1. Theories of sleep Restoration (Oswald; Horne) The function of sleep is to allow body to be repaired and restored Oswald (1980) – REM for brain; SWS for body Horne (1988) – core sleep (REM & SWS) vs. optional sleep psychlotron.org.uk

2. Restoration theory Main predictions: Deficits in functioning during sleep deprivation Rebound following deprivation Increase in REM during brain growth, reorganisation & repair Increase in SWS during illness, recovery from injury psychlotron.org.uk

3. Effects of sleep deprivation Animal studies tend to support restoration Prolonged sleep deprivation causes immune failure & death Studies of humans produce less clear-cut results Confounding effects of stress etc. psychlotron.org.uk

4. Rebound Generally, people catch up on sleep following deprivation Not all lost sleep is reclaimed About 70% of lost SWS and about 50% of lost REM typically recovered Only some sleep is necessary psychlotron.org.uk

5. Growth & reorganisation Reduction in sleep over lifespan Highest in infants; highest REM in early years Some changes in adolescence REM NREM 24 hour period Age 5yrs psychlotron.org.uk

6. Illness & injury Sleep does increase during illness and recovery from injury Total sleep time increases during illness REM increases during recovery from brain injury, ECT & drug withdrawal SWS deprivation can cause physical symptoms psychlotron.org.uk

7. Evaluation Much evidence is consistent with the restoration view Main problem comes from apparent lack of serious biological malfunction during sleep deprivation in humans psychlotron.org.uk