Sports Competitions in Hot Climates  

Olympic Competition in Hot ConditionsClimate can have a significant effect on performance and all Olympic athletes must consider the climate their competition takes place in during their preparations. This is particularly the case for outdoor events as the competitions conditions cannot be controlled as well, and are left to the fate of the weather. These effects can have a beneficial or detrimental effect on performance, such as high altitudes, which makes it more difficult to breath but reduces air resistance. Different weather conditions will affect different sports in different ways, and it is important to understand what effects the weather and climate will have when it comes to competition and prepare effectively for it.

Perhaps the biggest factor for Olympic athletes, and that affects more than any other, is temperature. As the Olympics is held during the summer season, high temperatures are common, and during most Olympics very hot days have occurred during the three weeks. While indoor sports are able to control the temperature, athletes of outdoor sports must perform whatever the temperature is on the day, and therefore high temperature conditioning will likely be needed by most.

This is because hot temperatures can have a wide range of effects on performance, both in terms of the effects on the body and in some cases the dynamics of a sport itself. For example, a ball moves through the air differently at different temperatures, so for sports such as tennis playing on a very hot day can see the ball move at a different speed than on a cold one.

Physiological Effects

Whatever the sport, athletes need to generate large amounts of energy during competition and much of this energy is released as heat, rather than motion. With the body’s optimal functional core temperature within just a degree or so either side of 37°, this excess heat must be transferred out of the body. Efficient temperature control can therefore become vital for athletes even on days of moderately high heat exposure, and this is done through a combination of reducing heat generation where possible and more effectively removing heat that is produced.

The body removes the majority of heat from the body though the skin. The skin has a large surface area in contact with the air, and exposing it the air allows the heat to transfer from the skin to the colder air that surrounds it. The colder the air is than the skin, the quicker the heat will transfer from the skin and the easier it is to cool the body. However, as the air temperature increases, the longer it takes for this heat to transfer from body to the air and the harder it is for the body to cool. If simple exposure to the air is not enough to cool the body, then water is released from the skin in the form of sweat. This sweat is then able to absorb heat and eventually evaporate, or drip off, removing the heat from the body.

This system of removing heat from the body is highly effective at keeping the core body temperature around the 37° mark. However, water is vital for the body to function properly, and even just a 1-2% drop in body water can dramatically affect an athlete’s performance. The hotter the day, the more the body has to use the sweat cooling system to stay cool and the more water it loses. In most cases, athletes competing in hot conditions are dealing more with maintaining their hydration levels rather than worrying about their core body temperature.

Health Risks

There are a number of potential health problems associated with competing in hot climates, particularly in outdoor sports that require large and lengthy amounts of exposure and those in very hot conditions.

In most cases, even in hot conditions, the combination of the temperature difference between the skin air, and the production of sweat is enough to cool the body for the duration of competition. However, in some cases the outside conditions can prevent the body from cooling and can lead to the body heating to dangerous levels and cause a range of heat illnesses. This can happen even in cool climates if the exercise is of high enough intensity and duration, so in hot climates the risks are significantly higher, particularly for elite athletes where intensity of performance is at its peak.  

For the core body temperature to remain cooled, the temperature at the skin must be lower than that of the core of the body, particularly that of the circulating blood. Otherwise, the heat will not transfer from the inside of the body to the skin and then to the air. The skin, therefore, is limited in the temperature it can reach if the body temperature regulation systems are to work. The closer the air temperature is to that of the skin, the slower the heat transfer to the air and the more sweat must be produced to maintain temperature control. It is not uncommon for athletes to perform in outside temperature near to or above the core body temperature level of 37°, and in these very hot conditions the sweat systems go into overdrive. If the body cannot produce enough sweat quickly enough, then the risk of overheating is very real and can be dangerous.

If there is also a high humidity, this risk becomes even worse. As humid conditions already have a lot of moisture in the air, sweat is not transferred off the body into the air as quickly, impairing this heat reduction mechanism.

