Research Review By Kevin Neeld©

Date Posted:

January 2010

Study Title:

Heat Injury in Youth Sport

Authors:

Marshall SW

Author's Affiliations:

Departments of Epidemiology, Exercise and Sport Science, and Orthopedics; University of North Carolina at Chapel Hill, Chapel Hill, NC

Publication Information:

British Journal of Sports Medicine 2010; 44: 8-12.

Background Information:

Heat-related illness refers to a situation where the body generates or absorbs more heat than it can dissipate. This condition has gained much attention over the last decade because it kills a seemingly increasing number of athletes every year.

Making these circumstances infinitely more unfortunate is the fact that heat-related illnesses are entirely preventable. In order to prevent future cases of heat-related illness and its severe consequences, and to protect coaches from inappropriately pushing athletes through unsafe circumstances, it is necessary to fully understand the risk-factors and symptoms of heat-related illness.

The purpose of this paper was to review the literature for information on heat illness and death in young athletes (age 6-18 years old), to identify resources for preventing such illnesses, and to identify related areas that require further research.

Pertinent Results:

  • In autumn 2008, four high school football players died from a heat-related illness in the USA.
  • It is currently unclear whether the belief that children are at an increased risk of heat illness compared to adults because of a higher surface-area-to-volume ratio, lower perspiration rate, and higher metabolic rate is valid.
  • Seventeen times more high school athletes than college athletes in the US are exposed to activity in hot conditions during preseason football camps (1.1 million high school football players vs. 65,000 college players). This excludes private sports camps, which are heavily attended by young athletes over the summer months.
  • As many as 56% of young athletes in summer sports camps are significantly dehydrated. Actual hydration levels do not correlate with education regarding the importance of adequate hydration, possibly because youth coaches do not allow adequate breaks for hydration.
  • Between 1995 and 2008, 39 football players died from heat stroke (29 high school, 7 college, 2 professional, and 1 “sandlot”).
  • High School football players experience non-fatal heat illness at a rate of 5 per 100,000 athlete-exposures, 11 times higher than every other sport combined. It is likely that the actual number is much higher since athletes can recover from more mild forms of heat-illness within 24 hours, which wouldn’t meet the requirement of missing one or more days.
  • If/when body temperature reaches 104°F (40°C), organ dysfunction and failure may occur in response to heat-related cellular dysfunction.
  • Immersion in ice-cold water appears to be the best immediate remedy to heat-related illness. Heat-related illness is reversible, given that the internal body temperature does not elevate over the 104°F threshold and that the internal body temperature is not elevated above normal for excessively long periods of time.
  • Symptoms of heat injury include: nausea, incoherence, fatigue, weakness, vomiting, cramps, a weak rapid pulse, flushed appearance, visual disturbances, unsteadiness and collapsing.
  • Sports drinks with electrolytes are the preferred means of prevention-based hydration, as these drinks will help prevent hyponatraemia and may be more enjoyable and consequently more heavily consumed.

Clinical Application & Conclusions:

When considering the unnecessarily high rate of heat-related illness during pre-season football camps, it is hard to not picture the uninformed football coach encouraging his players to push themselves past their limits in abnormally hot conditions. It seems to be common practice for many youth programs to attempt to get their athletes “whipped into shape” in a one- or two-week camp. One cannot help but wonder if the majority of these injuries could be prevented by scheduled hydration breaks and a less aggressive approach to fitness (lower initial volumes of conditioning).

The first step toward curbing the severe consequences of heat-related illness is building awareness amongst youth athletes and coaches. Once coaches are aware of the risk-factors and prevention methods, they can build scheduled hydration breaks into their practices.

These breaks will serve two functions: replenish lost fluid and electrolytes and provide a break from high-intensity work for the body’s internal temperature to lower toward normal levels.

It is imperative that coaches make an effort to recognize risk-factors and not necessary equate decreased performance with decreased effort. As researchers shed more light on the underlying physiology of heat-related illness, it will be important for initiatives to be taken to relay this information to youth coaches and players.

Study Methods:

This was a narrative literature review. The author performed a Medline search using the keywords “heat illness”, “heat injury”, “child/adolescent”, and “sports and activity”. Only articles published in English were considered for review.

Study Strengths/Weaknesses:

This primary strength of this review was that it pointed out gaping holes in our scientific understanding of heat illness and in the communication of this knowledge to the coaches of high-risk athletes. Further information regarding the current level of education of youth sport coaches regarding this issue will help provide much-needed information on how these injuries can be prevented in the future.

Additional References:

  1. Howe AS. Heat-related illness in athletes. Am J Sports Med 2007; 35: 1384-1395.
  2. Bytomski JR, & Squire DL. Heat illness in children. Curr Sports Med Rep 2003; 2: 320-324.
  3. McDermott BP et al. Acute whole-body cooling for exercise-induced hyperthermia-a systematic review. J Athl Train 2009; 44: 84-93.
  4. Bergerson MF et al. Youth football: heat stress and injury risk. Med Sci Sports Exerc 2005; 37: 1421-1423.