I dunno.. The article said he averaged 80 hours of overtime per MONTH. That's only 20 per week. The average workweek in Asia (according to some quick research ) is about 45 hours per week. That puts him at 65. I work closer to 70-80 per week and while it's hard, I don't think it's killing me.
I'm guessing there were mitigating circumstances.
Don't get me wrong, the Japanese folks I worked with were madmen when it came to working, during busy times I saw them come in at 7-8AM, work untill 10PM, then go out for Karaoke or what-have-you-untill 2AM several nights per week, then take the hourlong train ride home and still be back at work at 8AM... 80 hours per month just doesn't sound excessive.