The UK’s Sleep Council survey of over 2,000 adults and found that half of them didn’t know how much sleep their children should be getting viz 12 hours for a 3 year old, 10 hours for a 6-12 year old, and 9 hours for a teenager.
Whilst 80% of parents recognised the importance of sleep in relation to school performance, many didn’t understand exactly why.
Chris Idzikowski, at the Edinburgh Sleep Centre, says that sleep is essential for good physical, mental, and emotional health and is crucial for memory, learning and growth. “Bad sleeping habits in childhood can lead to long-term sleep problems and have been linked to obesity and heart disease”.
The Sleep Council believes that knowledge of the subject should be taught in schools alongside healthy eating and exercise and have published a guide for parents: “The Good Night Guide for Children”.
And it’s not just children who might be sleep deprived. The Harvard Business Review in October 2009 also reported on the problem in the USA. There the National Sleep Foundation reported in their “2008 Sleep in America Poll” that nearly a third of adults who work at least 30 hours a week have either fallen asleep or become extremely drowsy on the job.
Earlier that year a report for the National Academy of Sciences showed that a nap with REM or “dream sleep” improves your ability for creative problem solving and there are several studies that show that sleep boosts memory. For example if you memorise a list of of words then take a nap you will remember more words than if you hadn’t slept.
Robert Stickgold and his colleagues found evidence that important memory processing occurs as you are falling asleep as well as linking ideas and separating the wheat from the chaff. Evidence they say that napping helps you to be more creative.
And when you are tired your visual discrimination skills fade. You need a 30 minute sleep to stop the burnout and 60 to 90 minutes including REM sleep to improve visual discrimination.
Some organisations have introduced napping periods; Google has sound and light-proof sleep pods. Such companies believe that it fits into their flexible working policies and boost productivity for little cost. Perhaps more seriously in New Zealand air traffic controllers on night shifts were more alert and performed better if they had a 40 minute sleep break.
Even micro-naps of just 6 minutes – not including the time it takes to fall asleep, which is 5 minutes if you are really tired – can make a difference.
Perhaps the siesta loving countries have had the right idea all along. There was a public outcry when the Portuguese government tried to ban them a few years ago to improve productivity.
Updated 2 July 2010: A new book by Tony Shwartz and colleagues: “The way we’re working isn’t working” the 4 forgotten needs that energise great performance” includes a section on taking care of your health including sleep. Some interesting facts include:
- Melatonin is produced mainly between 1100 and 0300 so working during those times reduces our cognitive ability
- Research at Stanford University shows that extending sleep improves performance
- Chronically sleep deprived people are significantly more likely to suffer from heart disease than people who sleep only 6 hours and who in turn are significantly more at risk than people who sleep the necessary 7 hours (General McCrystal allegedly only sleeps 4 hours)
- Sleeping only 6 hours a night for two weeks has the same effect as someone who has been sleep-deprived for 48 hours
Updated 10 August 2010: Several newspapers in the last week reported that the holy grail of sleep had been discovered. Not so said the Times “Quack Quack – we debunk the myth behind the headlines“. The research at the University of Pennsylvania showed that the performance of volunteers who were restricted to 4 hours sleep a night for 5 nights slumped but made up some but not all of the difference when they were allowed to sleep for ten hours on the 6th day. Basically lie-ins don’t make up for sleep loss.
Scare stories last year said lie-ins ie more than 8 hours sleep, doubled your chance of dementia. And on the one hand research at the University of California showed that people who sleep longest are 15% more likely to die early whilst on the other research at Portland State University showed that people who sleep 10 hours a night have a better chance of reaching a hundred.
There seems to be no optimum length of sleep – it seems a very individual thing. If you stay alert during the day you are probably getting enough.
Updated 20 September 2010: But now experts are saying that if babies and pre-school children don’t get 10 hours of sleep a night they are likely to be overweight when they get older.
