ATP 2026 Heat Rule: Turn the 10-minute Break into Wins

The rule that turns heat into a tactic

The heat was already a storyline at the Australian summer swing. Now the ATP has made it a season-long variable that smart players can control. Beginning in 2026, the tour will use the Wet Bulb Globe Temperature, or WBGT, to decide when a match should slow down or stop. When the on-site WBGT reaches 30.1 degrees Celsius during the first two sets of a best-of-three singles match, either player can request a 10-minute cooling break after the second set. If the WBGT climbs above 32.2 degrees Celsius, play is suspended. The break is supervised by medical staff and coaching is permitted during the interval. These details are now part of the match just as surely as string tension or second-serve speed. They are also public, which means every player and coach can plan for them in advance. See the ATP summary of the 2026 Heat Rule for thresholds and permissions.

This article explains the thresholds in simple terms, shows how to script an effective 10-minute cooling break, and gives practice drills that simulate the re-start. You will leave with a checklist you can use immediately at your next heat-heavy stop, from Texas to Florida to South America, and you will know how to make the rule work for you instead of against you. For strategic context, see our breakdown of how WBGT thresholds change strategy.

WBGT in simple English

WBGT is a field measure that blends four things your body actually feels: air temperature, humidity, radiant heat from the sun, and wind. If a regular thermometer is the headline temperature, WBGT is the true feels-like for athletes on a hard court in the sun. Here is how to think about the two thresholds:

• 30.1 Celsius: the match continues, but a 10-minute post-second-set break can be requested by either player. If one player asks, both players get it.
• 32.2 Celsius: play stops until conditions drop below this level.

In practice this means the first two sets are a race not only to six games, but also to the best plan for the coming break. If conditions are borderline, you should already know exactly what you will do with those 10 minutes. Treat that interval like a micro-halftime with a script, roles, and equipment.

The 10-minute break, scripted to the minute

What follows is a practical template for juniors, college players, and pros. Tweak the specifics for body size, sweat rate, climate, and surface. The goal is simple: drop core temperature, replace fluid and sodium without overdrinking, reset breathing and decision-making, then return with one or two clear tactical priorities.

Pack list for the heat rule

• Cooling vest pre-chilled in a soft cooler
• Two large ice towels in zip bags, plus a small neck wrap
• Handheld fan or battery clip fan for the bench area
• Slushy bottle (half ice, half sports drink) and a squeeze bottle of water
• Measured electrolyte mix packets with known sodium content
• Spare socks, wristbands, light shirt, hat, and a small microfiber towel for drying hands
• Laminated “Heat Card” with your cues, patterns, and hydration targets

Roles on your team

• Player: follow the script, communicate symptoms, and keep timing in sight
• Coach: deliver the 60-second tactical brief, protect the plan, watch for drift
• Physio or parent: handle gear, ice towels, vest, timers, and traffic flow

Minute-by-minute plan

• Minutes 0 to 1: Move to shade immediately. Remove hat and wristbands, unzip top, loosen laces slightly if feet feel hot. Begin nasal inhale for four counts, long mouth exhale for six counts to downshift heart rate. Sit down only after active cooling starts.
• Minutes 1 to 3: Cooling first. Place a cold towel on the back of the neck and another across the thighs or lower back. Put on the cooling vest for two minutes. If a shower is available and you respond well to it, take a 60 to 90 second cool rinse. Keep the breathing protocol running.
• Minutes 3 to 6: Hydrate with intent, not guesswork. Aim for small, steady sips. A practical range for many tennis players is 300 to 600 milliliters across the entire break, adjusted by body size and thirst. Include sodium so you retain fluid and keep firing signals to drink. A common performance blend is 500 to 700 milligrams of sodium per liter of fluid, with 4 to 8 percent carbohydrate if you are moving into a long third set. These ranges come from long-standing sports science guidance such as the American College of Sports Medicine’s position stand on fluid replacement: ACSM fluid replacement guidance. Do not chug. If you finish the break bloated, you overdid it.
• Minutes 6 to 8: The 60-second coach brief. One or two clear items only. The coach reads from the Heat Card, not from memory. Example: “First two games, protect serve with wide slice to the ad court, plus forehand to backhand corner. On return, stand half step back on first serves, chip backhand middle and get the rally neutral.” No new mechanics. No multi-point lectures. Then a 30-second mental reset: pick a cue word for the re-start, for example “hold depth” or “first step.”
• Minutes 8 to 9: Activation. Light dynamic moves to wake up the chain: ten high-knees, ten butt kicks, eight alternating lunges with a twist, eight pogo hops. One or two air swings with your match racquet. No fatigue, just rhythm.
• Minutes 9 to 10: Final check. Dry hands, swap to fresh wristbands and shirt, secure hat, re-tie shoes. One more long exhale as you stand. Walk out with your first two-point pattern pre-selected. If you are receiving, execute your return position decision before you sit down on court.

