Speaking for myself, I really believe that my fear of death and questioning of an afterlife has a very strong influence and bearing on choices I am making with regard to my health and quality of life. I haven't yet started a vigorous exercise program and made strict dietary changes, but they're very soon in the works, as well as improving other general areas, such as stress management.
I wish I didn't fear death, the way an Atheist or Christian doesn't fear it. Their beliefs are absolutes. There must be a lot of comfort in that.