If you don’t realize that not getting enough sleep may lead to health problems, then you don’t know jack. You also may not know JACC, which stands for the Journal of the American College of Cardiology. JACC is the journal that just published a study that found a potential association between sleeping less than 6 hours a night and atherosclerotic lesions in different blood vessels of the body.
Does the thought of your blood vessels getting narrower and narrower with growing cholesterol plaques in your blood vessel walls keep you up at night? If so, that could only make things worse for you, at least according to the JACC study. For the study, a research team from the Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), the Hospital Universitario Puerta de Hierro, and the IMDEA Food Institute, CEI UAM þ CSIC, in Madrid, Spain, studied 3,974 bank employees in Spain. No, this wasn’t to plan a bank heist to fund their research. Instead, they wanted to study the sleep patterns and the blood vessels of these bank employees (average age: 45.8 years old: 62.6% men).
The sleep part of the study involved watching the study participants’ sleep habits for 7 days. By watching, I mean placing small watch-like devices called actigraphs on each participant to measure their activity and movement. Based on the actigraph readings, the research team then were able to classify each of the study participants into one of four different groups based on how many hours each slept each night: very short sleepers (less than 6 hours), short sleepers (6 to 7 hours), the so-called reference group (7 to 8 hours), and long sleepers (more than 8 hours). Additionally, they measured how often the participants woke up and moved at night.
The heart part of the study, along with the femoral and carotid parts, came when the study participants underwent 3D ultrasounds and CTs of their hearts, necks, and legs to look for atherosclerosis in the arteries in these locations. An atherosclerotic lesion is the build up of cholesterol and other gunk in the wall of your blood vessel. This so-called “plaque” of gunk can keep growing larger thus progressively narrowing the vessel, sort of like reducing a four lane highway to three, two, one, or even zero lanes.
When the blood vessel gets too narrow, badness starts to happen. The blood vessel can no longer provide enough blood and oxygen to whatever parts of the body depend on the blood vessel. This may be your heart muscles (which can result in a heart attack), your brain (which may cause a stroke), your kidney (which can lead to kidney failure), or other part of your body. Plaques can also break off and travel through your blood stream like a big wad of toilet paper and then block blood vessels elsewhere. If you haven’t figured it out by now, you don’t want more atherosclerotic lesions in your body.
Additionally, the research team collected other information on each participant to get a better sense of his or her overall risk of cardiovascular disease. This included info on their body weights and sizes, diets, alcohol consumption, and smoking behaviors. They also determined whether each participant had obstructive sleep apnea or symptoms of depression.
Armed with all this information, the research team then used statistical analyses to determine if there was an association between sleep length or quality and the presence of atherosclerotic lesions. The results were not good for very short sleepers. Those who got less than 6 hours of sleep a night were 27% more likely to have atherosclerotic lesions in various arteries than those who got 7 to 8 hours of sleep a night. Oh, and as they say with shoes and sushi, quality seemed to be as important as quantity. The 20% with the worst quality of sleep (the most waking and movement) were 34% more likely to have atherosclerosis compared to others who got better quality sleep.
Of course, this study could only show associations and not prove cause and effect. The study did not measure everything that could affect both your sleep and your blood vessels such as stress levels. This could explain why the study also found that women who were long sleepers (longer than 8 hours a night) had more atherosclerosis than those who got 7 to 8 hours of sleep. For example, you may end up sleeping longer if you don’t have good work or social situations to occupy you, unless, of course, you are LeBron James and average 12 hours of sleep a day.
Nevertheless, these study results are not surprising and add to the growing body of evidence that less and worse sleep could increase your risk of cardiovascular disease. Previous studies have shown links between less sleep and risk factors such as obesity and high blood pressure. Nighty-night time is when your body heals and restores itself, which could include fixing the damage in your blood vessel walls. Missing this time could be like running your car constantly. Thus, you may want to take advice about getting a good night’s sleep to heart. Otherwise, you may end up taking it in your heart, brain, and other parts of your body.