The 10-minute heat break: what to actually do with it
From the start of the 2026 season the ATP has a heat rule, which means that for the first time a man on tour can be handed 10 minutes off court in the middle of a match and told to sort himself out. The women have had this since 1992. In all that time I have not found a single piece of writing that says what to do with the time.
So the rule is settled and the protocol is not. That gap is where matches are lost, because 10 minutes is enough to change the third set and it is also easily enough time to do nothing useful at all.
What the rule actually says
The ATP policy runs on Wet Bulb Globe Temperature, which combines air temperature, humidity, wind and radiant heat into one number, and is a far better measure of what the court is doing to you than the figure on your phone.
When WBGT reaches 30.1 degrees or higher during the first two sets of a best-of-three singles match, either player may request a 10-minute cooling break after the second set, and it applies to both. Inside the break you may hydrate, change clothing, shower, use cooling measures and receive coaching, under the supervision of ATP medical staff. If WBGT passes 32.2 degrees, play is suspended.
The WTA has run a comparable rule since 1992. The Grand Slams sit outside the ATP policy and operate their own: the US Open, Roland Garros and Wimbledon use WBGT-based rules, while the Australian Open runs a Heat Stress Scale from 1 to 5, with 10-minute breaks arriving at level 4 and play on outdoor courts halted at level 5.
The break is requested, not automatic. If you are the player who is struggling and you wait for someone else to ask, you may not get it.
What 10 minutes can and cannot do
Be clear about the size of the job. You are not going to reverse core temperature accumulated over 2 sets in 10 minutes, and you are not going to replace a fluid deficit of a litre and a half. Absorption does not work that fast.
What you can do is take the edge off thermal strain, put back some of what you have lost, and arrive at the third set with less of a deficit than you would otherwise have carried into it. That is worth having. It is not a reset.
The mistake I see is treating the break as a recovery session and doing everything slowly and thoroughly, so that the shower takes 4 minutes and the drinking gets 1. Order matters more than effort here.
The order I would use
First 60 seconds, drink. Cold fluid with sodium, and start immediately, because whatever you drink in the first minute has the longest time to leave the stomach before you are back on court. Do not sip politely. Do not drain a litre either: gastric emptying has a ceiling and the fluid that is still in your stomach at minute 10 is fluid you have to run with.
Same 60 seconds, get ice on skin. Neck, face, head, inside of the forearms. They are accessible, richly supplied with blood, and you can reach them while doing something else; no controlled trial shows them beating the torso. How much cooling you get depends mostly on how much surface you cover and for how long. Ice towels held against the neck and face while you drink is two jobs in one minute.
Minutes 2 to 5, cool properly. If ice water is available, immerse hands and forearms in it. The forearm and palm carry a dense arteriovenous network and immersing them moves heat out faster than draping a towel over your shoulders looks like it should. Ice slurry, if the tournament has it, is worth taking, though the evidence is more complicated than the marketing. Internal cooling works best before you start rather than in the middle, and during exercise part of the benefit is handed back, because a cooler core sweats less and you lose some evaporative cooling in exchange. Internal and external cooling both work. Which one wins depends on timing, conditions, and whether you are trying to move core temperature, skin temperature or simply how bad it feels.
Minutes 5 to 7, change and eat. Dry kit, because a wet shirt in humidity has stopped evaporating anything. And this is a feeding window as well as a cooling one, which everybody forgets. If you are 2 sets in, you have used a lot of glycogen. Take carbohydrate here, in the same form you would use on a changeover.
Minutes 7 to 9, coaching. The rule allows it. Use it late rather than early, because a tactical conversation held while you are still overheated is a conversation you will not remember.
Last minute, stand up and move. Do not walk back on cold and stiff from sitting. A short walk and some easy movement before you leave the room.
The same block, as a printable card with the acclimatisation protocol beside it, is in the Tennis Competition Guide.