What is allowed in the break

Under the ATP’s 2026 rule, players may cool down, change clothing, shower, hydrate, and receive coaching during the interval, all under supervision. That permission matters. Treat it like a short, focused timeout that must end exactly on time. The chair will call time at nine minutes and thirty seconds. Be ready.

Hydration and sodium targets without the guesswork

Hydration is personal, but planning is universal. Use these steps to turn theory into your numbers. For additional context from January’s conditions, review our Australian Open heat lessons.

1. Find your sweat rate. On a hot practice day that mimics match intensity, weigh yourself nude or in dry underwear right before and right after a 60-minute hit. Keep track of how much you drink. Every kilogram lost equals roughly one liter of fluid deficit. If you drank 500 milliliters and still lost 0.8 kilograms, your sweat rate is about 1.3 liters per hour. Repeat two or three times and average.

2. Set an in-break volume. You will not replace everything in 10 minutes. Use your sweat rate to set a safe sip target. For many players this lands between 300 and 600 milliliters total in the break, paired with sodium for retention. Smaller athletes or low sweaters can go toward the low end. Big frames and heavy sweaters go higher but should split intake across the minutes, not in one gulp.

3. Match sodium to the day. A simple starting point is 500 to 700 milligrams per liter of fluid during hot matches. If your hat shows salt rings or you routinely cramp late, test 700 to 1000 milligrams per liter. Place the measured packet in your bag before the match so you are not improvising during the break.

4. Carbohydrate is fuel. If you enter a long deciding set, a 4 to 8 percent carbohydrate solution helps maintain blood glucose. For most players that means 24 to 48 grams of carbohydrate across 600 milliliters of fluid. If you get stomach distress, dial down concentration and increase frequency of smaller sips.

5. Guardrails. Overdrinking plain water can dilute blood sodium in rare cases. If you feel sloshy or nauseous, you likely drank too much, too fast. If your urine is dark for hours after a hot match, you likely under-drank and need a short rehydration block later that day with a salty snack and measured fluids.

The Heat Card: coaching notes that fit in a pocket

Print a one-page card, laminate it, and keep it with your ice towels. Divide it into four boxes:

• Box 1: Opponent patterns. Two serve patterns you have seen, two rally preferences, one pressure tell.
• Box 2: Your match patterns. Two serve plus one options, one return plan on first serve, one on second serve.
• Box 3: Physical reset. Your breathing cue, heart rate downshift, activation sequence, and a reminder to change to dry socks if feet get hot.
• Box 4: Score triggers. What you do at 30-all on serve and what you do at 30-all on return. Keep it short. The goal is to remove indecision after the break.

A coach or parent can point and read. You do not need a speech when you are hot. You need the next two plays.

Tactics that play better in heat

Heat changes ball flight, footing, and physiology. You do not need to become a different player. You do need a version of your game that spends energy wisely.

• On serve: favor wide targets that open the court and shorten the point. Plan a first-ball forehand to the opponent’s weaker wing. If your toss drifts with the sun, move your stance an inch rather than fight a losing battle.
• On return: block more first serves back middle to take away angles. On second serves, step in only if you can neutralize in two shots, not five. Big swings at shoulder height late in the set are low-percentage in heat.
• In rallies: shift your rally height window. Heavy topspin is useful, but constantly lifting high in thick air is expensive. Mix in line drives through the middle third of the court to reduce court coverage and force errors.
• At net: a single strong approach per game is worth more than three half chances. Use the wider serve as your green light.
• Between points: work the legal time. Walk back to the fence with intent, single deep exhale, wipe sweat once, and start the ritual. Small routines prevent big panic.

Practice the re-start before it matters

Re-starts feel strange if you never do them. Build two short heat sessions into your week for the next month. Here are drills that simulate the rule and its demands.

1. Ten-minute break simulation

• Play two high-intensity sets to four games with no ad points and a tiebreak at 4-all. As soon as the second set ends, start a timed 10-minute break. Follow your script exactly, including cooling vest, ice towels, and the coach brief. Start the third mini-set to four with a scoreboard handicap so both players care about the opening two games. Track first-serve percentage and unforced errors in the first two return games after the break.

