Take two naps and call me in the morning

Sleep is critical to health and MDs should be asking patients about it, a professor argues
Sep. 24, 2006, KENNETH KIDD, FEATURE WRITER, The Toronto Star

So, how have you been sleeping lately? Getting at least a good seven hours? And when was the last time your doctor asked you those kinds of questions?

If you're like most patients, chances are the subject never came up. "Most physicians, they don't get a lot of education in medical school about sleep," says Phyllis Zee, a professor at Northwestern University's Feinberg School of Medicine in Chicago. "Because of that, they don't see it as an important parameter and they're not usually asking their patients about sleep problems."

Zee, who specializes in sleep patterns and disorders, thinks that needs to change. Thanks to a growing body of research that links lack of sleep with everything from obesity, type-2 diabetes and depression to hypertension and cardiovascular problems, she believes doctors should routinely assess their patients' sleep habits, just like they check blood pressure.

"Over the last 10 years, we've been bombarded with the importance of nutrition, with the importance of exercise," says Zee. "I think we need to add sleep. They're all related, all these three areas."

Toward that end, the journal Archives of Internal Medicine — with Zee on board as a guest editor — has devoted its entire current issue to sleep, especially the connections between sleep deprivation and chronic diseases.

It comes at a time when North Americans are spending less time sleeping than ever — as a matter of lifestyle, commuting or long work hours. In the U.S., for instance, nearly a third of all men and women aged 45 to 64 now sleep only six hours or less each night, up from about 22 per cent as recently as 1985.

That's much less than the nightly seven to eight hours that Zee says people need to stay healthy. Perhaps not coincidentally, both obesity and diabetes have been on the rise of late.

"If you take normal individuals and sleep-deprive them by about four or five hours a day, for less than a week, their glucose begins to look like somebody who is pre-diabetic," says Zee. "It's very possible that if a patient with, let's say, diabetes, is not sleeping well, that may affect their ability to control their glucose."

Lack of sleep also brings changes in two key hormones — leptin and ghrelin — that regulate appetite. Leptin, for instance, is produced by fat cells, and "if your leptin levels are high, that tells you, `Don't eat any more,'" says Zee. "Leptin levels go down under sleep-deprivation conditions, and that would probably make somebody hungry."

Sometimes, the links between sleep disorders and a particular disease are fairly well established.

One study, for instance, shows that even a mild increase in the severity of someone's sleep apnea, or stoppages in breathing, almost doubles their risk of developing depression. "There is, indeed, a causal link between the two," says Zee.

Mostly, though, we still don't know the precise mechanisms that connect lack of sleep with a variety of health problems. It could, for instance, come via changes in the immune system brought about by sleep deprivation.

Nor do we always know which constitutes "cause" and which is "effect." Does sleep deprivation from causes other than apnea bring on depression, or is it the other way around? In many cases, says Zee, the association is probably one of mutual reinforcement.

That likely explains why so few doctors routinely ask about the sleep habits of their patients, says Michael Evans, associate professor of family and community medicine at the University of Toronto. "What's the chicken and what's the egg?" he asks.

Perhaps a third of all patients suffer from some kind of sleep problem, whether because of stress, anxiety, shift work or simply bedrooms decked out like media centres. Asking about their sleep habits could, in other words, lead everywhere and nowhere.

But Evans says that doesn't diminish the importance of sleep. "The effect on chronic disease is significant."

It's just that, with all the recent advances in medical science, the profession now tends to look at very specific problems and treatments as if they occupied their own silos.

That could change. Earlier generations of doctors did spend more time on issues of overall health and lifestyle, says Evans, abiding by the old adage that "a good laugh and a good sleep are the best tools in a doctor's bag."

"You might see it circle around again," he says of a renewed emphasis on lifestyle. "There will be more and more on the basics."

Recently, for instance, Evans reviewed an Italian study of men suffering from erectile dysfunction, in which the patients were sent away to a spa rather than given medication. "It cured a third of them," he says. "Some of the upstream (lifestyle) changes are really more powerful solutions."

Which, says Zee, is just another way of saying that mothers probably had it right all along.

"Your mother would say, `You better get enough sleep because otherwise you're going to catch a cold.' They knew something about it, that there was a relationship."