WHY WE SLEEP
Scientists have proposed the following theories on why humans require sleep:
- Sleep may be a way of recharging the brain. The brain has a chance to shut down and repair neurons and to exercise important neuronal connections that might otherwise deteriorate due to lack of activity.
- Sleep gives the brain an opportunity to reorganise data to help find a solution to problems, process newly learned information and organise and archive memories.
- Sleep lowers a person's metabolic rate and energy consumption.
- The cardiovascular system also gets a break during sleep. Researchers have found that people with normal or high blood pressure experience a 20 to 30% reduction in blood pressure and 10 to 20 % reduction in heart rate.
- During sleep, the body has a chance to replace chemicals and repair muscles ,other tissues and aging or dead cells.
- In children and teenagers , growth hormones are released during deep sleep.
When a person falls asleep and wakes up is largely determined by his or her circadian rhythm ,a day-night cycle of about 24 hours .Circadian rhythms greatly influence the timing, amount and quality of sleep.
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