2. Heat ladder intervals

• On a warm day, do five blocks of 6 minutes rallying and points, 2 minutes changeover routine. Wear a chest strap or smartwatch. The goal is not a peak heart rate. It is the speed of recovery. Try to drop 25 to 35 beats in the first minute of each changeover using your breathing pattern. Note the best and worst block.

3. Serve plus one under fatigue

• After a 20-ball feeder drill, step to the line and play 12 serves to your two heat patterns. The coach calls location, you call first-ball target before the toss. Score yourself. If you miss the serve or the plus one, it is minus one. If you make both, it is plus two. Reach plus eight before you move on.

4. Return re-entry

• Right after the 10-minute break simulation, start with eight returns in a row, alternating deuce and ad. The server aims body. Your only goal is depth to the middle. Then play a two-ball rally. This resets timing without chasing lines when legs still feel heavy.

5. Hot tiebreak protocol

• Play a first-to-seven breaker immediately after a 6-minute high-ball rally drill. The coach gives exactly one cue at 3-all and nothing else. This builds the habit of short, clear information under heat.

6. Foot care and friction control

• Mid-session, change to dry socks and swap wristbands. It takes 30 seconds and prevents blisters and slippery hands in the real thing. Practice it so you are fast on match day.

Logistics that make the plan real

• Cooler management: pre-freeze two large gel packs and one slushy bottle per player. Label everything. Put the vest on top so you do not go digging.
• Bench setup: fan clipped to the fence, towels in reach, bottles in a standard order from left to right. The fewer decisions, the better. For equipment details, review our heat playbook for gear setup.
• Sunscreen and glare: apply at least 20 minutes before warm-up. Reapply during the break only if you can do it without getting lotion on palms or grip. Keep a small alcohol wipe to clean fingers if needed.
• Communication: agree on a single word that means call the break if the WBGT is at threshold near the end of the second set. You do not want a five-sentence debate at 5-4.

For coaches and parents: spotting red flags

• Coordination drops first. If footwork looks sticky or split steps vanish, push cooling even if the athlete insists everything is fine.
• Mentally, scattered eyes and slow decisions are early signs. Use the Heat Card to narrow choices.
• If cramps hit, the break is not a magic wand. Reduce swing size for three to four points and buy time. Make first serves, avoid emergency sprints, and get another changeover under your belt while sodium and fluid start to work.

Off-court training that pays off on hot days

Off-court training is the most underused lever in tennis. OffCourt unlocks it with personalized physical and mental programs built from how you actually play. To prepare for heat, build a two-phase block:

• Acclimation block: across 10 to 14 days, add short hits at the hottest safe part of your day, keep intensity modest, and increase duration gradually. The goal is to sweat earlier, reduce salt concentration in sweat over time, and learn your personal signals.
• Heat skills block: insert breathing drills, isometric holds, and light circuits between point-pattern work so you learn to make good decisions at elevated heart rates. Track heart rate recovery between reps.

Pair these with nutrition practices. Start the day hydrated, preload a light salty snack 60 to 90 minutes before play, and set your in-match sodium plan so the 10-minute break is just a scheduled top-off.

Timely takeaways for the swing after Australia

February and March tennis can be brutal in the sun and humidity. Dallas, Delray Beach, Acapulco, Rio, Santiago, Indian Wells, and Miami each bring a different mix of heat, glare, and breeze. Here is your checklist for the next month:

• Build your Heat Card now and laminate it. Put it in the same pocket as your ice towels.
• Do one 10-minute break simulation per week until it feels routine.
• Know your sweat rate within a 0.2 liter per hour window. Set sodium to match.
• Pack a cooling vest and fan for every day match on outdoor courts. Treat them like an extra racquet.
• Decide two serve patterns and one return position for the first two games after any break.
• Use OffCourt to program the acclimation and heat skills blocks so off-court work lines up with your match plan.

The bottom line

The 2026 Heat Rule does not just protect players. It creates a predictable, coachable moment in the heart of the match. The winners will be the players who treat those 10 minutes like a craftsman treats a tool. You already practice returns, serves, and patterns. Now practice cooling, hydration, and re-starts with the same seriousness. Pack your gear, write your Heat Card, and run the script. When the umpire calls time, you will stand up cool, clear, and ready for the first ball of the deciding set.