Yes, a doctor died from this: Death of Dr. Cynthia Lucero in 2002 Boston Marathon. Apparently there had been debates on this since the late 80s where there were official guidelines in the US promoting drinking water during sports, interestingly coincided with the birth of the US sports drink industry.
I started watching the below video after a discussion with my dad back in my recent return to Malaysia on topics ranging from China to the harm of extreme exercise.