Summer Safety: Preventing Heat Illness

Heat illness is a broad term that encompasses several conditions, ranging from mild heat cramps to heat stroke. Heat illness is typically caused by a combination of hot environment, strenuous exercise, inadequate adaptation to the heat, age, hydration levels and/or a poor choice of clothing. It’s always a risk in summer sports, particularly football and running.

Many factors can contribute to a person experiencing heat illness:

Acclimation/Environment: The increase in outside temperatures in spring can be problematic for many athletes if they don’t get the opportunity ease into the change. Acclimatization is the process of becoming adjusted to your environment gradually over time. If athletes in training are pushed too hard too fast, there is an increase risk that they will experience some form of heat illness.

Fitness Level/Adaptation: In order to cool the body the heart needs to pump harder to get the blood to flow out to the skin. If you are overweight or have a low fitness level, extreme heat can be an added strain on the cardiovascular system even without adding exercise into the mix. So if you decide to start training in the spring and summer, allow your body ample time to adapt to the exercise as well as the changing conditions.

Age: As we age, we do not adjust as well to sudden changes in temperature. Elderly people are also more likely to have a chronic medical condition that changes the normal body responses to heat or medication that alters their body’s ability to adapt to extreme heat. Older adults can protect themselves from heat illness by avoiding strenuous exercise during the hottest parts of the day, seeking air-conditioned environments, or taking a cool shower or bath.

Dehydration: On average, we lose about three litres of water each day through perspiration, urine and respiration. When you add a workout in on a hot day, you can quickly see how replenishing your body’s water becomes even more necessary. Even mild levels of dehydration (3-5% of body weight) can hurt athletic performance. How do you know if you are drinking enough? A good sign of hydration is the output of large volumes of clear, dilute urine.

Clothing: Loose, lightweight material allows for better air circulation and facilitates evaporation of sweat. Clothing should be lightweight, light-coloured, and loose-fitting such as cotton or a wicking fabric; avoid dark, non-breathing synthetic clothing.

Symptoms of heat stress may include:

• normal or elevated body temperature 
• body rash 
• profuse sweating 
• fast, shallow breathing and/or a fast, weak pulse 
• heat cramps, nausea, vomiting, or diarrhea 
• exhaustion, headache, dizziness, weakness, or fainting 

Heat injury is preventable and prevention begins with understanding the causes of heat illness. Knowing the signs of heat injury will reduce the number of potential injuries and allow you to train and exercise safely during the summer.

References from the SIRC Collection:

1. Crandall C, González-Alonso J. Cardiovascular function in the heat-stressed human. Acta Physiologica. August 2010;199(4):407-423. 
2. Johnson E, Kolkhorst F, Richburg A, Schmitz A, Martinez J, Armstrong L. Specific Exercise Heat Stress Protocol for a Triathlete's Return from Exertional Heat Stroke. Current Sports Medicine Reports (Lippincott Williams & Wilkins). March 2013;12(2):106-109. 
3. LAROSE J, WRIGHT H, SIGAL R, BOULAY P, HARDCASTLE S, KENNY G. Do Older Females Store More Heat than Younger Females during Exercise in the Heat?. Medicine & Science In Sports & Exercise. December 2013;45(12):2265-2276. 
4. Roberts W. Heat stress and athletic participation. International Sportmed Journal. June 2008;9(2):67-73. Schlader Z, Stannard S, Mündel T. Exercise and heat stress: performance, fatigue and exhaustion—a hot topic. British Journal Of Sports Medicine. January 2011;45(1):3-5. 
5. Tsukasa I, Naoyuki H. Effects of Heat Stress on Ocular Blood Flow during Exhaustive Exercise. Journal Of Sports Science & Medicine. March 2014;13(1):172-179. 
6. YAMAZAKI F. Importance of Heat Acclimation in the Prevention of Heat Illness during Sports Activity and Work. Advances In Exercise & Sports Physiology. November 2012;18(3):53-59.

Environmental factors in exercise and sports performance

Preparing for competition requires physical and mental training, proper nutrition, and recovery. It is also essential to understand your competition and how each athlete fits within the team dynamics. These factors, for the most part, are all factors that can be controlled. Then there are factors such as the temperature, allergens, pollution and altitude that cannot be controlled and can have serious effects on human performance.

Environmental factors such as temperature during competition can hinder performance if not taken seriously. The average body temperature is 37°C (98.6°F). In cool and warm weather, wearing the appropriate gear to be able to perform at a high level is necessary. For example, when playing soccer during the month of November in Canada, there is a good chance it will be cold. To reduce the risk of injury and poor performance, athletes have to do a proper warm up, wear the appropriate clothing and stay properly hydrated. In very hot and or humid temperatures, hydrating becomes extremely important. For athletes, cooling off using wet sponges, and wearing breathable clothing can minimize overheating.

Athletes with allergies or those who have respiratory issues can see a decrease in performance due to environmental factors such as high pollen count or poor air quality. Understanding the air quality and pollen count of the competition and training venues is important as this can enable athletes to limit their exposure by training when the counts are low, or taking the proper precautions during mandatory field times.

