8-plus hours of sleep may increase CVD risk
Research in the Journal of the Journal of the American Heart Association suggests sleeping beyond the recommended seven to eight hours a night can increase the risk of cardiovascular disease (CVD) and death.
“Although previous reviews have evaluated sleep duration and mortality and cardiovascular outcomes, these reviews have not quantified the CVR associated with each hour deviation below or above the recommended sleep duration,” wrote first author Chun Shing Kwok, MBBS, of Keele University in the United Kingdom. “In addition, none of the previous reviews assessed the influence of sleep quality.”
Researchers conducted a meta-analysis of 74 studies that represented more than three million individuals who self-reported their quantity of sleep. There were more than 242,000 deaths reported. They found:
- Study subjects who self-reported sleeping for less than seven hours had no significant adverse outcomes, including stroke or cardiovascular disease.
- Those who self-reported sleeping less than eight hours had a moderate increase of mortality.
- Those who slept for nine hours had a 14 percent increased risk of mortality.
- Those who slept for 10 hours had a 30 percent increased risk of mortality, a 56 percent increased risk of stroke, and a 49 percent increased risk of cardiovascular disease.
- And those who reported sleeping for 11 hours had a 47 percent increased risk of mortality.
Self-reported poor sleep quality was not associated with a significant increase in mortality or other outcomes. However, it was associated with a 44 percent increase in the development of coronary heart disease.
The researchers noted their findings support the clinical recommendations of the American Heart Association, in which sleep behaviors should be addressed to promote cardiac health. They also said public health campaigns addressing sleep behavior should include explicit guidelines for adequate sleep.
They added clinicians should consider nonrestorative sleep during patient assessment as sleep quality appeared to be a significant risk factor for coronary heart disease and also, individuals with excessive sleep patterns may warrant further clinical assessment.
“We found a significant association between deviations in sleep duration and both mortality and adverse cardiovascular outcomes,” the researchers concluded. “National guidelines should consider advocating this as the recommended sleep duration. We also found evidence that sleep duration above the recommended level of seven to eight hours was associated with a moderate degree of harm compared with sleeping less than the suggested duration.
"Furthermore, the greater the divergence from the recommended durations of sleep, the greater the association for cardiovascular harm and mortality. Our study suggests that abnormal sleep is a marker of elevated cardiovascular risk—and greater consideration should be given in exploring during patient consultations in both the duration and quality of sleep.”
As a senior news writer for TriMed, Subrata covers cardiology, clinical innovation and healthcare business. She has a master’s degree in communication management and 12 years of experience in journalism and public relations.