People of a certain age are tempted to worry about what is to come, and if the worry becomes too great, they may give whatever ailments may come an earlier power over them than they would otherwise have. Its a phenomenon wonderfully described by John Donne in his "Devotions":
O miserable condition of man! which was not imprinted by God, who, as he is immortal himself, had put a coal, a beam of immortality into us, which we might have blown into a flame, but blew it out by our first sin; we beggared ourselves by hearkening after false riches, and infatuated ourselves by hearkening after false knowledge. So that now, we do not only die, but die upon the rack, die by the torment of sickness; nor that only, but are pre-afflicted, super-afflicted with these jealousies and suspicions and apprehensions of sickness, before we can call it a sickness: we are not sure we are ill; one hand asks the other by the pulse, and our eye asks our own urine how we do. O multiplied misery! we die, and cannot enjoy death, because we die in this torment of sickness; we are tormented with sickness, and cannot stay till the torment come, but pre-apprehensions and presages prophesy those torments which induce that death before either come; and our dissolution is conceived in these first changes, quickened in the sickness itself, and born in death, which bears date from these first changes.Is this the honour which man hath by being a little world, that he hath these earthquakes in himself, sudden shakings; these lightnings, sudden flashes; these thunders, sudden noises; these eclipses, sudden offuscations and darkening of his senses; these blazing stars, sudden fiery exhalations; these rivers of blood, sudden red waters? Is he a world to himself only therefore, that he hath enough in himself, not only to destroy and execute himself, but to presage that execution upon himself; to assist the sickness, to antedate the sickness, to make the sickness the more irremediable by sad apprehensions, and, as if he would make a fire the more vehement by sprinkling water upon the coals, so to wrap a hot fever in cold melancholy, lest the fever alone should not destroy fast enough without this contribution, nor perfect the work (which is destruction) except we joined an artificial sickness of our own melancholy, to our natural, our unnatural fever. O perplexed discomposition, O riddling distemper, O miserable condition of man!