Too Hot to Race: How Does Excessive Heat Affect Horse Racing?

Horse in sunlight

High temperatures and sport are two things that generally do not mix very well. Concerns surrounding the scorching summer temperatures in Qatar led to the 2022 World Cup being pushed back five months. For the 2020 Tokyo Olympics, although this took place in the summer as normal (of 2021 due to the global health crisis) several events had to be rescheduled due to the heat and humidity.

With abnormally high temperatures being seen on a more frequent basis, recent years have seen an increased level of disruption to sporting schedules. Horse racing is no exception either as there have been instances of meetings, across the globe, cancelled due to especially warm conditions. Although this only represents a tiny minority of all meetings, this is not to say that we will not see further cancellations during future years. The sport is used to dealing with postponed and cancelled meetings due to waterlogged tracks, snow and frozen ground, but do we now have to expect a new normal of action regularly called off due to high temperatures too?

How Hot Is Too Hot for Racing?

Sunlight on horse hooves

Usually, horse racing governing bodies do not set a specific temperature limit which dictates if racing can or cannot take place. This is because various other factors need taking into consideration aside from just the temperature.

Cloud Cover & Humidity

For starters, you have to consider if there will be much cloud coverage as racing while handed shade coverage will be noticeably more pleasant. You also, and more crucially, have the humidity aspect to think about, as the higher the humidity, the more difficult it is for horses to cool themselves down.

Temperature Increase

A final important aspect is the jump in temperature. According to the BHA Equine Welfare Integrity Officer Jeremy Willis, horses do have a decent ability to acclimatise in heat and can handle it quite well providing they are given time to adjust. The trouble arises when the temperature suddenly jumps up, by around 10C or more, from one day to the next, as this would end up being a major health risk. According to James Given, the BHA’s director of Equine Health and Welfare, horses would not be able to cope with such a sudden increase.

Some Horses Used to Hotter Temps

Trainer Christophe Ferland, who has his base in the lower parts of France also supported this point when a heat wave gripped France in June 2022. He said “it’s only 38 degrees – we’re used to it here in the south west… it hasn’t stopped us running”. It is not complete business as usual though in such heat as Ferland himself admitted. The trainer noted he had been taking his horses out earlier, training them for less time and making sure they had regular showers.

Case By Case Basis

So, to answer the question, everything will be judged on a case-by-case basis. It is possible for a meeting to be cancelled due to heat, only for a mildly warmer meeting to get the green light at a later point. Generally speaking though, when temperatures reach the mid-30s then this point where you can expect cancellations may occur, especially if such temperatures are relatively uncommon for the area.

Type of Race Also Important

Another factor to consider is the nature of the race. Whilst such high temperatures are rare during the National Hut season, we certainly can’t rule them out. Whilst 30c or more might be ok for horses running a six-furlong sprint on the flat, the risk to the health of the horses would be far greater if they were being asked to take on the four and a quarter miles, and testing fences, of the Grand National, for example.

What Is the Risk with Heat?

Cooling down a horse
Ivan Radic /

Horse racing in extremely warm conditions poses a bigger threat to horses than it does to jockeys. It certainly would not be a pleasant experience for any jockey, as they are made to work during races (and wear long sleeves) but it is the horse that works much harder. In order to stop them overheating during races, horses, much like humans do, end up sweating. It is sweating that accounts for around 75%-80% of heat dissipation, so it is the most effective tool available to the animals.

High temperatures trigger the need to sweat more but this can be very challenging if there is both no wind and the humidity is high. Sweat will not evaporate and this process and the surrounding air will not cool the blood that is brought close to the skin. A horse may be able to complete a race, in a respectable time, in such challenging circumstances, but the real danger comes after it has crossed the finishing line.

Potential Organ Failure

For a typical race, a horse will lower its temperature, heart rate, etc. within 30 minutes after it has finished galloping. If conditions are so hot that the horse cannot do this, problems can occur such as the failure of one or other organs. If its internal temperature reaches as high as 40.5C then blood supply to the muscles may shut down, meaning a very high risk of severe and permanent damage.

It is for this reason why after either warm or particularly arduous races (such as the Grand National) horses are covered in a bucket, or several buckets of cool water. This helps them reduce their temperature quicker, significantly decreasing the risk of any internal problems arising. On hot days, horses may take these ‘showers’ on multiple occasions to ensure they do not suffer from heat stress.

These showers are especially important when you factor in that larger mammals struggle to get rid of the heat compared to smaller ones. Horses have a bigger body weight to surface area ratio, which is great in the winter as it enables them to retain heat, but means that in the summer they cannot lose it as quickly. The danger temperature, when the risk of heat stress is significantly elevated, is on days when the ambient temperature is 35°C or above, or the Wet Bulb Globe Temperature is 26°C, according to the Thoroughbred Racing South Australia’s hot weather policy.

