There are episodes in consciousness during sleep. They are called "dreams". There are also periods in sleep when the mental consciousness is completely still. That is a deeper form of sleep, and it is the form needed to restore full vitality.

The purpose of meditation is to still the mental consciousness while one is still awake.

Ask yourself why, Pied Piper. What would be the purpose in doing that? Have you ever done it? Have you ever tried to do it? Most people never have, therefore they don't know what it's like.