Research has shown that inconsistent sleep patterns, including both inconsistent sleep duration and inconsistent sleep timing, could increase atherosclerosis risk in individuals over the age of 45 in comparison to individuals having more consistent sleep habits.1✅ JOURNAL REFERENCE DOI: 10.1161/JAHA.122.027361
Atherosclerosis is the accumulation of fatty deposits on artery walls that can cause a narrowing of arteries and reduce blood flow, leading to heart attacks or strokes.
The study analyzed over 2,000 participants with an average age of 69 years, including men and women from different ethnic backgrounds who were free of cardiovascular disease.
Individuals wore a wrist device to track their sleep patterns and kept a sleep diary for 7 consecutive days. They also underwent an in-home sleep study for 1 night to assess various sleep disorders.
Duration of sleep was determined as the total amount of time fully asleep in bed, while sleep timing was determined as the time an individual falls asleep every night.
The highest number of irregular hours individuals slept was a variation of over 2 hours in 1 week. Individuals with the highest irregular sleep timing varied the time falling asleep by over 90 minutes in 1 week.
The presence of artery plaque was gauged by measuring: the ankle-brachial index, which is the narrowing of peripheral arteries; carotid intima-media thickness, which is the thickness of the neck’s inner 2 layers; carotid plaque presence, which is the fatty plaque accumulation in neck arteries; and coronary artery calcium, which is calcified fatty plaque accumulation in arteries.
The study found:
- Individuals having sleep duration irregularity, varying by more than 2 hours in a week, had a 1.4 times more chance of having high coronary artery calcium scores, indicating an increased risk of cardiovascular disease.
- Individuals having sleep duration irregularity, varying by more than 2 hours in a week, had a 1.12 times more chance of having carotid plaque and almost 2 times more chance of having abnormal ankle-brachial index results.
- However, no significant association was observed between irregular sleep duration and abnormal carotid intima-media thickness.
- Individuals with more sleep timing irregularity, varying over 90 minutes in a week, had 1.43 times more chance of having high coronary artery calcium scores in comparison to individuals with more regular sleep timing of 30 minutes or less variation in a week.
- However, there was minimal evidence associating irregular sleep timing with other markers of cardiovascular disease.
The study highlights the importance of maintaining consistent sleep patterns to reduce the risk of atherosclerosis and related cardiovascular diseases.