Sleeping less than six hours every night increases a person's risk of developing cardiovascular diseases than those who sleep between seven and eight hours a night, according to a study.
The research, which was a study published in the Journal of the American College of Cardiology (JACC), suggests that poor quality of sleep increases the risk of atherosclerosis - a condition wherein arteries became hardened and narrowed due to a plaque buildup around the artery wall.
The study involved 3,974 bank employees in Spain from the PESA CNIC- Santander Study with an average age of 46 years. The participants have no known heart disease history, and two-thirds of them were men. In seven days, all of them were asked to wear an actigraph - a device that measures every movement or activity - to measure their sleep.
The participants were also divided into four groups: those who slept more than eight hours, those who slept seven to eight, those who slept six to seven hours, and those who slept less than six hours. Then, they underwent cardiac CT scans and 3-D heart ultrasound to check for heart disease. Researchers used the state-of-the-art 3-D ultrasound to measure atherosclerosis not only in the heart but throughout the body as well.
The research team has found that those who slept less than six hours were 27 percent more likely to develop atherosclerosis throughout their body than those who slept seven to eight hours. Additionally, those who had a poor quality of sleep were 34 percent more likely to have atherosclerosis than those who had a good quality of sleep. The quality of sleep is defined as how often a person woke up during the night, as well as the frequency of movements during the sleep which reflect the sleep phases.
The study also suggests sleeping more than eight hours every night might increase the risk of atherosclerosis as well, as women involved in the study who slept more than eight hours per night were found to have an increased risk of atherosclerosis. Caffeine and alcohol consumptions were also higher in participants with short and disrupted sleep.
This latest study is said to be different from previous studies on heart health and sleep, said senior study author José M. Ordovás, Ph.D. Their research is larger than others and participants involved in the research are healthy. In many previous studies, participants involved were either suffering from sleep apnea or other health problem, while others rely on questionnaires. But, researchers said they used actigraphs in their study to obtain objective measures of sleep.
