The link between poor sleep and poor health is well-documented, but new research suggests the adverse effects of insufficient sleep may be even more harmful than once thought. In fact, poor sleep is such a strong predictor of heart attack and stroke that researchers now say it should be considered as a risk factor for cardiovascular disease along with smoking, lack of exercise and poor diet.
According to the Centers for Disease Control and Prevention, poor sleep is a “public health epidemic” with one in four U.S. adult reporting insufficient sleep or rest at least 15 out of every 30 days. Sleep health — a function of quality, timing, and duration — affects a number of endocrine, metabolic, and neurological functions that are critical to the maintenance of physical and mental health.
The short-term effects of insufficient sleep are familiar to all of us: low energy, difficulty concentrating, increased appetite, and irritability, to name just a few. But what many people don’t realize is that a lack of sleep—especially on a regular basis—is associated with long-term health consequences, including chronic medical conditions that may lead to a shortened life expectancy. Studies have shown, for example, that people with chronic insufficient sleep have higher rates of obesity, diabetes, cardiovascular disease, and depression.
For this latest study, Dr. Valery Gafarov, of the Russian Academy of Medical Sciences in Novosibirsk, Russia, and colleagues wanted to know how poor sleep may impact a person’s risk of heart attack and stroke, which cause almost 80 percent of all deaths from cardiovascular disease. While previous research has established a link between poor sleep and adverse cardiovascular outcomes, most of the evidence has come from observational studies, making it difficult to determine which came first — the sleep problems or the physical disease.
“Sleep disorders are very closely related to the presence of cardiovascular diseases,” explains Dr. Gafarov. “However, until now there has not been a population-based cohort study examining the impact of sleep disorders on the development of a heart attack or stroke.”
The team recently presented their findings at EuroHeartCare 2015, the annual conference of the European Society of Cardiology.
Poor sleep linked to twice the risk of heart attack, up to four times the risk of stroke
The research was a part of the World Health Organization’s (WHO) Multinational Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA) program and the “MONICA-psychosocial” sub-study. The study included a nationally representative cohort of 657 men aged 25-64 with no history of diabetes, stroke or heart attack.
At study baseline in 1994, researchers used the Jenkins Sleep Scale to identify sleep frequency and any sleep difficulties among participants. Those whose ratings fell into the categories of “poor,” “bad” or “very bad” were considered to have a sleeping disorder. Then, over the next 14 years, the researchers recorded the incidences of heart attack and stroke to see if sleep quality at baseline predicted these later cardiovascular events.
Overall, nearly two-thirds (63 percent) of participants who had a heart attack during the study period also had a sleeping disorder. Compared to those without a sleeping disorder, participants with a sleeping disorder at baseline were found to be 2.0-2.6 times more likely to have a heart attack and 1.5-4.0 times more likely to have a stroke in the next 5-14 years. The risk was highest among those who were widowed or divorced, those who had professions that involved heavy to medium manual labor and those who had not completed high school.
“Sleep is not a trivial issue. In our study it was associated with double the risk of a heart attack and up to four times the risk of stroke,” says Dr. Gafarov. Based on these findings, he adds, “poor sleep should be considered a modifiable risk factor for cardiovascular disease along with smoking, lack of exercise and poor diet.”
According to the most recent guidelines from the National Sleep Foundation, adults aged 18-64 should get around 7-9 hours sleep each night, while those aged 65 and older should aim for 7-8 hours sleep each night.