01:14 - Source: CNN
What NOT to do in a heat wave

Story highlights

Extreme heat is affecting tennis players at the US Open

A policy allowing players to take a break during their matches was announced Tuesday

CNN  — 

Scorching temperatures took a toll on athletes competing in the US Open this week. For the first time in the event’s history, an extreme heat policy was implemented to help tennis players cope with temperatures nearing 100 degrees Fahrenheit.

The policy allowed men to take a 10-minute break between the third and fourth sets if a player requested it. The rule has previously allowed players in the Women’s Tennis Association Tour to take a 10-minute break after the second set. The USTA has urged fans to take precautions when dealing with the heat as well, encouraging them to stay hydrated, apply sunscreen and seek shade.

“I don’t believe that we will have a concrete, written policy, if you will, on the extreme heat for the men until after this US Open as we see what is happening,” Chris Widmaier, managing director of corporate communications for USTA, said in a statement. “We will be doing this on a case-by-case basis.”

The Northeast has endured a heatwave this week. At the United States Tennis Association Billie Jean King National Tennis Center Flushing, New York, high temperatures reached 97 and 98. Typically, the area averages one day at 95 degrees or above during August, and only four days a year that are 95 degrees or hotter.

New York remains under a heat advisory Thursday, although today will be the last day with highs near or above 90 degrees. Heat advisories are issued when the combination of heat and humidity make temperatures feel like they’re approaching 100 degrees for two or more days, or 100 degrees or more for any length of time, according to the National Weather Service. The Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air-conditioned environments. Friday will see temperatures back down in the mid-70s.

Exerting yourself in such high temperatures can lead to heat-related illnesses, like heat stroke – which can be deadly.

Five players retired due to the heat on Tuesday. Alize Cornet, from France, told the on-court doctor she needed to vomit and felt pain in her head and bones. Cornet said the conditions had been a “nightmare.”

Novak Djokovic said he was "survival mode" for most of his second-round match, played in scorching heat and humidity at the US Open in New York.

“I think we should have a heat rule, it’s not healthy to be out there getting dizzy and stuff and the poor ball kids out there,” said Australian Nick Kyrgios. “There should definitely be a heat rule looked at and put into place.”

But not all of the players felt that way.

“There’s really nothing you can do but try to hydrate the best you can so your body is holding onto the water and you’re not letting the water go out so fast,” Venus Williams said. “That’s what leads to cramps and it’s definitely not easy out there. So the thing that makes it fair, though, is every single person is playing in it.”

On court Tuesday after defeating Marton Fucsovics, Novak Djokovic said, “I want to thank the US Open for allowing us to have the 10-minute break, because we both needed it.

“We were naked next to each other in the ice baths after battling for three sets, and it was a magnificent feeling, I must say.”

Ice baths are the best way to lower core temperatures, said Dr. James Winger, Loyola Medicine sports medicine physician. In 10 minutes, the players could expect their core temperature to go down by one degree Celsius.

In February, a panel of national experts in emergency and sports medicine was organized by the Korey Stringer Institute to identify the best practices in addressing heat stroke in athletes. The institute was named for a Minnesota Vikings player who died from heat stroke during training camp.

The panel recommended cooling athletes in a tub of cold water at the event, rather than transporting them to a hospital or another site.

“When doctors serve in sporting events as medical directors and team physicians, they must be prepared to cool onsite,” said Dr. Jolie Holschen, associate professor in the department of emergency medicine at Loyola University Chicago Stritch School of Medicine. “We also want to give emergency medical services the leeway to cool the patient before transport, when superior cooling methods are available. EMS directors should build this into their protocols and standard operating procedures.”

Mikhail Youzhny of Russia struggled with heat exhaustion during a match at the US Open.

Avoiding heat-related illnesses

The warning signs of impending heat illness include high body temperature, a fast strong pulse or skin that is hot, red, dry or damp, according to the Centers for Disease Control and Prevention. Symptoms include headache, dizziness, nausea, feeling confused or passing out.

There are two types of heat stroke. “One is called exertional heat stroke,” said Dr. Corey Slovis, a professor and chair of emergency medicine at Vanderbilt University Medical Center. This commonly affects athletes, such as football players or road racers in a tight pack. They exercise strenuously and their bodies can’t dissipate the heat fast enough.

“More commonly, and what was seen in this case is the classic heat stroke – passive heat stroke – where people become increasingly dehydrated,” said Slovis.

“We normally get rid of excess body heat by sweating and we evaporate and we lose heat via evaporation,” said Slovis. With dehydration, though, we “lose the ability to sweat, the body loses the ability to get rid of heat, and so body temperature rapidly rises.”

But what about athletes? How can they cope with the heat when playing something cardio-intensive like tennis?

“Highly conditioned athletes are the last persons who we would think might suffer effects from the high temperatures and humidity,” said Dr. Robert Glatter, an emergency physician at Lenox Hill Hospital in New York City.

“But they are at risk as well when the heat index rises. Keeping ahead of their thirst is the key, not just drinking when they feel thirsty,” he said. “Taking breaks is essential when intensely exercising in the heat for more than one hour. This includes rest, finding shade from the sun, and drinking water mixed with sugar and electrolytes. Salty pretzels, fruit and nuts are always a good option if you don’t have access to a drink with sugar and electrolytes.”

Slovis does not believe playing in the heat is worth the risk.

“My bias is that it is silly to play in 100 degree temperatures,” he said. “The risk of heat stroke, collapse on the court, acute kidney injury and a serious fall as one collapses from the heat are just not worth it. Why not postpone for a few days, play only at night or play in closed air conditioned stadiums when available?”

Slovis also noted that the venue for the Australian Open in Melbourne can close the roof for heat, but not the venue for the US Open.

Not being acclimatized to the heat and humidity of the area may be the biggest issue for tennis players, said Winger, the Loyola Medicine sports medicine physician. Some are used to training or playing tournaments in these conditions, but it could be a shock to others.

Get CNN Health's weekly newsletter

Sign up here to get The Results Are In with Dr. Sanjay Gupta every Tuesday from the CNN Health team.

Tennis players are at a high risk for developing high internal temperatures and should pay attention to how they’re feeling. Winger also warned that overhydration cannot save someone from heat illness.

Winger has advised marathon runners in the past to pull back if they start feeling unwell, but it’s different in head-to-head competition.

“Just understand that you will not be able to perform to same level in extreme heat as without extreme heat,” Winger said.

Danielle Rossingh, Susan Scutti, Brandon Miller and Judson Jones contributed to this report.