Can't sleep at night? A new study published in the journal Sleep has found that people who suffer from insomnia have heightened nighttime blood pressure, which can lead to cardiac problems. The investigation, which measured the 24-hour blood pressure of insomniacs compared to sound sleepers, was conducted by researchers from the Université de Montréal, its affiliated Hôpital du Sacré-Cœur de Montréal Sleep Disorders Centre and the Université Laval.

"Over many years, chronic insomnia can have negative effects on the hearts of otherwise healthy individuals," says lead author Paola A. Lanfranchi, a professor in the Université de Montréal Faculty of Medicine and researcher at the Hôpital du Sacré-Cœur de Montréal Sleep Disorders Centre. "Whereas blood pressure decreases in regular sleepers and gives their heart a rest, insomnia provokes higher nighttime blood pressure that can cause long-term cardiovascular risks and damage the heart."

The findings are important given that insomnia, which is a chronic difficulty falling or staying asleep, affects up to 48 percent of the population at some point in their lives. As part of the study, the scientific team recruited 13 otherwise healthy chronic insomniacs and 13 good sleepers. Subjects spent 40 hours in the sleep laboratory: two nights for adaptation and one for monitoring followed by the intervening day.

"Blood pressure cycles are mainly linked to the sleep-wake cycle," says co-author Jacques Montplaisir, a professor in the Université de Montréal Department of Psychiatry and director of Hôpital du Sacré-Cœur de Montréal Disorders Center. "Since blood pressure is heightened among insomniacs, those with overt cardiac disease are particularly at risk for progression of the disease."

The article "Nighttime Blood Pressure in Normotensive Subjects With Chronic Insomnia: Implications for Cardiovascular Risk," published in Sleep was authored by Paola A. Lanfranchi, Marie-Hélène Pennestri, Lorraine Fradette, Marie Dumont and Jacques Montplaisir of the Université de Montréal and its affiliated Hôpital du Sacré-Cœur de Montréal, as well as Charles M. Morin of the Université Laval.

This study was funded by the Canadian Institutes of Health Research, the Heart and Stroke Foundation of Québec and the Fonds de Recherche en Santé du Québec.