Here's the discussion part on long sleep:
> Proposed mechanisms for mortality associated with long sleep include: (I) long sleep is linked to increased sleep fragmentation that is associated with a number of negative health outcomes; (II) long sleep is associated with feelings of fatigue and lethargy that may decrease resistance to stress and disease; (III) changes in cytokine levels associated with long sleep increase mortality risk; (IV) long sleepers experience a shorter photoperiod that could increase the risk of death in mammalian species; (V) a lack of physiological challenge with long sleep decrease longevity; (VI) underlying disease processes mediate the relationship between long sleep and mortality.