Ready, Set, Hot!: Does Warm Weather Play a Role in Football Concussions?
San Diego, CA (April 28, 2014) — A loss of just two percent of the body’s water volume to dehydration—a feat easily achieved during prolonged exercise in hot weather—can lead to a significant reduction in the amount of cerebrospinal (CSF) fluid that a person has. CSF acts as a cushion to protect the brain from hitting against the inside of the skull during jarring movements. For football players, games conducted in hot and humid conditions could present the perfect storm of risk factors to up their chances for a concussion.
Researchers at the University of Windsor investigated whether the incidence of concussion increased along with the temperature. J. Craig Harwood will present the research team’s findings in a poster session on Monday, April 28, at the Experimental Biology Meeting (San Diego Convention Center from 12:45–3:00 PM PST).
Harwood et al. compiled data on 420 NCAA FBS game-time concussions that occurred during games played outside over a five year period (2008-2012). They also looked at environmental conditions (temperature, humidity, and wind speed) during those games.
From the authors: “The relationship between hydration status and injury occurrence, such as skeletal muscle cramps, is well known, but more information is needed regarding physiological status and the risk of more severe injury like concussion. We were initially interested in the link between dehydration and concussion frequency/severity, however this type of observation was obviously problematic (e.g., measuring game time hydration status in thousands of athletes prior to head injury). Hydration status was unknown, and factors like helmet function (which is compromised in cold conditions) may hide true differences.
We hypothesized that if a relationship existed, we would be able to observe an increase in concussion frequency during games that took place under extreme conditions. But given the primary playing season (i.e., Fall), very few games were played in environmental extremes. Additionally, the high level of competition likely insured that athletes were well prepared for games in all conditions. In the end, the overall rates of concussions were consistent across game time temperatures, but a link between dehydration and concussion rate may still exist.
Game time environmental conditions and concussion rate in college football
A central function of cerebrospinal fluid (CSF) is to limit brain impact against the bony interior surface of the skull during jarring movements. Dehydration of approximately 2% of total body volume can reduce CSF volume by 10%. In prolonged competition, especially in hot, humid conditions, athletes commonly reach or exceed this level of dehydration, potentially reducing the brain’s natural cushioning system and increasing the susceptibility to impact concussion injury. Moreover, protective athletic equipment may lose its effectiveness in the extremes of heat or cold. It is unknown, however, whether the frequency of concussion is impacted by typical environmental conditions experienced during the college football season. Consequently, the aim of the present study was to observe the relationship between game time environmental conditions and the incidence of reported concussion during Football Bowl Subdivision (FBS) NCAA football games. METHODS: Reported concussions (420) during competition and game time (i.e. within 30 min of game start) temperature (T), humidity (H) and wind speed (WS) were collected from publicly available data for 3645 FBS NCAA football games for the 5 year period 2008-2012. Indoor (dome) games (82 games, 8 concussions) and games for which hourly weather data could not be found (106 games, 8 concussions) were not included in the analysis. Environmental conditions were binned prior to frequency analysis. RESULTS: Game concussion frequency was not significantly related to T, H or WS and not related to environmental extremes (i.e. heat index or wind chill). CONCLUSION: Environmental conditions do not impact concussion frequency in college football.
NOTE TO JOURNALISTS: To schedule an interview with a member of the research team, please contact Stacy Brooks at email@example.com or (240) 432-9697.
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