Technique
Sleeping on cool hard floor even on hot nights is suboptimal.
It leads to some phlegm accumulation in lungs.
Body is stiffer than when sleeping on a soft bed.
Importance
Some aspects of memory consolidation only happen with more than six hours of sleep.
Teenagers who stay up late on school nights and make up for it by sleeping late on weekends are more likely to perform poorly in the classroom. This is because, on weekends, they are waking up at a time that is later than their internal body clock expects. [Ref]
By depriving rats of sleep for 72 hours, the researchers found that those animals consequently had increased amounts of the stress hormone corticosterone, and produced significantly fewer new brain cells in the hippocampus. [Ref]
Sleep debt
Sleep debt can be repaid, though it won’t happen in one extended snooze marathon. Tacking on an extra hour or two of sleep a night is the way to catch up. [Ref]