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Just not cricket – how climate change will make sport more risky

Heated contest: Mitchell Johnson and Steve Smith try to cool down during the Brisbane test in December 2014. AAP Image/Dave Hunt

Sport is fundamental to Australia’s society, culture and economy. But how would we cope when the rising heat threatens some of our most beloved pastimes?

A new report from the Climate Institute urges sports administrators to take the issue of heat stress seriously and to take steps to safeguard players, both professional and grassroots, from the health dangers.

Sport is good for us

As the new report (on which I was an advisor) points out, 80% of Australians aged 15 and over engage in sporting activities, more than two-thirds of schoolchildren play organised sport outside school, and more than 7.5 million Australians attend at least one sporting event a year. Each year, sport contributes more than A$12.5 billion to the economy and employs more than 75,000 people.

The documented benefits extend beyond mere economics. Sport guards against obesity, cardiovascular disease and stroke, respiratory disorders, cancer, and type-2 diabetes, and boosts fitness, strength, mobility, and independence in later life. It aids mental wellbeing, reduces stress, anxiety and depression, teaches fair play and leadership skills, builds self-esteem, and helps meet new friends and mentors.

Add to that the national feelgood factor when one of our sporting stars excels on the world stage, and it’s fair to say that sport is a good thing.

It is getting hotter

Revised climate projections released last week by CSIRO and Bureau of Meteorology predict that by 2030, temperatures could be 1.3C above the average for 1986–2005. By 2090, temperatures in Australia could be 2.8C to 5.1C higher if greenhouse gas emissions remain high, while the frequency of days above 35C and 40C is set to increase.

Since 2001, the number of extreme heat records for daytime maximum temperatures in Australia have outnumbered extreme cool records by almost three to one, and very warm months have increased fivefold over the past 15 years. 2013 and 2014 were Australia’s hottest and third-hottest years, respectively.

Melbourne’s hottest days are already 2C warmer than in the past. It’s clear that we need to prepare for even hotter summers.

Heat is lethal for people exercising

The heat risk from exercise is affected by weather conditions such as temperature, humidity, wind speed and sun exposure, and by other factors including exercise intensity and duration, fitness level, and acclimatisation. Problems arise when the body generates more heat than it can offload to the external environment, causing core temperature to climb.

Almost 80% of energy produced by muscles is heat, and intense physical activity can increase heat generation tenfold. At rest, the body’s normal core temperature is between 36.2C and 37.2C. Physiologists warn that if the body reaches beyond 39.2C, exercise must be stopped and cooling initiated, although body temperatures of 40C have been recorded in elite athletes.

Acclimatisation and fitness increase heat tolerance, but not indefinitely. Ultimately, hyperthermia results in reduced heart performance, low blood pressure, and the risk of organ damage and death.

Humans are not built to exercise in hot weather: athletic capacity peaks at air temperatures of just 11C, and declines sharply between 21C and 31C. Temperatures beyond 30C bring the risk of hyperthermia and heat stroke. Humidity makes the risk worse by reducing the effectiveness of sweating.

Few sports are without risk in summer heat. Heat stress can even occur in a hot swimming pool. Endurance sports such as gruelling tennis matches, marathon races and cycling tours are especially hazardous, as are football codes and cricket.

Data on heat-related injuries in Australian sport are not collected, but US research reports a doubling of heat deaths from 1975 (eight deaths) to 2009 (18 deaths), with children of 13 and 15 among the fatalities.

What’s more, playing sport in extreme heat shifts the contest from one of athletic prowess to one of simple heat tolerance. Adopting a gladiatorial approach in which players are expected to play until they drop undermines the core spirit of sport.

Heated decisions

Who should make the call when enormous sums of money have been invested? It is very difficult for the players to opt out. With careers and lucrative sponsorships on the line, and world rankings at stake, the pressure to play on is extreme.

Yet the prospect of mass withdrawal initiated by players’ associations is also fraught. There will always be someone ready to take a gamble with their health if there is a whiff of a win by forfeit, so a group walkout by the players is unlikely.

The call must come from the event organisers. They may face conflicting loyalties between financial backers, the players and spectators, yet ultimately, they shoulder a non-negotiable duty of care to protect players’ lives.

High-intensity, hot weather events such as the Australian Open and the Tour Down Under, as well as early starts to the football codes, are potentially lethal. Local-level sports throughout Australian summers are also becoming increasingly risky to health. Further afield, FIFA, world football’s governing body, somehow deemed it appropriate to choose Qatar to host the 2022 World Cup.

The Climate Institute’s call to arms for all sporting codes to acknowledge increasing heat as a serious health threat is timely. As a nation, Australia needs to respond. To genuinely protect players, sports administrators must establish heat guidelines that take account of the physiological dangers of heat, and are also appropriately tailored to the physical intensity and fitness levels within their game.

Monitoring weather conditions and players’ welfare, rescheduling games when required, increasing rest breaks and allowing for rotations of team members, fastidious attention to hydration, providing shade, fans and cool vests – these are all minor adjustments that could save a life. It is also vital to ensure that trained people are on site who are equipped to recognise and treat heat illnesses.

Sometimes medical emergencies are unavoidable in sport. But we shouldn’t be inviting athletes to suffer foreseeable ones such as heat stroke.

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