The start of hockey seasons is usually a time when playing conditions are affected by hotter weather conditions than in the middle and later part of the season. When playing in these hotter conditions it is critical that hockey administrators, coaches and players utilize all available measures to prevent heat stress conditions which can be detrimental to a player’s health. Such overheating conditions also will affect a player’s performance.
Heat stress causes the body’s core temperature to rise. A series of disorders can develop, ranging from discomfort and pain (heat rash and heat cramps) to life-threatening conditions (heat exhaustion and heat stroke).
The human body functions best within a narrow range of internal temperature. This core temperature varies from 36°C to 38°C. To get rid of excess heat, the body uses two cooling mechanisms:
- The heart rate increases to move blood — and heat — from heart, lungs, and other vital organs to the skin.
- Sweating increases to help cool blood and body. Sweating is the most important way the body gets rid of excess heat.
When too much sweat is lost through heavy labour or working under hot, humid conditions, the body doesn’t have enough water left to cool itself. The result is dehydration. Core temperature rises above 38°C. A series of heat-related illnesses, or heat stress disorders, can then develop.
Even low levels of dehydration have physiological consequences. A loss of 2% body weight causes an increase in perceived effort and is claimed to reduce performance by 10-20% A fluid loss exceeding 3-5% bodyweight reduces aerobic exercise performance noticeably and impairs reaction time, judgment, concentration and decision making – vital elements in all sports.
Just how serious is the effect of heat stress related conditions? In a recent website blog² by Dan Peterson titled ‘Heat Stroke Deaths in Football ‘All Preventable’ a first-year Kentucky high school football coach David Jason Stinson pleaded not guilty to charges of reckless homicide in the death of Max Gilpin, a 15-year-old offensive lineman. Gilpin collapsed Aug. 20 while running sprints with the team on a day when the heat index reached 94 degrees.
The case could signal a landmark shift in the expectation for how coaches deal with struggling players on a hot day. Gilpin’s body temperature was 107 degrees when he reached the hospital and he died three days later from heat stroke. The risks of heat-related diseases to athletes, both young and old, are always present but the warning signs are often hidden.
Since 1995, 33 football players have died from heat stroke, according to an annual report from the University of North Carolina. Frederick O. Mueller, professor of exercise and sports science at UNC and the author of the report, calls the figure unacceptable.
“There’s no excuse for any number of heat stroke deaths, since they are all preventable with the proper precautions,” Mueller said.
The wake-up call has been delivered to all coaches. They must be able to recognize a struggling player and resist the assumption that they’re just being lazy. Dave Stengel, the prosecuting attorney in the Stinson case, described the coach’s responsibility: “This is not about football. This is not about coaches,” he said. “It’s about a trained adult who was in charge of the health and welfare of a child.”
Heat stroke is the most serious of the four levels of heat stress. Progressing from dehydration to heat cramps to heat exhaustion without intervention may lead to heat stroke where the core body temperature exceeds 104 degrees.
Since the common symptoms (nausea, incoherence, fatigue, weakness, vomiting, muscle cramps) of heat exhaustion and heat stroke are similar, it can be hard to tell when a player has crossed that dangerous line.
That is why most medical professionals recommend a proactive approach to playing in the heat. The following steps can be used to help prevent heat stress conditions;
- Pre-hydration 12-24 hours before exercise, water for exercise less than an hour, sports drinks for exercise more than an hour
- Carbohydrate intake before exercise
- Liquid intake every 10-15 minutes during exercise
Wear clothing which allows heat to radiate - Avoid extreme weather conditions
- Utilize special cooling garments like Arctic Heat products
- Slow acclimation to the heat over several days, planned and regular water breaks, reduced activity is essential strategies.
The symptoms of heat exhaustion and heat stroke
Sports Medicine Australia has a risk management policy that can assist hockey administrators and coaches in planning to prevent heat stress conditions. Go Hockey news has done a product review on Arctic Heat cooling products to coincide with this blog.
References:
² http://www.livescience.com/5286-heat-stroke-deaths-football-preventable.html
