Sleeping soon after dinner may raise stroke risk

Once again, mom was right: Don't eat too close to bedtime. A new study suggests that waiting at least an hour after dinner before going to sleep reduces your risk of stroke by about two-thirds.

And for every 20 minutes more that you wait, stroke risk drops another 10%, says researcher Cristina-Maria Kastorini, MSc, a nutritionist at the University of Ioannina Medical School in Greece.

The study does not prove cause and effect -- only that there seems to be an association between waiting an hour or more between dinner and bedtime and reduced stroke risk.

Results of the 1,000-patient study were presented here at the European Society of Cardiology Congress 2011.

Waiting an Hour After Dinner to Sleep Linked to Lower Stroke Risk

The study included 500 healthy people: 250 people who had had a stroke and 250 with acute coronary syndrome. Acute coronary syndrome is a common type of heart disease where typically there is reduced blood flow to the heart because of clogged arteries, which can lead to tightness in the chest and even a heart attack.

All filled out detailed questionnaires asking about their sleep habits as well as when and what they ate.

Compared with people who went to bed within an hour of dinner, those who waited 60 to 70 minutes were 66% less likely to have had a stroke. Those who waited 70 minutes to two hours had a 76% lower likelihood of having a stroke. After two hours, the reduction in risk started to taper off, for reasons as yet unexplained.

There was a hint that waiting an hour or more between dinner and bedtime might be associated with reduced risk of acute coronary syndrome.

The analysis took into account a host of heart disease and stroke risk factors -- age, sex, physical activity, weight, smoking, diet, family history of heart disease, high blood pressure, high cholesterol levels, and diabetes. Still, the people who didn't wait an hour or more after dinner to go to bed could have shared some unmeasured characteristic that explains the findings.

Why Waiting Longer Might Lower Stroke Risk

Although the study didn't delve into why waiting longer after eating to go to sleep might lower stroke risk, Kastorini tells WebMD that previous research suggests that eating too close to bedtime is associated with an increased risk of reflux disease. That in turn is associated with sleep apnea, a risk factor for stroke, she says.

American College of Cardiology President David Holmes, MD, professor of medicine at Mayo Clinic College of Medicine in Rochester, Minn., has another theory: "When we eat, blood sugar changes, cholesterol levels change, blood flow changes," he says. "All these temporary changes may affect stroke risk.

"While this work only involved a relatively small number of patients, time duration between dinner and sleep is something we need to study further," Holmes says. "For now, just remember, what your mom says is always right."