Ice towels and thermal stress techniques: how players deal with heat at Wimbledon

The Guardian

a day ago

'It was a bit of a shock to the system,' according to Cameron Norrie. For the German player Eva Lys, the conditions were 'really, really tough'. Jessica Pegula, meanwhile, said the weather was 'just like Florida'. The hottest-ever start to a Wimbledon fortnight has left a mark on players and spectators alike, and raised questions about how the tournament adjusts to a rapidly warming future.
The numerous measures put in place to deal with the heat of the past week were not hard to spot at SW19. The most obvious was the mass deployment of ice towels, rolled out to every court and wrapped around the shoulders of players at changeovers to aid the process of cooling. Described by Wimbledon's official channels as a 'critical welfare operation', what had previously been an item available only on request was scaled up so that, on day one alone, 145 towels were stuffed with ice cubes, stored in plastic bags for hygiene and distributed around the courts.
For spectators, the All England Club also expanded the number of water points in the grounds, increased the amount of available shade and used the public address system to relay frequent messages over the importance of hydration and sunscreen. For staff, shift patterns were changed to limit exposure to heat. For ballboys and girls there was the adoption of a 'beau geste' approach, adapting the uniform to include new headwear that covers the neck as well as the head, with 'cooling scarves' underneath.
On top of all this came perhaps the most significant sporting innovation, the introduction of a 'heat rule' that would mandate the checking of on-court conditions before a match and allow players to request a 10-minute break in the middle should the Wet Bulb Globe Temperature, a measure which incorporates heat, humidity and surface temperature, exceed 30.1C.
The heat rule was not activated on Monday or Tuesday but its existence carries a symbolic message: that in 2025 even the verdant surrounds of Wimbledon, a place often associated in the public imagination with drizzle, can't avoid the risks of extreme heat. 'The players are used to competing in these sorts of temperatures', said the chief executive of the All England Club, Sally Bolton.
'There is a heat rule available for them, which we'll implement if necessary. For fans attending, those Brits who are a bit less used to these sorts of temperatures, we're offering the same advice as the medical professionals – cover up, wear a hat, light clothing, wear sunscreen, make sure you're hydrated. We know it's your opportunity to watch some amazing tennis, but taking time off the court and out of the sun is really advisable.'
Dr Lee Taylor is a reader in exercise and environmental physiology at Loughborough University and an expert on the effects of heat in elite sport. He says the risks to players are increasingly well-understood and being responded to, but that a focus on short-term cooling measures does not provide the greatest protection to their health and performance.
'Short-term measures are about looking to alleviate some of the thermal stress,' he says. 'You're guzzling something cold, you're putting ice on you briefly during a match, but these measures have very limited power to change the body temperature for a high-performance athlete during intense competition. Instead we're stimulating what we call psychophysiological responses, we're actually tricking the brain into thinking that we're cooler.'
For the body to more fully adapt to unusual heat, Taylor says a fuller process of acclimatisation [natural heat exposure] or acclimation artificial heat exposure] is required. 'When we can't access a naturally hot environment to perform acclimatisation, we rely upon acclimation', he says. 'Acclimation is an artificial process, where you simulate a hot environment – you'll have seen athletes training in a hot box for example. The gold standard here is to expose athletes to these conditions 10 to 15 times to give them the best protection prior to a competition. The challenge with elite athletes is we just don't have the luxury of those 15 consecutive exposures because they're so busy competing, training, travelling, doing press, suffering from illness, injury, all of these types of things.'
Taylor says that adding acclimation to a regular training regime would not be harmful and could in fact offer improvements in performance. 'We're getting some pretty good evidence now that being heat acclimated or acclimatised can increase haemoglobin mass, which is one of the many determinants of endurance performance,' he says.
But tennis stars at this time of year are often already engaged in another kind of acclimatisation, to the unique grass court surfaces of Wimbledon. They also travel the world between varying climates and, clearly, elite athletes are highly motivated and push themselves very hard, often ignoring heat-related symptoms. There are clear challenges for making elite sport less exposed to the risks of extreme heat, but the sense is growing that they cannot be avoided for ever. 'The number of heatwaves, including their severity, intensity and duration are increasing', says Taylor. 'Players across all sports, including tennis, will be playing more competitions in extremes of heat. It's inevitable. '