Cancellation in the United Kingdom

Horse racing union jackIt is an uncommon sight to see horse races cancelled due to heat (and humidity) in Britain but there have been some recent examples. In 2018, Cheltenham abandoned one long-distance event during what was one of the hottest April days for many years. This unprecedented decision came after several horses were found to be suffering from heat stress and another runner died earlier in the day (the cause at the time was not established). Temperatures at the meeting were around double the monthly average, around 28 degrees, and organisers felt this was extremely dangerous for a three-and-a-quarter mile trip.

The following year, Southwell cut one meeting two races short as temperatures reached 36 degrees. There was also a wave of cancellations in the summer of 2022 with many parts of Britain hitting temperatures close to 40 degrees. The BHA made this call several days in advance, following the Met Office’s decision to issue a ‘Red’ extreme heat warning. This resulted in of five meetings, across two days, being scrapped, with all courses located within or close to the red zone.

The BHA’s decision was met with virtually no opposition and it was hoped that the races could be rescheduled at a date in the near future. Three of the cancellations occurred at ARC courses but the group’s Managing Director, Mark Spincer said they ‘fully support(ed) the decision’, believing it was in the best interests of all involved to abandon the full card. Though something of a secondary risk, there is also the safety of the fans to consider on such days, especially give many will be consuming alcohol.

Cancellations in Other Countries

Cancellations are not limited to Britain either, in 2019, a meeting at Auteuil, in France, did not take place due to a heatwave that swept the nation, with temperatures exceeding 40 degrees. Australia is also relatively familiar with heat-rated abandonments. Victoria had to scrap a meeting in January 2018 while Newcastle (near Sydney) did the same two years later. This later cancellation came just shortly after the Valley in Melbourne called off a meeting as temperatures were expected to go as high as 43 degrees.

What Measures Are Taken to Combat the Heat?

Spraying horse down with water

The easiest way to avoid heat-related disruption in horse racing is simply to avoid times where it is most likely to be a problem. Lots of horse racing takes places in the United Arab Emirates but only between October and April, so not during the extremely hot summer months. Of course, you can still see potentially dangerous temperatures during this seven-month period but the odds are much, much lower.

Organisers may also look to adjust start times, hosting races outside the hottest hours of the day, whether this is before or afterwards. This may not always be possible but generally speaking, evening meetings, which you often find in the summer, face a reduced risk of cancellation due to heat as temperatures will have usually dropped by the time of the first race.

If the day happens to be especially warm, there are measures that can be implemented to ensure horses stay safe. When Southwell was expecting 31-degree temperatures for a meeting in July 2022, they ensured they had enough BHA vets to check all runners before racing. Additionally, the course ensured they had ample cold water so horses could be frequently showered. Cooling options such as cold water and ice were also made available to stable staff and others to ensure those working at the course stayed safe too.

On a day forecasted to be rather roasting, you can also expect trainers to shun making any long journeys. Travelling across the country, in a small, metal box, on a hot motorway, would not be a pleasurable experience for any horse, so extra considerations are given to the amount of travelling, and when the journey is taking place. This not only make sense from a welfare perspective but from a performance once too as a heat-exhausted horse is unlikely to perform well.

Speaking of performance, you might think that it is sensible to keep a horse ‘fresh’ for as long as possible by sticking it in a cool, shaded area before its race. You would then let the horse out only when required, limiting their time in the worst of the heat. This would be a mistake though as the sudden change in temperature when a horse gets up to full speed will end up increasing its risk of heat stress. Any horse should be given the chance to acclimatise to the heat (while being intermittently cooled down) before competing for their own safety.

How Does Heat Impact Performance?

Horse racing in Del Mar, California
Horse racing in Del Mar, California (Byron Hetrick /

For shorter races, heat should not have too much of an impact. For longer distance events though, you can expect any race run in high-temperatures to be done so at a slightly slower pace. A study from the University of Roehampton found that heat impacts the speed of horses more so than humans. Admittedly, they found this by looking at times in the extremely long-distance (30km) man v horse races, rather than a distance you might see a thoroughbred horse compete over, usually no more than 6.5km.

Nevertheless, it still highlights the point that horses do feel the heat. According to the Australian Veterinary Association, for every minute of exercise, a horse produces enough heat to increase its body temperature by 1 degree. While a sprint race could easily be over in a minute, a two-and-a-half mile flat race can take close to five minutes.

The type of surface a horse is racing on, during a hot day, can also impact the speed of the race, for better or for worse. One 2010 study looked at how heat impacted race times on a synthetic surface by looking at results at Del Mar in California. The study showed there was a definite correlation between the temperature of the track and the speed of the horse. It was theorised that this was at least partly because the track exceeded the point at which it experiences a thermal transformation.

Conversely, on a grass track, a spell of hot (and dry) weather can led to the ground drying up and this can lead to a faster racing surface. Ground staff will intervene by watering the course if the soil become too dry but at times this may not make a huge difference. For speed purposes, a track with an official reading of ‘firm’ is optimal, followed by the more commonly seen ‘good to firm’.