The new rule in plain English
Starting in 2026, the ATP will use the Wet Bulb Globe Temperature (WBGT) to decide when heat protections kick in. Think of WBGT as a smarter thermometer that mixes heat, humidity, wind, sun, and radiation to estimate heat stress on your body. When WBGT hits a specified level during a best of three singles match, action changes in two important ways:
- If WBGT reaches 30.1 degrees Celsius during the first two sets, either player can trigger a supervised 10-minute cooling break after set two. Players can hydrate, shower, change clothes, use cooling aids, and receive coaching. This is codified in the ATP heat rule effective 2026.
- If WBGT climbs past 32.2 degrees Celsius, play is suspended until conditions improve. Grand Slams have their own policies, so expect differences at those events.
That simple change makes extreme heat predictable and tactical. You now know when a true reset is available, and you know the line where play stops entirely. For a deeper primer on thresholds and scenario planning, see ATP Heat Rule 2026 thresholds and tactics.
Why WBGT changes the chessboard
Heat does not just make you uncomfortable. It changes how your body produces energy and how your brain plans. Core temperature rises faster, sweat loss accelerates, and the cardiovascular system diverts blood to the skin for cooling. The result is a smaller energy budget for each point and slower decision making. In hot, humid weather, balls also travel through less dense air, which can make shots fly a touch quicker and deeper. On hard courts that combination rewards first-strike patterns and clean technique that wastes no movement.
With the 2026 thresholds, players and coaches can plan for two different games: one where cooling is still optional but useful, and another where the 10-minute break is guaranteed after set two if the trigger is reached. That certainty allows you to build routines now and rehearse them like set plays.
Make the 10-minute break a performance tool
Here is a minute-by-minute cooling break routine that any player can practice. Adjust the specifics to your physiology and event rules, but keep the structure.
- Minute 0 to 1: Exit the court efficiently. Hat off, wristbands off. Begin slow nasal in, long mouth out breathing while walking. This starts to lower heart rate.
- Minute 1 to 3: Sip 300 to 400 milliliters of a cool, salted drink. If tolerated, add a small ice slurry for faster cooling. Place an ice towel around neck and another across thighs. Sit in shade or a cooled area.
- Minute 3 to 4: Two-minute cold rinse or 60-second cool shower. Dry fully. Put on a fresh shirt and socks. Reapply rosin or grip powder if you use it. Switch to a new overgrip.
- Minute 4 to 6: Coach briefing. Keep it to one primary adjustment and one contingency. Example: “Serve 70 percent first serves, target deuce wide to open forehand. If opponent shifts wide, go body. Return position two feet deeper on second serve, chip middle and crash to backhand.” Keep the language short and vivid.
- Minute 6 to 8: Light mobility. Ten ankle rocks, ten hip openers, ten split step bounces. Rehearse the first two points out loud. Example: “Serve deuce wide, first ball forehand to backhand corner. Next point, body serve, look for forehand middle.”
- Minute 8 to 10: Top up with 150 milliliters of drink. Ten slow breaths, five count in and seven count out. Walk to the line with time to spare.
Pack for this routine. Bring two cooling towels, an extra wristband set, three dry shirts, two pairs of socks, two overgrips per set, and a small squeeze bottle for ice slurry. If your event allows, a lightweight cooling vest makes the first three minutes more effective.
Coaching in the heat: scripts that travel
Because coaching is permitted during the cooling break, plan what to say and when. Heat reduces attention span, so the message must be simple.
- Pre-match script: Write three hot day defaults on the player’s card. For example, “First serve percentage above 68, recover behind the baseline to the shade side, and play middle third on returns.”
- In-break script: Use one sentence for tactics, one for movement, one for mind. Example: “Work the deuce wide serve, then forehand to backhand; on defense, recover three steps deeper; breathe five in and seven out between every point.”
- Micro-cues after the break: First three games after the break, the coach or player repeats one clear cue before each point. Example: “Tall toss, smooth first swing.” Simplicity wins under heat stress.
If you want a broader plan that ties rules to training and fueling, see WBGT rules, training, and hydration.
Train to the policy: a two-week heat acclimation block
You can safely build heat tolerance in 10 to 14 days. The goal is to increase sweat rate efficiency, expand plasma volume, and reduce the rate of core temperature rise. Use a progressive ladder and monitor body mass change and symptoms. Stop if you feel dizzy, nauseated, or chilled.
