07 - About Sleep

Taken from Pg. 37 in the book:
Sleep is basic human need, as basic as the need for oxygen. Getting a good night's sleep is not the only directly related to how we feel the next day, but to our long-term health as well. Still, many of us suffer from at least occasional insomnia. Even more of us report at leas one night of restless sleep per week that leaves us feeling ill and irritable. This is a serious problem. If you think otherwise, consider this. People who sleep four hours or less per night are twice as likely not to survive in six years as those who sleep the normal eight hours or so.

Investigation:

Sleep is a natural state of bodily rest observed throughout the animal kingdom. It is common to all mammals and birds, and is also seen in many reptiles, amphibians and fish. In humans, other mammals, and a substantial majority of other animals which have been studied such as fish, birds, ants, and fruit-flies. Regular sleep is essential for survival. However, its purposes are only partly clear and are the subject of intense research.

Optimal amount in humans: adults
The optimal amount of sleep is not a meaningful concept unless the timing of that sleep is seen in relation to an individual's circadian rhythms. A person's major sleep episode is relatively inefficient and inadequate when it occurs at the "wrong" time of day. The timing is correct when the following two circadian markers occur after the middle of the sleep episode but before awakening:

1 - Maximum concentration of the hormone melatonin, and
2 - Minimum core body temperature.

The National Sleep Foundation in the United States maintains that eight to nine hours of sleep for adult humans is optimal and that sufficient sleep benefits alertness, memory and problem solving, and overall health, as well as reducing the risk of accidents. A widely publicized 2003 study performed at the University of Pennsylvania School of Medicine demonstrated that cognitive performance declines with fewer than eight hours of sleep.

However, a University of California, San Diego psychiatry study of more than one million adults found that people who live the longest self-report sleeping for six to seven hours each night. Another study of sleep duration and mortality risk in women showed similar results. Other studies show that "sleeping more than 7 to 8 hours per day has been consistently associated with increased mortality", though this study suggests the cause is probably other factors such as depression and socio-economic status which would correlate statistically. It has been suggested that the correlation between lower sleep hours and reduced morbidity only occurs with those who wake after less sleep naturally, rather than those who use an alarm.

Optimal amount in humans: children
Children need a greater amount of sleep per day than adults to develop and function properly: up to 18 hours for newborn babies, with a declining rate as a child ages. A newborn baby spends almost half of its sleep time in REM sleep (REM-Rapid Eye Movement). By the age of five or so, only a bit over two hours are spent in REM.

Amount of sleep for optimal perfomance:
Newborn => Up to 18 hours
1 - 12 months => 14 to 18 hours
1 - 3 years => 12 to 18 hours
3 - 5 years => 11 to 13 hours
5 - 12 years => 9 to 11 hours
Adolescents => 9 to 10 hours
Adults, including elderly => 7 to 8 (or more) hours
Pregnent women => 8 (or more) hours

According to this information, I should sleep 7 to 8 hours. Something almost imposible for me to do most of the time because of my everyday "activities". I'll try to "make up" for lost sleep later although I know it doesn't work that way. Circadian markers don't adjust properly when trying to "make up" for lost sleep, but the idea of "making up" for lost sleep is just a fallacy that renders hope...

fallacy - Erroneous reasoning that has the appearance of soundness.