The news stories typically begin in August every year. Athletes, especially football players, are suffering from environmental heat illnesses. Tragically, heat-related deaths have increased over the past 15 to 20 years according to a University of Georgia study. And while we are far ahead of where we were 10 years ago in understanding the dynamics of environmental heat illness (EHI), there is more we can do to increase awareness. As field managers, we have all heard a lot about how hot the surface of artificial turf fields can get under certain conditions, but what does that really mean to the health and safety of the athletes?
On first impression, we gasp at some of the reported surface temperatures on artificial turf fields compared to natural grass. But digging a little deeper into some of the studies that have been conducted on the issue lowers the OMG factor quite a bit. While the infrared thermometer may show the fibers at up to 150 to 180 degrees Fahrenheit on a hot and sunny day with light winds, it doesn’t mean the athletes are playing in a sauna.
Simple observation and at least one study has shown that the hot fibers do not significantly radiate the heat upward, and the net effect on air temperatures at 2 and 5 feet above the surface was 5 degrees or less. While the fibers get really hot, the rubber infill does not heat up nearly as much, nor do the ground temperatures below the field. A 2012 study at Penn State did not reveal any practical differences in surface temperatures when comparing different fiber colors and different infill material, citing “Reductions of 5 or even 10 degrees offer little advantage when temperatures still exceed 150 degrees Fahrenheit.”
So these fields can get hot on the surface. And while it seems that these high temperatures do not translate to a significantly hotter environment for the athlete, a stove-hot playing surface can cause other problems for athletes, like burning feet. A 2007 article in Sports Illustrated told the story of six Peruvian soccer players that suffered burns on their feet while playing on artificial turf in the hot sun.
Since skin can be damaged quite quickly at temperatures reported on the surface of some artificial fields, there is concern for athletes that regularly come in contact with the surface beyond just their feet. In addition to potential skin burns, it seems reasonable that hot feet would contribute to an overheated athlete, and there is at least one company selling insulated insoles for athletes that play on hot artificial surfaces. I have also read accounts of new cleats falling apart, as the glue melts from the high temperatures.
When I visit parks with infill fields on hot days, I am concerned for the small children sitting on the sidelines with their parents watching the games. The parents often sit in chairs, but the toddlers naturally crawl around on the hot turf.
The real issue here is the overheated athlete, and the SFM has a role to play in this often unknown threat to them. After all, EHI is preventable. The National Athletic Trainers Association (NATA) has published a well-developed set of guidelines for the summer secondary school athlete to acclimate themselves to excursions in the heat, and many states have adopted them as rules. Still, I believe there is more we can do, especially in monitoring the environment they are playing in, and limiting activity or postponing play when conditions reach accepted unsafe levels.
The armed forces have studied this issue for a long time, and there are standards for workers doing their jobs in hot environments. In general, just measuring ambient air temperature is not the best gauge for risk. Other factors, especially humidity, play a role in creating a risky environment, and the National Weather Service combines temperature and humidity in issuing heat advisories and warnings with the Heat Index.
Further still, OSHA, the armed forces and others use a composite temperature measurement called the Wet Bulb Globe Temperature (WBGT), which was developed in 1956 by the Marines. The WBGT takes into its calculation not only the temperature, but also the humidity, wind and solar radiation. And if you’ve ever been on an artificial infill field taking surface temperatures on a hot day, you know that a passing cloud or a little breeze will quickly drop the surface temperatures.
Advancements in technology have dropped the cost of the instruments that measure WBGT, and you can purchase a good one for under $250. The better ones can be mounted on a tripod and set to the right height on one end of a playing field. Some of them will even emit loud, audible beeps when predetermined thresholds have been exceeded in WBGT, letting the coach and referees know instantly when certain conditions have been met. I have not found any national standards for athletic events using WBGT except in the Georgia High School Activities Association, which passed rules in 2012. They start limiting activity and how much gear the players wear at WBGT=82. When WBGT is between 82 and 92, they limit activity and increase rest periods. Above WBGT=92, they stop athletic activity.
Sports field managers are safety agents for the athletes, and they can help by first raising awareness within their organizations to this important issue. You can work to provide potable water and cooling zones at the fields. Purchase a WBGT meter and start collecting data with it. Educate yourself and your team, and watch out for your turf team members working long hours in hot weather. A great resource to learn about EHI is the Korey Stringer Institute website in partnership with the University of Connecticut at http://ksi.uconn.edu/.
Keep your cool.