ATP introduces new extreme heat rule to protect players during men’s tennis matches

The ATP Tour is adding a rule to address extreme heat during men's professional tennis matches that will allow for 10-minute breaks during best-of-three-sets singles matches starting next season. It is similar to what was put in place on the women's circuit more than 30 years ago.

The ATP Board's approval of the new policy, announced on Monday, strengthens “protections for players competing in extreme conditions,” the tour said.

During the Shanghai Masters in October, some players called for the ATP to introduce guidance to help them in cases of extreme heat and humidity. Defending champion Jannik Sinner stopped playing a match there because of severe leg cramps; 24-time Grand Slam champion Novak Djokovic lamented the conditions after vomiting during a victory.

“It’s brutal when you have over 80 per cent humidity day after day," Djokovic said then, "particularly for the guys when they’re playing during the day with heat, with sun."

Tennis tournaments are heating up

An Associated Press analysis in 2023 showed that the average high temperatures felt during the US Open and the three other major tennis tournaments had steadily gotten higher and more dangerous in recent decades, reflecting the climate change that has fuelled record heat waves.

It tracked the thermal comfort index, which measures air temperature in degrees while also taking into account humidity, radiation, wind and other factors that affect how the body responds.

Looking at each Grand Slam event dating to 1988, the first year all four had 128-player fields for women and men. Collectively, the maximum temperatures at those tournaments had risen by nearly 3 °C.

This year, players saw the hottest start to a Wimbledon fortnight ever, raising questions about how to cope with the rising heat.

What is the new ATP heat rule?

The new ATP rule is based on the Wet Bulb Globe Temperature (WBGT), which takes into account the heat, humidity and other factors.

When the WBGT reaches at least 30.1°C in one of the opening two sets of a best-of-three match, either player is allowed to request a 10-minute suspension of play.

If the WBGT exceeds 32.2°C, the match will be halted.

During the breaks, players can change clothing, shower, hydrate or use other ways to cool off, under the supervision of ATP medical staff, and they also can receive coaching.

That ATP said the rule is aimed at “safeguarding player health, while also improving conditions for spectators, officials, ball persons, and tournament staff.”

The WTA first established a rule to protect players in the heat in 1992.

Grand Slam tournaments set their own heat policies. The US Open, French Open and Wimbledon also have rules based on WBGT readings, as does the tennis competition at the Olympics, which is run by the International Tennis Federation.

The Australian Open goes by something called the Heat Stress Scale.