Sleep is an essential part of our lives. Our bodies collapse with fatigue unless we sleep enough hours every day. Some people are like camels -- they can sleep very little for 6 days and then sleep for 24 hours on the last day, others need to have their sleep spread equally over all days of the week. It's also known that with age, our sleep patterns change. The question everybody asks is: How much sleep is enough?.
By Stas Bekman.
Many people don't assess how much sleep they need to function at their best; they just know they don't get enough. Each person's sleep requirement is different. Some people find that they only need 5-6 hours of sleep, while others need 10-11 hours for optimal performance. The average adult functions best with 7-8 hours of sleep a night; however, it is important to consider how much sleep you need on an individual basis.
The number of hours needed to sleep is a matter of "circadian rhythm," or the biological clock function which regulates our sleep-wake cycles.
Humans are evolved to be "diurnal" creatures, as opposed to nocturnal, that is we are hard-wired to operate optimally in the daytime; sleeping at night.
As newborns, we are essentially neither diurnal or nocturnal, having sleep-wake cycles which are frequent and evenly spaced during any 24-hour period; sleeping for 3-4 hours, waking for 1-2 hours, around the clock.
During the first year, this pattern progresses toward consolidation of the sleep period, trending toward increased nocturnal sleep and daytime wakefulness. At one year the infant typically sleeps about 10 hours from around 7 pm until about 5 am, with a couple of naps in the early and late afternoon, respectively.
By age 4-5, the child has lengthened the nocturnal period to about 11-12 hours with one nap in the afternoon.
At age 10, time of sleep onset is somewhat delayed to 8 or 9 pm, and sleep lasts until 6 or 7 am; the nap disappearing.
For most adults, 7 to 8 hours a night appears to be the best amount of sleep, although the amount ranges from 5 hours to 10 hours of sleep each day depending on the individual. It should be noted that a recent research study conducted by Boston University School of Medicine found that study participants that reported sleeping less than 6 hours or more than 9 hours a day had an increased incidence of diabetes, compared to those who slept 7-8 hours
Senior adults were long considered to have further shortened sleep requirements, but it is now thought that this is only because they tend to get less sleep due to increasing intrinsic sleep disturbance, such as sleep apnea, or musculoskeletal pain, which may interrupt or truncate the sleep interval.
The need to nap is not a clear-cut issue, as some cultures agree that a "siesta" in the afternoon is "natural," and people of all ages in those cultures normally take a mid-day snooze.
Sleep lab data suggest strongly that if adults get 8.1 hours of undisturbed sleep in a 24 hour day, that a nap will not be needed. This varies based upon the quality of sleep obtained, and other factors such as state of general health, levels of stress, or fatigue due to prolonged exertion.
Here are some ideas about personal preferences from posts on the sleep-related forums.
"On a work night I sleep 7-8 hours. In the holidays or at the weekend, I sleep about 9 hours. I also have a nap every day after work! I need to nap when I feel tired, sometimes 1-2 times a day. I think it may just be a bad habit, though. 7-8 hours definitely isn't enough for me."
"About 8 is my ideal, but I rarely get it. Being a carer I am often woken several times a night by my mother. As it can take a long time for me to get back to sleep and only a short while before I am called again. I get very irritable when it gets to 4-5 hrs sleep. However when I am alone and get my 8 hrs - I soon rebound and feel good and well balanced. In winter it would be more with dark mornings and less in summer when it is a bright sunny morning."
"You should not always follow the '8 hour rule'. It does not apply to everyone. Remember everyone's body chemistry is different. The important thing is if you're tired the whole day after even 8 hours of sleep. This means that you need more. If you feel fine with 6 hours of sleep and you're fresh everyday, you're fine."
"I get about 5 - 6 hrs a night and find it takes ages to get to sleep - I definitely need more and when on holiday or without children and left to sleep until I naturally wake I seem to have 9-10 hours. I have always needed a lot of sleep but have not got enough for years now. I could nap every afternoon but often don't get the chance. If it gets really bad with many nights of little sleep and no afternoon nap for a week or so then I am literally tearful with needing sleep. I can drop off in minutes in the day if I lie down but it takes hours at night sometimes."
"I used to thrive on 6 hours a night of sleep, now I need 9! That's been since having a child. I don't feel like I've ever gotten over those first couple of years of sleepless nights (breastfeeding on demand too, to a gal with a hearty appetite!) I'd dearly love to get back to thriving on fewer hours a night. I dream so much too - every morning I can remember at least 3 different dreams; so sometimes I feel as if I have never slept."
"Sleep is a real problem for me. Very often I only get about four hours and I'm doing well if I get 6 off and on. I'd love to be able to get 8 hours, preferably unbroken, just to see what it's like! I'm reluctant to take sleeping tablets although I have done from time to time. I've tried the usual alternative therapies but they don't seem to work either. The problem is waking up frequently and/or too early. I'm not expecting any of you to have a magic answer but I do feel that I'm far from being alone and that it's a big problem for many people. I'm convinced that many people in this day and age and for many divers reasons do not get enough sleep and that it could be a contributory factor in a lot of our society's problems."
"I have never slept well. For one reason or another, sleep has always seemed like a grand waste of time. I work out of my home, so going to sleep and waking up has never been an issue. I get maybe 3 to 4 hours of sleep per night. I have never been cranky, never felt tired or un-rested. Some people need sleep, some people don't. If my wife doesn't get her 8 hours, she is a raving bitch (as an example, and it is not reflective of her wonderful nature) Maybe it is genetic, my father never needed to sleep either."
So, as you can see, each person sleeps different hours and they feel different about it. What's important is to find your own sleeping pattern that works for you. If your body demands more sleep you may just have to give it those hours.