- Days 1 to 3: 45 minutes easy hitting or footwork in warm conditions. Finish with 10 minutes of shadow swings in the sun. Keep heart rate in a steady zone you can hold a conversation in. Drink small sips every 10 minutes.
- Days 4 to 7: 60 to 75 minutes. Add 10 to 15 minutes of point play at the end. Practice between-point breathing and towel routines. Measure pre and post session body mass to estimate sweat loss.
- Days 8 to 12: 75 to 90 minutes. Add two blocks of five minutes of high tempo drills separated by five minutes of easy hitting in shade. Now rehearse the full 10-minute cooling break routine in the middle of practice, including a short coach briefing.
- Optional heat finishing: On easy days, sit in a warm bath for 20 to 25 minutes after training. This keeps core temperature slightly elevated to reinforce adaptation. Keep the water comfortably warm, not scalding, and hydrate before and after.
For juniors, limit the total daily heat exposure and ensure an adult monitors. For collegiate and pro players, build the block into preseason and again ahead of known hot events.
Hydration and sodium: numbers that actually help
Generic “drink more water” advice fails in real matches. Use a simple system that starts with your sweat rate and your sodium needs.
- Sweat rate: Weigh yourself nude before and after a session. Add the fluid you drank and subtract any bathroom stops. The difference is your sweat loss. Divide by hours to get liters per hour. Many players fall between 0.4 and 1.2 liters per hour, but measure yourself.
- In-match target: Aim to replace 60 to 80 percent of expected hourly sweat. For a 0.8 liter per hour sweater, that is roughly 500 to 650 milliliters per hour. Too much fluid can cause sloshing and bathroom breaks. Too little leads to performance drop and cramp risk.
- Sodium: Start at 500 to 700 milligrams per liter of intake. If you see heavy salt stains on clothing or get muscle twinges late, try 800 to 1000 milligrams per liter. Use sports drink powder, a measured electrolyte mix, or sodium capsules paired with water.
- Carbohydrate: In hot conditions, aim for 30 to 60 grams of carbohydrate per hour. That can be through a lightweight drink or small chews. Spreading fuel across changeovers keeps blood sugar stable as temperatures rise.
- Pre-match primer: Drink 5 to 7 milliliters per kilogram of fluid about three hours before the match, with 400 to 600 milligrams of sodium. If your urine is still dark one hour out, take another 3 to 5 milliliters per kilogram.
- Post-match: Replace 150 percent of what you lost over the next three to four hours. Include sodium and protein so the fluid stays in your body and muscle repair begins.
Practical on-court setup: two-bottle rule. One bottle is your electrolyte and carbohydrate mix, the other is cool water. Take three or four small swigs from the mix most changeovers and a small swig of water to finish. In the hottest matches, alternate a cool sip with a brief mouth rinse that you spit out to get a perceptual cooling effect without overfilling your stomach.
Between-point pacing and breathing that saves energy
The serve clock is your friend in the heat. Use it to lower heart rate between points and to maintain crisp execution.
- The 25-second rule of thirds: First eight seconds to reset gear and grip. Next eight seconds for breathing and posture. Final eight seconds to rehearse and step into your routine. Arrive at the line with five seconds left, not five seconds into the next rally.
- Breathing: Try 5 in, 7 out breathing through the nose on the inhale and the mouth on the exhale. Pair the long exhale with a soft jaw and relaxed shoulders. Between games, add three cycles of 4 in, 2 hold, 6 out while seated in shade. For techniques that scale under pressure, see breathwork that improves performance.
- Movement economy: Favor split steps and tight recovery lines over big hero sprints. If defending on a wide ball, recover diagonally to the shade side when possible. Small energy savings accumulate quickly in the heat.
- Towel and shade discipline: Use the towel lightly every changeover to wick sweat, then sit in shade. Keep your head and neck out of direct sun when you can.
Serve and return patterns when WBGT is high
When conditions are hot and humid, aim for serve-first patterns that produce a playable first ball and avoid long scramble rallies.
- First serve percentage: Target 68 to 72 percent. Trade a little pace for better location. Aim deuce wide to open the forehand and ad body to jam the backhand. Confirm whether the opponent is shading the wide side, then change to body or T.
