For the study, researchers from the University of Chicago outfitted 495 healthy, middle-aged volunteers with actigraphs, a device worn on the wrist to measure movement and rest.
Accounting for some degree of movement during sleep time – hey, we’ve all been there with the tossing and turning! – the researchers determined that the study participants slept an average of 6 hours per night but spent about seven hours in bed, presumably waiting to fall asleep.
When the researchers compared these sleep readings to the results of computerized tomography, a test done to measure the volume of calcifications in the coronary arteries, they found that those who averaged five or fewer hours of sleep per night had a far higher incidence of “silent” heart disease. Specifically, 27% of those who slept five hours or less per night developed calcifications that can signal heart disease after five years, compared to just 6% of those who slept an average of seven hours or more. In addition, the researchers note that these folding hold true even after accounting for other known other known coronary risk factors, including high cholesterol, high blood pressure, diabetes and smoking. The researchers do note, however, that getting even an extra hour of shut-eye per night decreased the estimated odds of coronary calcification by 33 percent.
Although the researchers are not yet sure why too little sleep increases heart disease risk, they suggest that the key here could be stress hormones, a known heart disease risk factor and one of the reasons you might be staying up past your bedtime.
Based on these findings, the study’s lead researcher concludes that the study “does add to mounting evidence that there are subtle but potentially important health consequences of routinely sleeping very short hours – say, less than five hours a night.”
At a time of the year when sleep is, let’s face it, something we’re putting on hold until 2009, it’s important to remember that sleep is not a luxury or an act of the lazy. Instead, it is a necessity and something that you must do for optimal health. This study, for one, suggests the link between hitting the hay and heart health, but other researchers suggest that lack of sleep might also impact hormones such as leptin that help to control appetite, metabolism and body weight (something we’re all conscious of, especially during this time of the year!)
The bottom line? Do yourself a favor and sign up for a little extra shut eye this holiday season – your heart (and likely your waistline) will thank you for the extra effort!