The shower question
The rule allows a shower and most players take one. Cold water over the whole body does cool you, and it also eats 3 of your 10 minutes, leaves you damp, and can trigger enough peripheral vasoconstriction that heat loss from skin actually slows for a while afterwards.
My view, which is a judgement rather than a finding: a shower that is quick and cool rather than cold pays off in dry heat and is questionable in humidity, where you will not evaporate anything afterwards anyway. If you take one, take it in the middle of the block and not at the start, so the drinking has already happened.
The work that happens before the tournament
None of the above matters as much as arriving acclimatised, and this is the part players skip because it is inconvenient.
Heat acclimatisation takes repeated exposure over roughly 10 to 14 days, with sessions of about an hour in the heat, and it produces real adaptations: plasma volume expands, sweating starts earlier and at a higher rate, and sweat sodium concentration falls. An acclimatised player doing the same work in the same conditions is under measurably less strain than they were 2 weeks earlier.
This is the single biggest lever available and it cannot be pulled during the match. If your season takes you into a hot swing, the adaptation has to be built before you fly, or in the first days on site, and not left to happen by accident during the first round.
Playing again tomorrow
A hot match costs you more than the match. You finish with a fluid deficit, depleted glycogen and a body that has spent hours working to shed heat, and then the draw asks you to do it again in under 24 hours.
Rehydration is the part most players underestimate. Replacing what you lost requires more volume than you lost, because some of it goes straight out again, and it requires sodium to hold it. Drinking plain water in volume after a hot match dilutes what is left and is the mechanism behind the worst outcomes in this whole area.
Carbohydrate goes back in early, in the hours after you come off, because glycogen resynthesis is fastest then and you have a fixed and short window before you need it again. And sleep in a cool room, because a body still shedding heat sleeps badly, and sleep is doing more for tomorrow than anything else on this list.
What I would tell a player
Ask for the break. It is requested, not granted automatically, and the player most likely to need it is the player least likely to be thinking clearly enough to ask.
Have the block rehearsed before you need it, in the same way you rehearse a return. Ten minutes is short and it disappears if you spend the first 3 deciding what to do.
And do the acclimatisation. The rule is a safety net, not a plan. It exists because players were collapsing, not because 10 minutes is a good answer to a hot afternoon.
Common questions
From the 2026 season the ATP operates a heat rule based on Wet Bulb Globe Temperature. When WBGT reaches 30.1 degrees or higher during the first two sets of a best-of-three singles match, either player may request a 10-minute cooling break after the second set, and it applies to both players. Play is suspended if WBGT passes 32.2 degrees. The WTA has had a comparable rule since 1992. The Grand Slams operate their own policies, with the Australian Open using a Heat Stress Scale from 1 to 5.
Under the ATP rule a player may hydrate, change clothing, shower, use cooling measures and receive coaching during the break, under the supervision of ATP medical staff.
Start drinking cold fluid with sodium immediately, and put ice on the neck, face, head and inner forearms while you do it, because those sites are accessible and well supplied with blood rather than because they outperform other sites in trials. If ice water is available, immersing the hands and forearms moves heat out efficiently. Ice slurry is useful and works best as pre-cooling, since during exercise part of its benefit is offset by a reduced sweat rate. Both internal and external cooling work, and how much you get depends on surface area and contact time. Leave changing kit and any coaching conversation until after the cooling and drinking have happened.
It is allowed and it does cool you, but it costs about a third of the break and can slow heat loss from the skin afterwards through peripheral vasoconstriction. If you take one, take it cool rather than cold, take it in the middle of the break rather than at the start, and consider skipping it in high humidity where you will not evaporate anything afterwards.
Roughly 10 to 14 days of repeated exposure, with sessions of about an hour in the heat. The adaptations include expanded plasma volume, sweating that begins earlier and at a higher rate, and a fall in sweat sodium concentration. This has to be built before the tournament and cannot be achieved during a match.
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Educational material, not medical advice. Heat illness is a medical emergency and should be treated as one.