How sleep can save your life

The latest research shows that longer nights mean a leaner body, a fitter heart and a healthier mind. Kate Hilpern finds some good reasons to turn in early

Sleeping well is vital for physical, mental and emotional health. But there has been a gradual reduction in the average amount of sleep people take, with research showing that at any one time, one person in five feels unusually tired and one in ten has prolonged fatigue.

"Sleep is nature's way of providing us with rest, recovery and energy. There is nothing else that does the same thing," says Professor Colin Espie, director of Glasgow University's sleep centre. "But too many of us treat sleep like a commodity. We disrespect it – even treat it as a nuisance that gets in the way of waking hours." Others are victims of sleep conditions such as insomnia. Having a good night's sleep has never been more important.

Heart benefits

If you sleep less than six hours a night and have disturbed sleep, you stand a 48 per cent greater chance of developing or dying from heart disease and a 15 per cent greater chance of developing or dying from a stroke, according to a study from the University of Warwick. "The trend for late nights and early mornings is actually a ticking time bomb for our health, so you need to act now to reduce your risk of developing these life-threatening conditions," says co-author Professor Francesco Cappuccio.

Men over 65 who spend little time in deep sleep are at particularly high risk of developing high blood pressure, according to new research from Harvard Medical School. The study of 784 patients, published in the journal Hypertension, found that those getting the least deep sleep were at 83 per cent greater risk than those getting the most. High blood pressure increases the risk of heart attack, stroke and other health problems.

Lack of sleep causes stress on the body, causing the heart to beat faster, experts explain. Getting too much sleep – more than nine hours at a stretch – may be an indicator of illness, including cardiovascular disease, they add.

Weight control

Managing sleep levels could help in the battle against obesity. One study of 472 obese people, published in the International Journal of Obesity, involved participants eating 500 fewer calories per day, along with exercise most days. Those getting too little or too much sleep were less likely to have lost weight over the six-month period.

"Studies consistently show that the less sleep people have, the greater their chances of obesity," confirms Dr David Haslam, chair of the National Obesity Forum. "People think sleep is just sedentary, so it can't possibly help you lose weight, but lack of it mucks up our appetite hormones."

Dr John Shneerson, president of the British Sleep Society and consultant physician at Papworth Hospital's sleep centre, explains: "Our ordinary fat cells produce a hormone called leptin, whose job it is to switch off our appetite to help us maintain the right weight. Sleep deprivation reduces our leptin level, leaving us with a greater appetite. Our stomach and intestine produces another hormone called ghrelin, whose aim it is to increase our appetite when required. Sleep deprivation causes an increase of this hormone. The combination of the decrease in leptin and increase in ghrelin makes us eat more.

"Also, sleep deprivation puts increased stress on your body, making us produce more steroids from our adrenal glands, causing us to retain more fat in our body. The result of all these things is that no matter how hard people try to lose weight, they will have an uphill battle if they don't get a good night's sleep."

Mental Health

Most of us know that in the short term, poor sleep makes us weary, apathetic, forgetful and irritable. But in the longer term, it is linked to impaired performance, job problems, mood disorders and mental health problems, notably depression. So strong is this relationship that earlier this year, the Mental Health Foundation launched a campaign to highlight the importance of sleep in maintaining mental health.

"Lack of sleep needs to be treated as a major health issue," says Dr Dan Robotham, senior researcher at the Mental Health Foundation. "We are all au fait with the importance of diet and exercise, but sleep is often ignored."

Their report, "Sleep Matters", which was carried out with Glasgow University's sleep centre, found that people with insomnia were four times as likely to have relationship problems, three times as likely to feel depressed and three times as likely to suffer from a lack of concentration. "People can get stuck in a spiral where poor sleep leads to mental health problems, which leads to even worse sleep," says Dr Dan Robotham,of the Mental Health Foundation, lead author of the report.

Poor sleep can even lead to suicide. The University of Michigan found that people with two or more symptoms of insomnia were 2.6 times more likely to report a suicide attempt. Meanwhile, Columbia University Medical Centre in New York found that 12 to 18-year-olds who went to bed after midnight were 20 per cent more likely to think about suicide than those whose bedtime was 10pm or earlier, while those who had less than five hours sleep a night had a 48 per cent higher risk of suicidal thoughts compared with those who had eight hours of sleep.

Longevity

"Study after study shows that if you randomly select individuals, those that sleep around the seven hour mark live longer than those who sleep much shorter or longer," says Professor Kevin Morgan, from Loughborough University's sleep research unit.

One review of 16 studies from the UK, US, and European and East Asian countries, found that people regularly having less than six hours sleep were 12 per cent more likely to die over a 25-year period than those who got an "ideal" six to eight hours.

While a lack of sleep may be a direct cause of ill health, too much sleep may merely be a marker of ill health already, the researchers concluded, although Professor Morgan is less sure. "Sleep is a form of sedentary behaviour, so if you're spending nine to 10 hours inactive, it compromises your cardiovascular fitness. That alone can lead to a whole set of health problems."

Immune system

"Some of the earliest studies looking at sleep deprivation involved torturing rats to death by keeping them sleep deprived," says Professor Morgan. "What was overwhelmingly clear when they were dissected is that they were immunocompromised. Recent studies on humans have shown that people who work night shifts are immunocompromised. It's not that night shifts are bad for you – although they're not good for you – but more that night workers often manage their sleep timing badly."

Diabetes

Type 2 diabetes develops when the body makes too much insulin, but does not use the hormone efficiently to break down sugar in the blood. A stepping stone to the condition, known as "impaired fasting glucose", occurs when blood sugar levels are too high, but not high enough to constitute a diagnosis of diabetes. Researchers from the University of Buffalo in New York, found that those who slept on average for fewer than six hours a night during the working week were 4.56 times more likely to develop impaired fasting glucose than those sleeping six to eight hours a night.

How to sleep well

* Going to bed and getting up at roughly the same time programmes your body to sleep better.

* A clutter-free bedroom – certainly no television or computers – is essential for rest.

* Exercise helps give us restful nights, but it has the opposite effect if done near bedtime – except for sex, which is actually conducive to sleep.

* Aim to sleep for seven to eight hours. Some people need less or more, but it's only a minority.

* If your mattress is more than a decade old, replace it as the quality will have deteriorated by about 75 per cent and this could seriously affect your sleep. Read our reviews of the best mattresses to help you decide.

* Splash out on comfort. An exceptional pillow, such as the Winter Snow Goose Pillow from John Lewis, will help with posture, which in turn promotes good sleep. Meanwhile, silk sheets, such as those by Gingerlily, help regulate body temperature, preventing regular waking.