Sleep needs are probably genetically determined, and can vary between individuals from as little as 4-5 h/day to 9-10 h/day, with an average of 7-8 h/day. How much sleep someone needs cannot be stated simply as a certain number of hours though, since the effectiveness of sleep depends on when the sleep happens. If we sleep at the wrong time of the day, in relation to our biological clock, our sleep will be less effective.
Basically, we consider sleep to be adequate when the person does not suffer from daytime sleepiness or impaired functioning. When sleep is not adequate, they suffer from sleep deprivation.
Total sleep deprivation is very rare – almost everyone gets at least some sleep along the way. Partial sleep deprivation, i.e. when we get less sleep than we need, is quite common in modern society however.
Partial sleep deprivation often becomes a chronic condition, where a person never quite manages to catch up on their sleep debt. Alarmingly too, people who suffer from partial sleep deprivation often misjudge their ability to function, and believe themselves to be more functional than they are.
Effects of sleep deprivation
Sleep deprivation can lead to any combination of effects, such as…
- Microsleeps, where the brain goes into a sleep state for a period of between one second to half a minute. Importantly, this can occur without the person being aware of them happening, and regardless of what activity the person is involved in.
- Severe daytime sleepiness and fatigue, resulting in lower quality of life.
- Mood changes; irritability, lack of motivation, interest and initiative.
- Impairment of judgement, creativity and mental flexibility.
- Cognitive impairment on tasks that require sustained attention and rapid reactions, such as driving a car. Research has shown that people who drive after being awake for 17 to 19 hours perform worse than if they would have a blood alcohol level of .05%, and after 21 hours their performance is equal to having a blood alcohol level of .08%! [ref. 1 & 2]
Even more worrying is research published in 2010 by a research team from the University of Warwick (UK) and the Federico II University medical school in Naples (Italy), covering more than 1.3m people and more than 100,000 deaths.
This team found that those who generally slept for less than six hours a night were 12% more likely to experience a premature death over a period of 25 years than those who consistently got six to eight hours’ sleep. More specifically they found that if you sleep less than six hours per night and have disturbed sleep you stand a 48% greater chance of developing or dying from heart disease and a 15% greater chance of developing or dying from a stroke. [ref. 3]
So, if you suffer from poor sleep, and are chronically sleep deprived, making sure to address this problem is obviously of utmost importance. If you are interested in overcoming sleep problems without the need to take medications, contact me today, or visit the page, Relax-the-Mind Sleep Therapy, to read about a drug-free alternative for conquering insomnia and similar sleep disorders.
- Dawson, D., & Reid, K. (1997). Fatigue, alcohol and performance impairment. Nature, 388 (6639), 235.
- Williamson, A. M., & Feyer, A. M. (2000). Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. Occupational and Environmental Medicine, 57(10), 649–655.
- Cappuccio, F. P., D’Elia, L., Strazzullo, P., & Miller, M. A. (2010). Sleep Duration and All-Cause Mortality: A Systematic Review and Meta-Analysis of Prospective Studies. Sleep, 33(05), 585-592.