Sleepiness and Sleep
While we may not often think about why we sleep, most of us acknowledge at some level that sleep makes us feel better. We feel more alert, more energetic, happier, and are able to function better following a good night of sleep. The function of sleep can be compared to other life-sustaining activities
Theories of Why We Sleep
Survival function by keeping organisms out of harm’s way at times when they would be particularly vulnerable.
Energy Conservation Theory:
The primary function of sleep is to reduce an individual’s energy demand and expenditure during part of the day or night, especially at times when it is least efficient to search for food
Another explanation for why we sleep is based on the long-held belief that sleep in some way serves to “restore” what is lost in the body while we are awake. Sleep provides an opportunity for the body to repair and rejuvenate itself. Other rejuvenating aspects of sleep are specific to the brain and cognitive function.
Brain Plasticity Theory:
One of the most recent and compelling explanations for why we sleep is based on findings that sleep is correlated to changes in the structure and organization of the brain. This phenomenon is known as brain plasticity.
Sleep requirement varies with age.
|Sleep Requirement Varies With Age|
|Newborn (0-2 months)||12 to 18 hours|
|Infants (3-11 months)||14 to 15 hours|
|Toddlers (1-3 years)||12 to 14 hours|
|Preschoolers (3-5 years)||11 to 13 hours|
|School-age children (5-10 years)||10 to 11 hours|
|Teens (10-17 years)||8.5 to 9.25 hours|
|Adults||7 to 9 hours|