Of these ten, one is death. Contemplation on death and on other forms of sorrow such as old age, and disease, constitutes a convenient starting point for the long line of investigation and meditation that will ultimately lead to Reality. This is exactly what happened in the case of the Buddha. The disinclination to understand death, is no different from the disinclination of a man to subject himself to a medical check-up although he feels that something is wrong with him. We must learn to value the necessity to face facts.
Safety always lies in truth.
The sooner we know our condition the safer are we, for we can then take the steps necessary for our betterment. To live with no thought of death is to live in a fool's paradise. Now that we have understood why such potency attaches itself to reflections on death, let us proceed to engage ourselves in such reflections. Ask him what causes the cessation of the functioning of the human body, he will tell you that the immediate cause is that the heart ceases to beat. Hence, it is disease that ultimately cause the cessation of the heart beat.