Do you derive the same benefits of sleep while just lying still?

If you did not get your normal amount of sleep and later in the day were able to lie down for 30 – 45 minutes without interruption but were unable to actually fall asleep would it be the same, in terms of body mechanics and function, as being able to have had the same 30 – 45 minutes of sleep earlier?

Not saying that you are tossing and turning and worrying during the rest where your mind won’t let you sleep, just that sleep does not come but you do have the quiet, restful time to allow the body to relax. Almost, but not quite a meditative state.