Why do we sleep?
A lot is still unknown about the purpose of sleep. However, it’s widely accepted that there isn’t just one explanation for why we need to sleep. It’s likely necessary for many biological reasons.
To date, scientists have developed several promising theories to explore the question of why we sleep from many different angles. The most prominent theories and reasons are outlined below.
Inactivity Theory
One of the earliest theories of sleep, suggests that inactivity at night is an adaptation that served a survival function by keeping organisms out of harm’s way at times when they would be particularly vulnerable.
Energy Conservation Theory
The theory suggests that 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.
Restorative Theories
Based on the long-held belief that sleep in some way serves to "restore" what is lost in the body while we are awake during the day.
Brain Plasticity Theory
Based on findings that sleep is correlated to changes in the structure and organization of the brain, especially in memory consolidation, acquisition and recall.
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How does the body regulate sleep?
Have you ever noticed that you feel more alert at certain times of day, and feel more tired at other times? Those patterns are a result of two body systems: sleep/wake homeostasis and circadian rhythm, which determine your sleep drive at any given time.