Playing tennis in summer heat: how to stay safe on court

Why the court is hotter than the air

The air temperature on a forecast is measured in the shade. A hard court is dark acrylic over asphalt or concrete, and in direct sun it soaks up heat and gives it back. Standing on one in the afternoon you can feel the warmth coming up through your shoes, and the surface itself can be much hotter than the air above it. How much hotter depends on the colour, the sun and the wind, so it varies from court to court and day to day.

Clay and other loose surfaces stay cooler under the same sun, and shade, whether from trees, a building or a fence cover, makes a noticeable difference. Humidity matters too. When the air is damp, sweat evaporates more slowly and your body cools less well, so a muggy 90 degrees can be harder to play in than a dry one. Our guide to court surfaces explains how each one differs.

Pick your time of day

The easiest fix is the hour. In hot weather, early morning and evening are the best times to play, and the middle of the afternoon is the worst. Courts that are shaded in the morning or the evening are worth knowing about.

Evening play depends on lights, and not every public court has them. Our guide to playing tennis at night covers how lights usually work. In the court directory a listing shows whether a court has lights, where we know it.

Water and electrolytes

Start drinking before you play, not once you feel thirsty. Drink during the session, a few mouthfuls at each changeover, and keep going afterwards. A full bottle is a minimum for an hour in the heat, and many players bring more. If you are sweating a lot or playing for a long time, a drink that contains salt and other electrolytes can replace some of what you lose, but plain water is fine for a casual hit.

Do not wait for symptoms. Thirst, a dry mouth, a headache or dark urine are late signs that you have already fallen behind. Alcohol and a lot of caffeine before a session do not help.

What to wear

• Light clothing. Loose, light-coloured, breathable fabric reflects more sun and lets sweat evaporate. Many tennis clothes are made for this.
• A hat or visor. It keeps the sun off your face and out of your eyes. Take it off when you serve if it gets in the way.
• Sunscreen. Put it on at least 15 to 30 minutes before you go out and reapply if you are sweating heavily. Choose one that says it is water-resistant, and keep it off your palms so that your grip is not slippery.
• Sunglasses. They cut glare off the court, though some players find them awkward at first for tracking the ball.

Our guide to what to bring to the court has the full bag list.

Rest between games

The rules allow a short break at each changeover, and in the heat it is worth using all of it. If there is shade by the court, sit in it rather than on the bench in the sun. Drink, wipe your face and slow your breathing. If there is a water fountain, a wet towel on the back of your neck helps you cool down. If you are playing a long match, take a longer break between sets if the other player agrees, and agree on it before you start.

Do not try to play through feeling bad. Playing a point more is never worth the risk.

How the ball and strings behave

Heat changes the equipment as well as you. The air inside a tennis ball warms up and pressure rises, so balls generally feel livelier, fly a little faster and bounce higher in hot weather than in cold. If you are serving long, that may be why. Keep the can in your bag or in the shade rather than baking in a car.

Racquet strings are affected too. Strings tend to lose tension faster in heat, so a racquet that felt crisp in the morning can feel looser and less controlled after a few hours in a hot car or in the sun. Keep your racquet out of the car and out of direct sun when you are not playing.

Heat exhaustion and heat stroke

Know the warning signs, and know that they can look similar at first. This is general information, not medical advice.

Heat exhaustion

Typical signs are heavy sweating, a fast pulse, muscle cramps, dizziness or a headache, nausea, tiredness and weakness, and pale, clammy skin. The sensible response is to stop playing at once, move to shade or an air-conditioned place, lie down or sit, loosen or remove extra clothing, cool the skin with cool water or a wet cloth, and sip water if you are alert. If you do not feel better soon, or symptoms get worse, get medical help.

Heat stroke

Heat stroke is a medical emergency. Signs include confusion, slurred speech, odd behaviour, fainting or collapse, a very high body temperature, and skin that may be hot and dry or still sweaty. Call 911 straight away. While you wait, move the person into shade, cool them with whatever you have, such as cool water, wet cloths and fanning, and do not leave them alone.

When indoors is the better choice

On the hottest days, or if you have a health condition that makes heat a risk, the safest choice may be to play somewhere air-conditioned. Our guide to indoor tennis explains how indoor courts work and what they usually cost. Whichever you choose, the map shows the courts near you and your playing partners, and the directory notes when a facility has indoor courts.