High altitude can create disadvantages for athletes who are not acclimatized to the higher elevation. For endurance athletes, high altitude can create limitations to training due to their inability to train as intensely as they would at sea level. At such high elevations, the air is thinner, meaning that there is less oxygen. There is also the likelihood of loss of appetite, which could lead to weight loss and compromised recovery times.

Environmental factors, if not anticipated, can give rise to:

• Dehydration, heat stroke, hyperthermia and frostbite due to changes in temperature 
• Difficulty breathing in places with high pollen counts and poor air quality.
• Altitude sickness, weight loss, loss of appetite at high altitude.

Regardless of the environmental factors, and unless told otherwise, most athletes will train and compete under most conditions. One factor to help mitigate poor performance is acclimatization. Getting your athletes used to the environmental conditions they will compete in can be advantageous since they can adapt to the conditions and as such, these conditions will not be a surprise to the athletes. Both the player and coaching staff have to understand and prepare for the adverse environmental factors that might hinder an athlete’s ability to perform at peak shape. Having a proper plan to anticipate environmental conditions is an advantage to the athletes and team performance. Though many environmental factors cannot be controlled, doing your homework beforehand can help limit the potentially negative effect on performance. Having proper equipment and gear, acclimatizing to the conditions by training in comparable conditions, and understanding how the environment will effect the athletes provide a crucial advantage to athletes hoping to compete at their best.

References from the SIRC Collection:

1. Borresen J. Environmental considerations for athletic performance at the 2008 Beijing Olympic Games. International Sportmed Journal. June 2008;9(2):44-55. 
2.  Igor R, Vladimir I, Milos M, Goran B. New tendencies in the application of altitude training in sport preparation. Journal Of Physical Education & Sport / Citius Altius Fortius. June 2011;11(2):200-204. 
3. Lane A, Terry P, Stevens M, Barney S, Dinsdale S. Mood responses to athletic performance in extreme environments. Journal Of Sports Sciences. October 2004;22(10):886-897. 
4. Nimmo M. The application of research to athletic performance in the cold. International Sportmed Journal. December 2005;6(4):224-235. 
5. Moss D. Training & Competing in Smoggy Conditions. Tricks Of The Trade For Middle Distance, Distance & Cross-Country Running. June 2004;:71-75. 
6. Rundell K. Effect of air pollution on athlete health and performance. British Journal Of Sports Medicine. May 2012;46(6):407-412. 7. 
Singh R. Hydration strategies for exercise performance in hot environment. British Journal Of Sports Medicine. September 2, 2010;44:i40. 
8. Wilber R. Current trends in altitude training. / Les tendances actuelles de l'entrainement en altitude. Sports Medicine. 2001;31(4):249-265.

Altitude Training

Training at high altitude has long been used by Olympians as a means of improving their potential.  We all know that athletes always seek to get a competitive edge but what does altitude training really do for an athlete?

Benefits of Altitude Training

For any type of exercise that lasts longer than a few minutes the body needs to use oxygen to the produce energy required for the specific exercise; without oxygen your muscles seize up and have the potential to be damaged.  The theory behind altitude training is that it increases the number of red blood cells in the body which in turn improves the oxygen flow to the muscles, so upon a return to sea level, the increased oxygen could be used to enhance performance.

• Elevated breathing that athletes experience when they return to sea level can account for 10-20% of the body's increase in its ability to consume oxygen
• Oxygen increase can last up to seven days in low altitude

Potential Problems

Acclimatization to a high altitude is not simple and some of these effects could potentially cancel out any possible benefits:

• Weight loss 
• Possibility of immune system being compromised resulting in sickness
• Intense exercise is not possible because of the lack of oxygen
• Some people just do not adapt as well as others
• Accessibility may be too much of a hassle or unrealistic for some athletes

Studies on altitude training have been ambiguous so far and have many debating the pros and cons.  There is not one workout program that is appropriate for everyone, just like at sea level.  In the end it's ultimately up to the athlete and coach to research and decide if it's worthwhile.

References from the SIRC Collection:

1. BLISS D. THE HEIGHTS OF SUCCESS. Athletics Weekly (Descartes Publishing Ltd.). June 2, 2011;66(22):28-30.
2. Hahn A, Gore C. The effect of altitude on cycling performance: a challenge to traditional concepts. / Effet de l'altitude sur la performance cycliste: un defi pour les concepts trraditionnels. Sports Medicine. 2001;31(7):533-557.
3. LOFTUS-HILLS T. THE HIGHS AND LOWS OF ALTITUDE TRAINING!. Australian Triathlete. March 2010;17(5):50-52.
4. Nummela A, Rusko H. Acclimatization to altitude and normoxic training improve 400-m running performance at sea level. / L ' acclimatation a l ' altitude et l ' entrainement "normoxique" ameliorent les performances sur 400 m au niveau de la mer. Journal Of Sports Sciences. June 2000;18(6):411-419.
5. Rusko H, Tikkanen H, Peltonen J. Altitude and endurance training. Journal Of Sports Sciences. October 2004;22(10):928-945.