First week The French Open caused as many major upsets (two) as people collapsed on the court due to the heat.
Although temperatures in Europe are unusually high for this time of year, they are not as warm as the Sahara Desert in mid-summer. Yet a ball girl nearly fainted during a first-round match on Monday, while men’s player Jakub Mensik collapsed on the red surface at Roland Garros on Thursday after a five-set match, claiming his body “just turned off.” Players spent time between games sitting in the shade and placing ice bags on their heads and shoulders, all while trying to beat the oppressive heat.
To truly understand why players struggle with the heat on the court, you need to look at a little-known metric called wet-bulb temperature. This can be considered an improved version of the saying “it’s not heat, it’s humidity”, which is best suited to measuring the effects of heat on human health.
Temperatures ranged from the low to mid-90s (or high 30s for Celsius lovers) due to the “heat dome,” a persistent area of high pressure that traps sultry air and causes temperatures to rise. This is where the moist bulb temperature comes in.
The index “takes into account many aspects of environmental conditions, such as temperature, humidity, solar radiation and wind,” says Rachel Cottle, a postdoctoral researcher at Texas Health Presbyterian Hospital Dallas. “This is important because when we think about environmental stress, we need to consider all the variables that may increase the risk of heat-related illness.”
A moist bulb temperature of 30 degrees Celsius may not sound so bad, but it represents the beginning of the danger zone for human health. At this temperature, sweat does not evaporate as effectively as at lower temperatures. Cottle has conducted research showing that even hearty newborn people begin to experience problems when the moist bulb temperature reaches about 88 degrees Fahrenheit (31 degrees Celsius).
“Although athletes still have some limitations, their greater cardiovascular capacity and potential acclimation to high temperatures will cause them to have higher limits than non-athletes and non-acclimated people,” health researcher Kat Fisher said. “Shading and cooling the body with ice can help lower body temperature and limit the constant rise in temperature.”
Improved endurance isn’t all athletes care about when it comes to battling the heat. “Athletes and people who are in good shape sweat more, which helps them cool down better. They also start sweating earlier, so their bodies can start to cool down more quickly. Basically, athletes are more efficient sweaters,” notes Cottle, while emphasizing that even the most proficient sweaters walking among us mere mortals have their limits. Without sufficient rest and access to cooling, your risk of heat stroke or heart problems increases.
The French Tennis Federation reportedly has two wet-bulb thermometers on Roland Garros courts and plans to extend breaks between sets and even cancel matches if they exceed a certain threshold. Thermometric temperatures around the globe during the French Open have not yet reached this level, even though some matches are played at the hottest times of the day on courts without shade. However, on-court health concerns have highlighted the risks and temperatures are expected to rise even higher in the coming days as a heat dome intensifies over the region.
The other three Grand Slam tennis tournaments – Wimbledon, the Australian Open and the US Open – have warm weather plans in place to allow players to rest and frigid off longer. To implement them, all events rely on moist ball measurements.