If there is a combination of very high temperature and humidity, the two main ways the body transfers heat to stay cool can be severely impaired, and the heat generated by the body during competition can become very dangerous, particularly for sports of long duration.

Usually the body’s defence mechanisms prevent us from getting to a stage where we overheat to dangerous levels. Our muscles stop working properly, as, for example, blood diverts from the muscles to the skin, and our level of activity is forced to reduce, causing us to produce less heat and giving our bodies time to cool. However, Olympic athletes are trained to push their bodies much further, not only physically but mentally. They are able to maintain performance at very high levels, overcoming the body’s natural mechanism which would reduce its work in most cases. This puts some athletes at much increased risk of overheating in hot and humid conditions, and has even caused death in some cases. It is important that an athlete competing in these conditions where there is a high risk of overheating are checked medically for any other conditions that may be compounded if overheating does occur. These conditions include acute abnormal blood pressure, heart conditions, concussions and migraine history, asthmatics and any other chronic conditions. Factors such as age and skin type are also important to consider.

Preparation and Management

With temperature very unpredictable, it is not possible to know the exact conditions come competition time, so preparing an athlete for the temperatures they will encounter at an Olympics is difficult. In some  places at certain times of the year, it very predictable that high temperatures will be experienced, however in many places, and particularly for the London Olympics, the potential temperatures are very wide, and to predict four years out is not possible.

However, there are things athletes can do even in a short time before an event and during competition to minimise the adverse effects of high temperatures, meaning planning can be finalised closer to the time when weather patterns are more predictable, though the longer the preparation time available the better.

Studies into the effects of high temperatures on fatal heat stroke showed that competition in more northern countries, like northern Europe, required a much lower minimum temperature to develop fatal heat stroke than ones taking place further south, and the minimum temperature for fatal heat stroke in late summer was much higher. This indicates that the body is able to adapt, with athletes from hotter countries adapted better to performing in hotter conditions, while after a summer of high temperatures the body is also better adapted at competing in them. This is significant as both short term and long term acclimatisation occurs.

This means that athletes can train their bodies to adapt to different temperature conditions, and can plan their preparations depending on where their competitions take place. For example, if an Olympics is taking place in a hot country close to the equator, where there is a very high probability that high temperatures will be experienced during competition, athletes will need longer exposure to these temperatures during preparation to be in best shape for their event. This may mean basing themselves in hot conditions for an entire season prior to an Olympics.

For London 2012, extreme temperature conditions and humidity are not as likely, so heat preparations can take place on a shorter time frame.

There are a number of different strategies in acclimatising for performance in hot conditions. The key principle is to gradually bring the intensity of performance up to the same as competition at lower temperatures over a suitable time frame. The time required to do this will depend on several factors. For hotter conditions, a longer acclimatisation will be required, as will for athletes who mainly perform in more moderate climates. The intensity required for competition is also important. Athletes whose sports require very high intensity exercise will require longer acclimatisation. A rating system has been devised as a guide to help with this.

  1. Endurance running in competition or training  (higher intensity/higher risk)
  2. Football codes and hockey
  3. Tennis
  4. Cricket (lower intensity/lower risk)

with 1 being the highest risk, and 4 being the lowest. In essence, competitions where there is high intensity exercise for long durations are at high risk (Endurance Running), with sports that have more breaks in high intensity exercise at reduced risk (tennis and then cricket).

Another key factor is an athlete’s fitness levels relative to their sport’s requirements. If an athlete is relatively unfit, then they will need to start their acclimatisation at high temperatures at lower exercise intensities and therefore it will take longer to acclimatise to the hot conditions. Therefore, athletes should already be highly trained before undertaking their pre-event temperature conditioning. Ideally, their intensity training should peak above that required for competition, as there will be some drop of in intensity during the initial stages of temperature acclimatisation. This is particularly the case where the preparation period is longer.

An important aspect of the preparation period is that it should be sport specific. It has been shown that event specific exercises during high heat exposure improves both cardio-vascular function and the body’s ability to maintain hydration levels. This is not surprising, as the body becomes more acclimatised to regulate the heat production that is specifically generated by their sport.

