Irregular sleep linked to increased risk of heart disease
February 24, 2023 — Irregular sleep patterns, such as inconsistent hours of sleep each night or falling asleep at different times, may increase the risk of atherosclerosis, or hardening of the arteries, in adults over 45 years of age. suggests new research.
In particular, a change in sleep duration of more than 2 hours per night during the same week was associated with the development of hardening of the arteries.
“Poor sleep is associated with several cardiovascular diseases, including heart disease, hypertension and type 2 diabetes,” says study author Kelsey Full, PhD, an assistant professor of medicine at Vanderbilt University Medical Center.
“Overall, we found that participants who slept a different number of hours during the week (meaning one night they slept less, one night they slept more) were more prone to atherosclerosis than participants who slept about the same amount of time each night. ” she says.
finds were published in the Journal of the American Heart Association.
Atherosclerosis is the buildup of fatty deposits, known as plaques, on the walls of arteries. This can lead to narrowing of the arteries and reduced blood flow and oxygen to the body. The plaque can also burst and form a blood clot that blocks an artery, which can lead to a heart attack or stroke.
To explore the relationship with sleep, Full and colleagues studied observational data from more than 2,000 participants in the Multiethnic Atherosclerosis (MESA) Supplementary Sleep Study. The study included adults aged 45 to 84 from six US communities: St. Paul, Minnesota; Baltimore City and Baltimore County, Maryland; Chicago; Forsyth County, North Carolina; Los Angeles County, California; and North Manhattan and the Bronx, New York.
Between 2010 and 2013, study participants wore a wrist device that determined when they were awake and asleep for 7 consecutive days, and they completed a 7-day sleep diary. They also completed an overnight sleep study to measure sleep disturbances related to breathing, sleep phases, and heart rate.
The research team looked at sleep duration, or the total amount of time spent in bed in full sleep per night, and sleep time, which was defined as the time a person fell asleep each night. They measured the presence of plaque in the arteries by measuring calcium in the coronary arteries (or the accumulation of calcified plaque in the arteries), carotid plaques (or fatty plaques in the arteries of the neck), carotid intima-media thickness (or the thickness of the two inner layers of the arteries). arteries of the neck) and the ankle-brachial index (or narrow peripheral arteries), all of which indicate the presence of atherosclerosis.
Overall, the median age of study participants was 69 years, and 54% of them were women. About 38% identified as white, 28% as black or African American, 23% as Hispanic, and 11% as Chinese American.
Over a 7-day period, approximately 38% of participants changed their sleep duration by more than 90 minutes, and 18% by more than 120 minutes. Those who had irregular sleep patterns were more likely to be non-white, current smokers, have lower average annual income, shift work or not work, and have a higher average body mass index.
Participants who had more irregular sleep duration, which varied by more than 2 hours per week, were 1.4 times more likely to have high coronary artery calcium levels than those who had more regular sleep duration, which varied by more than 2 hours per week. 60 minutes or less. They were also more likely to have carotid plaques and an abnormal ankle-brachial index.
Those who had irregular sleep times (which varied by more than 90 minutes per week) were also 1.43 times more likely to have high coronary artery calcium than those who had more regular sleep times (which varied by 30 minutes or less).
“The biggest surprise for me was that 30% of study participants had a total sleep time variation of more than 90 minutes during the week,” says Full. “This is consistent with previous studies that suggest that a large proportion of the population has irregular sleep patterns, not just shift workers.”
More research is needed to understand the mechanisms, the authors write. Night-to-night variability in sleep duration and sleep time can lead to desynchronization of sleep and wake times and disruption of circadian rhythms.
“Sleep is a natural, repetitive phenomenon, and maintaining regularity helps keep the body stable and predictable,” says Michael Grandner, Ph.D., assistant professor of psychiatry and director of the Sleep and Health Research Program at the University of Arizona College of Medicine.
“When people have a very irregular sleep schedule, it can be harder for the body to make optimal use of the sleep it receives since it’s such a moving target.”
Grandner, who was not involved in this study, studied sleep irregularity and its association with cardiovascular disease, diabetes, obesity, and many other adverse outcomes.
“Healthy sleep is more than just getting enough sleep,” he says. “It also means quality sleep at the right time and regularly.”
