Being sick, as I have been for the last few days, forces upon oneself the reality of the body. A cold, is all it takes to drive home the wisdom of the second remembrance:
I am of the nature to have ill health.
I cannot escape having ill health.
Head cluttered with fever, chest shaken with a relentless cough, limbs burdened with soreness, there is no room left for extra-thoughts. The mind can only attend to the present moment, the unpleasantness of sick body. Of course, the temptation is great to want to jump to aversion, 'I hate this', and its cousin, craving for the return to a healthy state, 'I want to be well'.
Being sick, one gets to practice mindfulness of vedana, using the bridge from the second remembrance to get one step closer to equanimity and acceptance of the inherently displeasing nature of this life.
Being sick, is a dress rehearsal for what it must be like at the time of final parting:
I am of the nature to die.
There is no way to escape death.
Lots of one's fears about death are born out of times when the body is well enough to leave the mind free to make up stories about one's dying. Just a cold is enough to make one realize what happens when the body breaks down. The illness takes over, and the unpleasantness is such that one becomes disenchanted with life. Letting go starts feeling sweet.