This theory states that sleep is to allow the body to rest, restore and repair. However, theories debate whether it is the body or the brain that needs to rest.
Believes SWS is useful for the bodies recovery process. During SWS there is a release of the growth hormone from the pituitary gland. This provides support for the theory as as this may stimulate protein synthesis and contribute to repair of body tissue. It is also argues that important recovery process for the brain during REM sleep. Overall, NREM sleep is good for the body, REM is good for the brain.
Simialr to Oswalds theory. Argued humans have periods of using energy during relaxed wakefulness. Repair of body tissue can occur during this rather than sleep. However, central to both is that sleep is essential for survival - Disagreements concern precise mechanisms involved in recovery/restoration. He states that lighter stages of sleep are not required/are optional and that sleep is imporant…