Stress is the silent killer. My wife's uncle died yesterday of a massive heart attack at the young age of 50. Six (3 boys and 3 girls) beautiful children ranging from ages 2 to 17. The most well behaved and respected kids I have ever met. Kills me to think they'll all grow up without their dad. To stand there last night and watch the three little girls hug their daddy and say their goodbyes to him as his deceased body was resting on the hospital bed was probably the one of the most difficult events to witness in my life.
Doesn't have to be this way. The father worked endless hours at DuPont managing stress so his family could have a good life. Unfortunately, his health took a back seat to his career and the nagging from his wife to just slow down never got through.
So I'd say stress management and balancing one's life is one of the main pillars to living a long, healthy life.