Improving technique and strategy can also be a key part of heat management. A more efficient technique that requires less energy and produces less heat will naturally reduce the risk of heat-related conditions, for example a marathon runner may work on their transition technique. For events where there are opportunities for reduced intensity or breaks, such as tennis, then finding ways to increase the amount of time spent performing low intensity exercise while maintaining performance can help reduce heat production. For example, taking a bit longer between serves and reducing movement speeds where possible.

On the day of competition, there are also a number of thing that can be done to minimise the effects of hot conditions.

Firstly, the competition organisers have a responsibility to look after the athletes’ safety, and things like appropriate scheduling and provision of fluids can significantly reduce the risk of overheating. The marathon is one of the events most at risk to its athletes in high temperatures, and it is often held early in the morning to avoid the peak day time temperatures, with water points throughout the race. Many sports and event organisers will take as many measures as possible to minimise the risks of high temperatures to their athletes.

The athletes themselves can also take measures on the day of competition to minimise the risks of the heat. Keeping the body well hydrated and cool prior to competition is a key factor in hot temperatures, and staying out of the sun as much as possible, as well as wearing protective clothing and water soluble sun cream can help significantly.

Athletes will also adjust their warm up routines. These will be of lower intensity and usually shorter duration in order to make sure that core body temperature is not elevated prior to the start of the event. However, it is important that the warm up is sufficient to stimulate the body’s temperature regulation systems so that they are working optimally at the start of competition. Making sure that the right vasodilation and some sweating have occurred is usually recommended, otherwise the core temperature will rise during the initial part of competition as the body’s systems start to kick in.

Taking on fluids during competition when possible is also important, and in very hot temperatures athletes should take on small amounts of water as regularly as possible, ideally with the addition of electrolytes but suited to the palate of the athlete.

Clothing can also be important. Sports clothing technology has significantly advance so that sweat is effectively moved away from the skin and evaporated, as well as helping to protect the skin from the sun’s rays.

Sun Exposure

Participating in sport outside in the sun for long durations can be a health risk due to the significantly increased exposure to harmful sunlight. Elite athletes preparing for and competing in an Olympics in hot conditions are potentially at even higher risk due to significantly more time spent exposed to the sun with often reduced clothing protection. The potential increased risk of related health conditions, such as skin cancer, is significant for many sports at both the winter and summer Olympics. Most sports that require significant sun exposure adopt protection methods. You will often see skiers, cricketers and marathon runners with significant sun protection creams on them during competition, while many items of clothing an athlete uses will address the problem of sunlight exposure.

However, it is not possible to apply single strategies that are appropriate across the board, and athletes will need to adopt ones that provide enough protection for their sport both during their training and competition.

A key and substantive study into sun exposure and sport resulted in some important conclusions. Firstly, the issue of sun protection should be one of habit for all athletes in all sports when it is required throughout their training and competitions, just as much as suitable footwear or warming up. Another conclusion was that the provision and support of organising bodies in the area of sun protection was varied, with some providing significant facilities to help athletes be adequately protected, while others left it firmly in the realm of the athletes to take care of. The report recommended that sun protection should be written into the safety codes and practices of sports in the same way as other protective equipment is, such as mouth guards, and that organisers should make sure that provisions are given significant status. This is not just to protect the athletes, but also to change the habits of all participants in that sport. The clothing and protection habits of top class athletes are quickly adapted by participants at all levels, including sun protection in many sports such as cricket. Increasing the profile of protecting against the sun among athletes will enhance the use of protection through all levels of sport.

The nature of the Olympics makes it ideally placed to enhance these goals, as it covers many sports that are broadcast to billions around the world. Statutory requirements on sports organisers to make sure adequate sun protection provisions are in place could make a big difference in improving protection against increased sun exposure during sport. 


R. Harris

Bsc Physical Education, Sports Science and Physics, Loughborough University Founder

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