One area of higher risk for organizers and participants of community sporting events in tropical locations such as the Singapore Youth Olympic Games 2010 is that of a physical environment of high heat and humidity. These events are more likely to see participants from non-tropical environments push themselves beyond their normal boundaries of activity and both athletes and organizers need to take extra precautions.
At any time, high intensity exercise in a hot environment, with the associated elevation of body temperature, can lead to heat illness. Heat illness in sport presents as heat exhaustion or the more severe heat stroke.
Characterized by a high heart rate, dizziness, headache, loss of endurance/skill/confusion and nausea. The skin may still be cool/sweating, but there will be signs of developing vasoconstriction, e.g pale color.
The rectal temperature may be up to 40°C and an athlete may collapse on stopping activity. Rectal temperature should only be measured by a doctor or nurse.
To avoid heat exhaustion, if you feel unwell during exercise you should immediately cease activity and rest. Further benefit comes if the rest is in a shaded area with some passing breeze (from a fan if necessary) and you take extra hydration. Misting or spraying with water can also help.
Characterized similar to heat exhaustion but with a dry skin, confusion and collapse. Heat stroke may arise in an athlete who has not been identified as suffering from heat exhaustion and has persisted in further activity. Core temperature measured in the rectum is the only reliable diagnosis of a collapsed athlete to determine heat stroke.
Heat stroke is a potentially fatal condition and must be treated immediately. It should be assumed that any collapsed athlete is at danger of heat stroke. The best first aid measures are “Strip/Soak/Fan.”
- Strip off any excess clothing
- Soak with water
- Ice placed in groin and armpits is also helpful
The aim is to reduce body temperature as quickly as possible. The athlete should immediately be referred for treatment by a medical professional.
Important: heat exhaustion/stroke can still occur even in the presence of good hydration.
Dehydration is fluid loss which occurs during exercise, mainly due to perspiration and respiration. It makes an athlete more susceptible to fatigue and muscle cramps. Inadequate fluid replacement, before, during and after exercise will lead to excessive dehydration and may lead to heat exhaustion and heat stroke.
To avoid dehydration, you should drink about 500mls (2 glasses) in the 2 hours prior to exercise. During exercise longer than 60 minutes, 2-3 cups (500-700ml) of cool to lukewarm water or sports drink are sufficient for most sports. After exercise, replenish your fluid deficit to ensure you are fully re-hydrated, but not over-hydrated.
Take note, even a small degree of dehydration will cause a decrease in performance. However be sure not to over-hydrate. Drinking too much fluid can lead to a dangerous condition known as hyponatraemia (low blood sodium). Aim to drink enough to replace lost fluids, but not more than that.
Type of clothing is vital in minimizing health risks associated with exercise in heat. Fabrics that minimize heat storage and enhance sweat evaporation should be selected. Light weight, light colored, loose fitting clothes, made of natural fibers or composite fabrics with high wicking (absorption) properties, that provide for adequate ventilation are recommended as the most appropriate clothing in the heat. This should be applied to the clothing worn by not just athletes, but also umpires, other officials and volunteers.
If clothing is worn for protective reasons, ensure that it is worn only while training and competing in hot weather. Some examples include leathers in motor sports and mountain biking, protective equipment for hockey goalkeepers, and softball umpires.
Remove non-breathable clothing as soon as possible if the athletes or officials are feeling unwell in hot conditions. Start cooling the body immediately via ventilation and/or a cool spray such as a soaker hose or a hand-held spray and a fan.
Acclimatization of Participants
Acclimatization of the participant includes the umpires, other officials and volunteers as well as the athletes.
Preparation for exercise under hot conditions should include a period of acclimatization to those conditions, especially if you are traveling from a cool / temperate climate to compete under hot / humid conditions such as in the case of Singapore.
It has been reported that youth and children acclimatize slower than adults. Regular exercise in hot conditions will facilitate adaptation to help prevent the athlete’s performance deteriorating, or suffering from heat illness during later competitions. 60 minutes acclimatization activity each day for 7-10 days provides substantial preparation for safe exercise in the heat.
Fitness Levels & Athletic Ability of Participants
A number of physical/physiological characteristics of the athlete will influence the capacity to tolerate exercise in the heat, including body size and endurance fitness.
In endurance events an accomplished but non-elite runner, striving to exceed their performance may suffer from heat stress. The potential for heat related illnesses would be exacerbated if they have not acclimatized to the conditions and have failed to hydrate correctly.
Overweight and unconditioned athletes, umpires, officials and volunteers will also generally be susceptible to heat stress.
Age and Gender of Participants
Ladies may suffer more during exercise in the heat, due to their greater percentage of body fat. Young Children are especially at risk in the heat. Prior to puberty, the sweating mechanism, essential for effective cooling, is poorly developed. The ratio between weight and surface area in the child is also such that the body absorbs heat rapidly in hot conditions.
In practical terms, young athletes must be protected from over-exertion in hot climates, especially with intense or endurance exercise.
Although youth can acclimatize to exercise in the heat, they take longer to do so than adults. Coaches should be aware of this and limit training for non-acclimatized youth during exposure to hot environments.
Predisposed Medical Conditions
It is important to know if athletes, umpires, officials or volunteers have a medical condition or are taking medication that may predispose them to heat illness.
Examples of illnesses that will put the participant or official at a high risk of heat illness include: asthma, diabetes, pregnancy, heart conditions and epilepsy. Some medications and conditions may need special allowances.
Participants and officials who present with an illness such as a virus, flu, gastro, or feeling unwell are at an extreme risk of heat illness if exercising in moderate to hot weather.
Participants or officials who may be affected by drugs or alcohol may be at an extreme risk of heat illness if exercising in moderate to hot weather.
Other factors to Consider
Preventative measures can be undertaken to minimize heat injuries. Examples include the provision of shade, hats, appropriate sunscreen, spray bottles and drinking water. It is important to have trained personnel available to manage heat injuries and designated recovery areas for patients. In situations where heat problems may be expected, an experienced medical practitioner should be present.