claim. The one I trusted more by the end I had barely heard of. Researchers in Bangor recently tested what happens when you replace the ordinary air-rest between sauna rounds with a cold-water dip, and found it lowered the body's thermal and cardiovascular strain and made the second round of heat more tolerable. Core temperature at the end of the second sitting was lower with the cold dip than without it, and so was heart rate, and the people in the study simply felt better able to go back in. Read that against a padel weekend and it reframes the plunge entirely. Its clearest job here is temperature. The cold manages your own heat, so the sauna becomes safer to go back into and the whole cycle becomes something the body can keep doing, and recovery, if it comes, comes second. For an outdoor sauna with a river underneath it, that is the cleanest benefit on offer, and it is the one I would trust first.

The recovery claim is softer, and it needs saying carefully because it is the one everybody repeats. Cold water after hard exercise does seem to reduce next-day soreness compared with simply resting, and it does seem to leave people feeling more recovered. Both of those are documented. But the studies that show it are rated, by the people who gathered them, as low quality and high risk of bias, they were mostly done on runners and team-sport players rather than anyone holding a racket, and what they show is softer than the marketing. Cold will likely help you feel less sore and more recovered into your next match. It will not reliably restore the actual power in your legs for that match; the evidence for real strength and power coming back faster is thin and contested. And none of it was tested on padel players, so when I say it should transfer to a tournament weekend I am making a reasonable inference from a shared kind of load, not reporting a result. That distinction is the difference between a column you can trust and one you cannot.

The alternation, the going hot to cold to hot that gives the ritual its shape, deserves the same honesty. Contrast bathing beats doing nothing for soreness. What it does not do, on the evidence, is beat a plain cold plunge; there is little sign that the alternation itself adds a benefit over cold alone. So I would not call contrast a superior protocol. It is at least as good as resting; its real gift is arguably in how it feels and how it manages your temperature, and the pleasure of it is not a small thing to a body you want to keep bringing back to sport.

Now the part that matters most, and the reason this is a padel column and not a wellness one. There is a day the cold works directly against you, and it is the day you have just trained your strength. When you lift, the small inflammation that follows is not damage to be washed away. It is the signal that drives the muscle to adapt, to grow and to get stronger, and cold water damps exactly that signal down. In a twelve-week study, men who plunged in cold water after their lower-body strength sessions built less muscle than men who recovered actively, because the cold had quietened the very process that strength training exists to provoke. Later reviews have found the same for strength and power, and it has held up as more people have looked. The thing cold does so well, calming the body after effort, is the thing that quietly cancels the work you did to build the body underneath your game.

This is where the ritual meets the argument I have been making all year. Strength is the foundation. If you are in a training block, deliberately building the base that lets your knees bend to every low ball and your shoulder carry every bandeja, then cold water in the hours after your strength sessions works against you. You are cooling the adaptation off before it has happened, quietly undoing the very session you turned up to do. The answer to this is not a ban, it is a matter of timing. Keep the cold away from the sessions whose whole purpose is to change you, and it costs you nothing there. Bring it out on the days when the purpose is not to adapt but to compete again soon: the tournament weekend, three matches deep, when what you need is to feel less sore and more able for the next one and there is no adaptation to protect that day. The more clearly you separate the day you are building the body from the day you are only asking it to perform, the more useful the cold becomes and the less it takes from you. Same water. Opposite verdict. It depends entirely on what you asked of yourself that morning.

A good ritual attracts bad claims, and it is worth naming them plainly, because a column that repeats them is not looking after you. A player hears most of them in the same key: the plunge sold as the edge that will sharpen the next match, the sweat sold as the thing that undoes a heavy weekend. The edge is mostly not there. Sweating does not detox you; your liver and kidneys do that, and your sweat is almost entirely water. A short plunge does not flood your brain with dopamine for hours and rewire your motivation; the large chemical numbers people quote came from an hour spent immersed to the neck, not from a minute in a river, and the lasting-mood version is an extrapolation, not a finding. Heat is not a meaningful way to burn calories or lose weight, and neither cold nor heat is the anti-ageing cure the louder end of the industry sells. And the nature around it, the green water and the trees and the open sky, which genuinely does seem to be good for how people feel, is measured in studies that cannot cleanly separate the water from the cold, the exercise, the company and the ritual all arriving together. So I will give you the nature honestly: it felt like it mattered, and there is real if tangled evidence that it does, and I will not dress a feeling up as a mechanism.

The plain safety version, because the ritual joins two things your body finds hard and does it in seconds. Heat leaves you flushed, your vessels open and your blood pressure low. The cold plunge then slams the opposite onto that in an instant: vessels clamping shut, pressure surging by thirty to fifty points, the heart swinging hard from one state to the other. For most healthy people that swing is tolerable and even welcome. For some it is not. If you have unstable angina, if you have had a heart attack in the last few months, or if you have a tight narrowing of the heart's main valve, this hot-to-cold sequence is exactly the kind of demand those conditions tolerate worst, and it is not for you without a doctor's clearance. The same holds in pregnancy and in acute illness: ask first. Do not drink alcohol before any of it; alcohol with heat is the single most preventable danger in the whole practice. Get into the cold slowly and never head-first, because of that first gasp. And know that your temperature can keep falling after you climb out, as the cold blood in your limbs returns to your centre, so re-warm gently and do not stand around wet in the wind congratulating yourself. None of this is meant to frighten you off. It is meant to keep the ritual something you can do for years, which is the only timescale on which any of it matters.

We stayed the ninety minutes and did the cycle three times: heat, river, heat, river, heat, river, and a long slow re-warm at the end with the Avon going past. I have thought since about why it felt larger than the sum of its evidence, and I think it is because the ritual gives the nervous system a single clear instruction after a week of small unfinished ones. You cannot half-attend to cold water. It takes all of you, briefly, and hands you back slightly reset. The more honestly you use it, the more it gives: the cold for the tournament days and the temperature it manages, the heat after play and never before, the strength left uncooled on the days you build it. I would not call any of it the recipe for a padel body. The recipe is the training. This is the ritual you keep around the training, on the days it serves you, on a riverbank, for as long as the body will still climb the bank and go back in.