Adults who have irregular sleep patterns are 26% more likely to have a major cardiovascular event than those with a regular sleep-wake cycle, a new study shows.
Going to bed and waking up at different times was found to be detrimental to cardiac health and ‘strongly associated’ with an increased risk of myocardial infarction and stroke, even for people who got the recommended nightly hours of sleep, researchers found.
The study is one of the first to look at the patterns and habits of sleep rather than the length of time a person is asleep.
Published in the Journal of Epidemiology & Community Health, the findings highlight the importance of consistent sleep schedules as well as adequate sleep duration to reduce cardiovascular risks.
The researchers designed an observational study involving 72,269 people from the UK Biobank aged between 40 and 79 with no history of cardiovascular disease.
Each participant wore an activity tracker for seven days to monitor their sleep patterns, giving a Sleep Regularity Index (SRI) score. Participants with an SRI score of 87 were considered to have a regular sleep pattern, while those with an SRI score of less than 72 were categorised as irregular sleepers. People with SRI scores between this range were recorded as moderately irregular sleepers.
Cardiovascular health, including myocardial infarction, heart failure and stroke, was tracked over the next eight years using hospital records and death registries. Variables such as age, levels of physical activity, and general physical and mental health were accounted for.
Irregular sleepers were 26% more likely to have a major adverse cardiovascular event (MACE) compared to regular sleepers. Moderately irregular sleeping patterns led to an 8% increased risk of MACE.
As SRI scores increased to reflect more regular sleep patterns, the risk of MACE decreased, showing an almost linear relationship. This suggests that greater improvements in sleep regularity may lead to significant cardiovascular benefits.
The recommended amount of nightly sleep is between seven and nine hours for adults aged 18-64 and between seven and eight hours for adults over 65. Regular sleepers were more likely to meet this recommended quota than irregular sleepers (61% vs 48%, respectively).
For moderately irregular sleepers, meeting sleep duration recommendations could largely offset the elevated risk of cardiovascular events, the researchers found. For irregular sleepers, getting the recommended amount of sleep did not fully mitigate against the increased risk of MACE caused by the effects of changing sleep patterns.
The researchers suggested that although this is an observational study and further research is needed, sleep regularity could be a good predictor of future cardiovascular events.
The researchers commented: ‘Our results suggest that sleep regularity may be more relevant than sufficient sleep duration in modulating MACE risk.
‘Findings from this study suggest that more attention needs to be paid to sleep regularity in public health guidelines and clinical practice due to its potential role in cardiovascular health.’
A version of this article was originally published by our sister publication Nursing in Practice.
