Sun undergoes eclipse and clouds sometimes covers the sun, yet after the eclipse and moving of clouds, sun is visible shining like earlier.
Moon too undergoes eclipse and waxing and waning and also covered by clouds, yet once these are over, moon shines like earlier.
Similarly the mind and body undergo changes even though whatever we try to suspend those changes, yet the soul the real us shines like earlier.
At a certain moment, soul leaves the body. Body composed of five elements get absorbed into those elements and soul merges with the source the almighty. For rarest and lucky ones even while having body soul dissolves into the almighty without any activities left for body to do. Such are the videhamuktas.
Having gotten a human birth is really a luck and the primary and ultimate goal is to realise the self and experience the eternal bliss which is always available within us. Rest all is secondary. Deep sleep, reaching the orgasm, enjoying all different types of joy through body etc. are few moments in which one experience the self, the bliss. In meditation one can experience the bliss clearly. Then one will be able to realise the joy is within the self and all the outside objects including body are just helping one to realise this truth.