Rates of heat-related illnesses, such as heat cramps and heat strokes, were reduced by half in places that follow state-mandated guidelines to reduce exertional heat illness among high school football players, according to a study. The study examined the effectiveness of state-mandated guidelines for reducing exertional heat illness among high school football players and provided compelling evidence that exertional heat illness can be prevented through mandated safety policies. The study findings were published in the Journal of Environmental Health Perspectives. Heat-related illness is a potentially life-threatening injury for high school athletes and is most common among high school football players. Tough physical practices in hot, humid conditions increase the risk of a wide range of exertional heat illness conditions.