A doctor checks as people sleep during the first Siesta Championship in Madrid, on Oct. 14, 2010. Almost 20 per cent of Canadians say they do not get enough sleep every night. (Paul White/Associated Press)

If you're having trouble sleeping, you're not yawning alone. An estimated 3.3 million Canadians age 15 or older have problems getting enough sleep, which may be affecting their health and quality of life.

The 2002 Canadian Community Health Survey found that just under one-fifth (18 per cent) of these people average less than five hours of sleep a night. This lack of shut-eye makes them more susceptible to health problems.

A September 2006 issue of Archives of Internal Medicine looked at the link between sleep and health.

"The theme that emerges throughout this issue is that sleep serves as an indicator of health and quality of life," guest editors Dr. Phyllis Zee and Fred Turek of Northwestern University Feinberg School of Medicine in Chicago wrote.

The importance of sleep

Researchers looked at how lack of sleep may affect the immune system. Chronic sleeplessness may harm the immune system, since lack of sleep is linked to an increase in cytokine molecules that control immune response.

The resulting inflammation and changes in blood chemistry may be behind a variety of diseases, such as heart disease, diabetes and neurological conditions.

"The foundations of good health are good diet, good exercise and good sleep, but two out of three doesn't get you there," said Dr. Anne Calhoun, a neurology professor at the University of North Carolina.

Molly Atwood is monitored while lying in a bed in the sleep and depression laboratory at Ryerson University in Toronto. Adults need seven hours of sleep per night, while adolescents need a bit more. (Darren Calabrese/Canadian Press)

Sleep is important in maintaining your health, say experts. Without it, you become more susceptible to health problems, such as heart disease, stroke, diabetes, obesity and depression.

One study on more than 1,400 middle-aged adults over four years found those with sleep apnea, in which the airway becomes repeatedly blocked and sleep is interrupted, were twice as likely to develop depression.

Physicians treating people for depression should address poor sleep habits, Zee said.

A French study of nearly 600 people found a higher rate of sleep problems and daytime sleepiness among allergy sufferers, compared with a controlled group of people of the same age and sex who lived in the same area.

"The results show a significant impact of allergic rhinitis on all dimensions of sleep quality and, consequently, a lower quality of life as reflected by more somnolence [sleepiness], daytime fatigue and sleepiness, and impaired memory, mood and sexuality," Dr. Damien Léger of Assistance Publique Hôpitaux de Paris and colleagues wrote.

In the same issue of Archives of Internal Medicine, other studies concluded that men with diabetes and men with short or poor-quality sleep tended to have less control of their blood-sugar levels.

Skimping on sleep increases hunger

In 2004, researchers at the University of Chicago discovered that sleep loss could reduce the body's ability to regulate hormones that control hunger. This could lead to an increase in appetite and a preference for high-carbohydrate foods.

Research subjects who slept only four hours a night for two nights had an 18 per cent decrease in leptin, a hormone that tells the brain there is no need for more food, and a 28 per cent increase in ghrelin, a hormone that triggers hunger. "It provides biochemical evidence connecting the trend toward chronic sleep curtailment to obesity and its consequences, including metabolic syndrome and diabetes," said Eve Van Cauter, professor of medicine at the University of Chicago, in a press release.

As hunger increased in the research subjects, their food choices changed. After two nights of diminished sleep, the volunteers found foods such as candy, cookies and cake far more appealing than fruit, vegetables or dairy products.

"We don't yet know why food choice would shift," Van Cauter said. "Since the brain is fuelled by glucose, we suspect it seeks simple carbohydrates when distressed by lack of sleep."

Modern society seems to have forgotten the importance of sleep, according to Van Cauter.

"We are all under pressure to perform, in school, at work, in social and professional settings, and tempted by multiple diversions. There is a sense that you can pack in more of life by skimping on sleep. But we are finding that people tend to replace reduced sleep with added calories, and that's not a healthy trade."

Another study, presented at a conference sponsored by the American Academy of Sleep Medicine on June 11, 2007, suggested that people who don't get enough sleep are less likely to cook their own meals — and more likely to rely on restaurants and fast-food outlets for some of their meals. The study suggested that that could lead to weight gain or other nutrition-related problems. How much sleep is enough?

Experts say the amount of sleep varies from person to person. In general, most adults need about seven hours of sleep per night. Children and adolescents need even more — around nine or 10 hours each night.

The best measure of how much shut-eye you need is how you feel when you wake up. If you feel well and are energetic, then you likely had a good night's sleep.

Other research presented at the conference suggested that children who don't get enough sleep or suffer from sleep disorder symptoms are more likely to have trouble academically. Another study suggested that it's a good idea for airport baggage screeners to get a good night's sleep. The study found that sleep deprivation might impair the ability of baggage screeners to detect potentially dangerous items. It didn't affect the speed at which they were able to work, but accuracy in detecting potential problems did suffer. Will sleeping pills help?

Experts say sleeping pills can help in some cases, but should be treated as a form of temporary relief. Regular use could make the insomnia worse and change normal sleep patterns.

Sleeping pills can also be unsafe if your insomnia is caused by certain health problems. Find out from your doctor if sleeping pills would be helpful and safe for you.

Most popular sleeping positions

A study published on May 1, 2007, by the Better Sleep Council of Canada — which represents more than 450 manufacturers, retailers and suppliers from the mattress industry — found that Canadians tend to prefer one of five different sleep positions:

• Lying on the side with arms on the sides: Thirty-nine per cent of those surveyed chose this position. Lying on your side is recommended — as long as you maintain a slight bend in your legs.
• Lying on the side with legs bent: Twenty-eight per cent of those surveyed said they slept in this most recommended position. Experts say if you sleep in this position, you should place a pillow between your knees to naturally support your hips and lower back.
• Lying on the back with arms by the side: Fifteen per cent of those surveyed preferred this position.
• Lying on the stomach: Eight per cent of Canadians surveyed preferred this position. Stomach sleeping is not recommended as it can cause stress for the lower back, neck and shoulders. A flat pillow under the hips and one under the head are recommended.
• Lying on the back with arms by the head: Five per cent of those surveyed preferred this position. Sleeping on your back is a preferred position because it puts the least stress on your joints and back.

The Cleveland Clinic offers these tips for the best positions for lying down or sleeping:

• Try to maintain the curve in your back (such as lying on your back with a pillow under your knees or a lumbar roll under your lower back, or on your side with your knees slightly bent).
• Do not sleep on your side with your knees drawn up to your chest.
• Avoid sleeping on your stomach, especially on a saggy mattress, since this can cause back strain and can be uncomfortable for your neck.
• Select a firm mattress and box spring set that does not sag. If necessary, place a board under your mattress.
• Try a back support to help you feel more comfortable. Try tying a rolled sheet or towel around your waist.