- Second serve intent: Use a reliable kick or heavy slice that lands high and deep. Follow it with a big forehand to the middle third, not the line. That reduces risk and cuts off the opponent’s angles.
- Return of serve: Against big servers, move two steps deeper on second serves to buy time and chip middle with depth. The goal is to start the rally neutral without sprinting. Against slower servers, move in and block deep to the backhand, then look to take the next ball early and to the open court.
- Rally length target: Shape patterns to end 60 percent of your points within the first four shots without taking low percentage swings. Serve plus one to the body, return chip middle, approach off any short ball.
- Grip and toss management: Dry hands and new overgrips keep the toss consistent. If your toss drifts when sweaty, drop the height by a small margin so you can accelerate smoothly without chasing the ball in the sun.
Lightweight gear and cooling tools that matter
Every gram of moisture in your clothes and every degree of skin temperature influences feel and decision speed. Build a hot match kit.
- Apparel: Light colors, mesh panels, and quick dry fabrics. Many pros carry one shirt per set. Pack at least three and swap early, not only when soaked.
- Head and hands: A perforated cap and two wristbands per set help manage sweat flow. Keep a rosin or chalk pouch in your bag for grip if allowed. Bring six to eight overgrips.
- Foot care: Thin, breathable socks, foot powder, and a small blister kit. Change socks at the break if they are wet.
- Cooling aids: Two cooling towels, a spray bottle, and a permitted cooling vest if the event allows it. Some teams also carry a small battery fan for the bench area with tournament approval.
- Eyewear and sunscreen: Shaded lenses reduce squinting and neck tension. Apply sweat resistant sunscreen well before play so it can set and not drip into eyes.
- Strings and tension: Hot courts can play faster. Some players drop string tension by one or two pounds to keep the ball in the court when the air is thin. Test this in practice, not on match day.
Match management before the break
Because the break only arrives after set two if the trigger is reached during the first two sets, you need a plan to manage run rate before that pause.
- Start smart: In set one, build points with serve and first forehand. Avoid long cat and mouse rallies from neutral.
- Time in shade: On side changes, sit down immediately, take your first sip, then start your breath cycles. Do not stand and chat with your team across the court. Seconds count.
- Micro cooldowns: If allowed, pour a small amount of cold water on the neck and forearms at each changeover. This cools blood heading back to the core.
- Scouting the trigger: Have your team monitor the on-site WBGT display. If conditions are rising toward 30.1, accelerate towel and hydration routines in the last two games of set two to be ready to move into the cooling break efficiently.
Parents and coaches: build the heat team
Heat management is a team habit, not a player quirk. Assign roles.
- Coach: Leads the two-line tactical message during the break. Tracks first serve percentage and rally length to confirm the plan.
- Parent or manager: Manages ice, extra shirts, cold drinks, and replacement grips so the player does not wait for supplies.
- Hitting partner: Helps rehearse the break routine during practice. Plays simulated first two points after the break exactly as scripted to build confidence.
What serious amateurs should implement now
Even if you are not on tour, the policy teaches useful habits.
- Measure your sweat rate on a hot weekend and adjust your drink plan. Put the numbers on tape in your bag.
- Practice a 10-minute break routine once per week. Use a kitchen timer. Repetition makes execution automatic when you get a league heat delay or a tournament break.
- Create a hot day packing checklist and print it. Check items off the night before a match.
- Train with a two-week acclimation block ahead of your hottest event. If you cannot train in heat, use warm post-workout baths to supplement.
What changes if play is suspended
If WBGT passes the suspension threshold, treat the pause as a longer reset. Priorities are cooling, fueling, and tightening tactical clarity. Keep the same message structure, but review scouting clips if available. When the restart time is announced, begin your breath cycles eight minutes out and rewarm with elastic band work and a few dynamic moves so the first game after the restart is sharp. For context, see this Reuters summary of thresholds.
Use OffCourt to build and track your plan
OffCourt helps you map the acclimation block, program breath work between points, and generate a hydration plan tied to your measured sweat rate. Bring these elements into one routine you can rehearse and refine.
The real edge in 2026
A rule does not win points. Routines do. The ATP has made heat windows predictable. Players who practice a minute-by-minute break routine, who script short coaching messages, who know their fluid and sodium numbers, and who pace between points with intent will turn high WBGT days into advantage. Start rehearsing now. Print your checklist, rehearse the break, and test your patterns in the heat.