A lack of sleep may cause an imbalance in appetite controlling hormones making those short of sleep to feel hungrier and crave snacks during the day. Previous research has linked sleep deprivation with obesity in adults and teenagers but this research from the USA, published in the Archives of Paediatrics & Adolescent Medicine, covered 1,00 under-5s. Those with less than 10 hours sleep were twice as likely to be overweight 5 years later.
The researchers concluded; ” Insufficient night-time sleep among infants and pre-school age children appears to be a lasting risk factor for subsequent obesity” and ” these findings suggest a critical window prior to age 5 years when night-time sleep may be important for subsequent obesity status”.
Newspapers picked up this story and reporter Sophie Borland included some data from other countries to strengthen the case. For example, researchers in China looked at 5,000 children and found that those who were able to catch up on their sleep at the weekend were less likely to put on weight. And in Canada researchers found that people who didn’t get the optimum 7 – 8 hours sleep were two and a half times more at risk of developing Type 2 diabetes.
Updated 4 March 2011: 10% of us are relying on medication to help us sleep. That’s according to a survey of 40,000 families funded by the Economic & Social Research Council.
Apparently 1 in 8 of us now gets less than 6 hours sleep a night and 60% of us take 30 minutes to drop off with 10% of us using medication three times a week to help us do that.
Experts say sleep is as important to our health as diet or exercise and long-term deprivation will have long-term health risks such as diabetes, obesity, and heart problems. This is because hormones controlling your appetite and blood pressure are affected by sleep patterns.
Rather than using medication to give you drug-induced sleep it is better to look at the environmental and life-style factors in busy modern lives to solve the problem.
Updated 2 May 2011: Finally some firm evidence on how much sleep you really need. Experiments at the Sleep and Chronobiology Laboratory at the University of Pennsylvania divided people into 3 groups. Some slept for 4 hours, some for 6 hours, and some for 8 hours a night over a two-week period.
Every 2 hours during the day the researchers tested their subjects to see how alert they were using the psychomotor vigilance task which requires you to sit in front of a computer screen for 10 minute sessions where you had to press the space bar when randomly timed numbers came up.
The PVT test measures the kind of vigilance needed by pilots, truck drivers and astronauts. and also for staying focussed when reading or attending meetings.
Those who had 8 hours of sleep had hardly any attention lapses over the 14 days of the study. Those who had only 4 or 6 hours got steadily worse as each day passed. By day 6, 25% of the 6 hour sleepers were falling asleep at their computer. By the end of the study the 6 hour sleepers were as impaired as those who had been sleep-deprived for 24 hours.
In real life you have more distractions than in a sleep laboratory: regular coffee, bright lights, interaction with colleagues etc but you will still feel the effects of sleep deprivation after five to seven days.
Some of the people who needed 8 hours felt the impact of a 4 hour sleep immediately while others coped for a few days before deterioration inevitably set in. Some people insist they can manage on 5 hours sleep but the 4 and 6 hour sleepers felt that although they felt sleepy they were unaffected. This wasn’t true but people aren’t good at judging their own sleep needs.
Researchers think that there might be a small percentage of people who, because of their genes, can maintain their performance with less than 5 hours sleep just as there are people who require 9 hours or more.
Source: New York Times April 15 2011
Meanwhile scientists at Northumbria University have been studying “short sleepers”. People like Margaret Thatcher, Da Vinci, Thomas Jefferson and Benjamin Franklin, who were too busy to sleep.
These sleepless elite tend to be more ambitious, outgoing, optimistic and energetic than those who would rather have a lie-in. The scientists think that there are perhaps only 3% of the population who can thrive on less than 6 hours sleep and research is being carried out world-wide to try to identify the gene responsible for this.
The short sleepers are both owls and larks as they often go to bed after midnight but get up before dawn.
The UK researchers believe that Britons are already sacrificing 4 hours sleep a week because of stress and work commitments and risk chronic insomnia and in America about 15% of adults report sleeping less than 6 hours a night.