...you have a heart attack, are admitted to hospital for almost a week, and are back at work a day or two later.
My office's IT consultant, who's in his early 30s (and not overweight, and not a smoker), was with another client last week when he began experiencing shooting pains down his left arm and tightness in his chest. Luckily, that client happened to be a doctor's office and he was able to receive immediate treatment. He actually looked pretty good today.
Still, I think if it were me, I might take a little time off.