Karoshi

Karoshi

The Japanese have a name for death through overwork, karoshi. The expression that "nobody ever died from hard work" is simply not true. The recent death of a Bank of America intern from an epileptic seizure could have been triggered by fatigue or sleep deprivation, Poplar's Coroner's Court heard:
 http://www.theguardian.com/business/2013/nov/22/bank-intern-moritz-erhardt-died-epileptic-seizure-shower 

There have been case reports of epileptic seizures triggered only by sleep deprivation. Sleep deprivation seems to have an effect on interictal epileptiform discharges (IEDs). Sleep deprivation will only trigger seizures in susceptible individuals, but those individuals will often have no reason to suspect that susceptibility.

Guinness World Records no longer accept record attempts for sleep deprivation over health concerns. The extreme sleep deprivation experiments in rats are marred by the methodology which imposed severe stress, which may well have been the cause of death. 

Severe stress from overwork can result in raised cortisol levels, raised blood pressure, heart attacks and strokes. The first reported case of Karoshi was a stroke in a 29 year old in 1969. It seems like it's not hard work as such that's the problem, but the associated stress, fatigue and sleep deprivation.