The Sweet Kiss of Death
As track officials came to greet Hayes and his champion horse, the jockey slid off the horse and into the dirt. Hayes had died sometime during the race, most likely of a heart attack, yet his body had somehow remained in the saddle throughout all the jumps.
Source: Reddit
It was speculated that his death was caused by the rapid weight loss and the sheer excitement combined. Hayes remains the only jockey to ever win a race while dead. As for Sweet Kiss, he never raced again as no jockey was brave enough to ride the horse that was eventually dubbed “The Sweet Kiss of Death.”