The family of a runner who died at Saturday's Country Music Marathon is asking for privacy, and has not released his name. The 26 year old man collapsed and died at LP Field, right after crossing the half marathon finish line.  A medical team nearby tried to revive him but could not.  Doctors who examined the man have not said what caused his death, or whether the high temperatures played a role. But a spokesman from Elite Racing says he died of sudden cardiac arrest, not heat.  The Tennessean reports the 80 degree temperatures bothered even the most experienced runners, including the women's winner, who vomitted several times at the end of the race.   Channel 4 News reports hospital emergency rooms at Baptist and Vanderbilt were filled with two dozen runners suffering from heat related problems. 
This is not the first time a runner has died at a marathon.  In 2007, An experienced runner collapsed and died during the Chicago Marathon, and 28 year old elite runner Ryan Shay died in New York during the Olympic trials.  Last year three runners died during U.S. marathons. Most of these deaths are attributed to undetected heart problems, that can be aggravated by heat.   According to Runner's World, the biggest and most recent study of marathon deaths was published in December 2007, about six weeks after Ryan Shay's death. It surveyed 685 marathons in North America in the last 30 years. Out of 3.2 million runners, 26 died from a reported cardiac event, a rate of 0.8 deaths per 100,000. Many of these deaths happened in the last mile of the marathon, or just after the finish, causing researchers to recommend that recreational runners should not sprint at the end of a marathon.  A runner's coaching blog called Running Advice and News explains some of the stress placed on a runner's body during a marathon.