Based on the rampant claims of things like chronic fatigue syndrome, fibromyalga, lower back problems, hives, chronic pain, etc, etc. I think there's got to be something tremendously unhealthy about the lifestyle. There seems to be a disproportionately great number of psychologically influenced conditions among JWs. At least in my area, but it seems that this isn't limited to one place based on what I've read on the forum.
Adding in things like excessive drinking, overeating, etc that people also do when dealing with mental stress and you start to see why so many JWs have things like gout, diabetes, and heart problems too. All likely caused by either the "can never do enough" lifestyle or repressing inner thoughts/doubts.