Transcontinental Race No. 6 - TCR6 - #TCRN06 - 2018

Definitely possible. From Wikipedia:

• 1991, Andy Warhol: Five years after his death, Warhol's family publicly accused the hospital where he had his gallbladder removed of causing his death by water intoxication administered post-operatively. A claimed autopsy weight of 150 lbs, with his weight being 128 lbs when admitted, was cited as evidence that too much fluid has been given.
  
• October 24, 1995: Anna Wood, a 15-year-old Australian schoolgirl, died from the effects of water intoxication secondary to use of MDMA (commonly known as Ecstasy).
  
• November 16, 1995: Leah Betts, an English schoolgirl, died as the result of drinking too much water, though in the media her death was mistakenly attributed to taking an ecstasy tablet at her 18th birthday party. [drank 7 litres in 90 minutes]
  
• 2003: British actor Anthony Andrews survived a case of water intoxication. He was performing as Henry Higgins in a revival of the musical My Fair Lady at the time, and consumed up to eight litres of water a day. He was unconscious and in intensive care for three days.
  
• January 12, 2007: Jennifer Strange died after drinking what is believed to be 2 gallons (7.5 liters) of water in an attempt to win a Nintendo Wii. The KDND radio station's morning show, the Morning Rave, held an on-air contest entitled "Hold Your Wee for a Wii," in which contestants were asked to drink as much water as they could without urinating. KDND was subsequently ordered to pay US$16,577,118 in damages to Jennifer's family.
  
  

Obviously he's doing a lot of sweating, but may have overdone it?