Watch out: Sleeping more than eight hours may increase risk of heart disease, according to a report in SLEEP (August 2010). More specifically, sleeping for over seven hours per day on a regular basis, and sleeping for under seven hours per day regularly, is associated with cardiovascular disease risk.
People in the study who slept five or fewer hours per day (including naps) had a two times higher risk of cardiovascular disease than that of subjects who claimed seven-hour sleep durations. However, for subjects who reported nine-hour sleep durations, they too had an increased risk of cardiovascular disease.
Before you conclude that people who snooze a lot have higher heart disease risk because such individuals are lazy and thus don’t exercise and don’t eat healthful foods, the research here was adjusted for the following variables that can affect heart disease risk: smoking, drinking, exercise, diabetes, body mass index, hypertension, diabetes, age and gender, among others.
So there goes the theory that people who slumber under five hours are high strung workaholics who subsist on heart-harmful foods, and that people who spend too much time in bed are also probably too lazy to do aerobic exercise.
What’s even more disturbing about these study findings is that even among seemingly healthy people, sleep disturbances might be a risk factor for any kind of cardiovascular disease, says principal investigator Anoop Shankar, MD, PhD, Associate Professor in the Department of Community Medicine at West Virginia University School of Medicine in Morgantown, W.V.
These conclusions are based on data from over 30,000 adults who took part in the 2005 National Health Interview Survey. They answered this question: “On average, how many hours of sleep do you get in a 24-hour period?” The term “cardiovascular disease” covers the conditions of coronary heart disease, heart attack, angina and stroke.
The American Academy of Sleep Medicine recommends 7-8 hours of sleep a night, yet this recommendation cuts into (for lack of a better term) the findings of the NHI Survey. Eight hours is the top of the AASM’s recommendation, yet eight hours is also one of the durations associated with higher risk of cardiovascular disease!
So if you normally average eight hours of sleep a night, what should you do? The study authors don’t have a recommendation for this specific question. However, they point out that “long sleep duration” may be tied to some underlying breathing disorder related to sleep, or simply that of poor quality of sleep.
Another point made was that the study had a cross-sectional nature, and thus, was not sufficient enough to determine cause and effect. Nevertheless, doctors are urged to inquire about the habitual sleep habits of patients.
As for short sleep duration hiking up risk of cardiovascular disease, the reasons are far clearer. For starters, sleep deprivation (either in the form of one short block of, say, five hours, or a total of just five or fewer hours accumulated while lying in bed for eight hours) can cause impaired glucose metabolism. This can lead to insulin resistance, a forerunner of type 2 diabetes. This stinks because insulin resistance increases risk of heart attack and stroke! Short sleep duration can also raise blood pressure and disrupt other body functions, thereby increasing risk of hardening of the arteries.
If you sleep for short periods due to busyness, then something needs to go, so that you can sleep more. If you suffer from insomnia, there are natural solutions for this, and one of the best treatments for insomnia is regular, structured exercise — which of course, will lower risk of cardiovascular disease.