Sleeping Too Much or Too Little Can Increase Risk of Heart Attack

Caroline Vetter, MSc

A new study from an international team of investigators has found that sleep may play a more significant role in heart health than previously thought.

An examination of more than 450,000 found that sleeping too much or too little sleep, even among non-smokers and those without genetic predispositions, can lead to an increased risk of myocardial infarction (MI).

“This provides some of the strongest proof yet that sleep duration is a key factor when it comes to heart health, and this holds true for everyone," said senior author Celine Vetter, MSc, assistant professor of integrative physiology at the University of Colorado Boulder.

In order to evaluate associations between sleep duration and incident MI, investigators from the University of Colorado Boulder, Massachusetts General Hospital, and the University of Manchester conducted a study using participants from the UK Biobank. A total of 461,347 participants were included in the study and analyses performed by investigators accounted for the effects of other sleep traits and genetic risk of coronary artery disease.

All 461,347 participants were free of relevant cardiovascular disease and were between the ages of 40 and 69. No participants had ever suffered MI and investigators followed participants for 7 years.

Investigators estimated multivariable adjusted hazard ratios (HR) for MI across habitual self-reported short and long sleep duration. Short was defined as fewer than 6 hours and long was defined as more than 9 hours. Investigators also performed 2-sample MR for short (24 single nucleotide polymorphisms) and continuous (71 single nucleotide polymorphisms) sleep duration with MI (43,676 cases/128,199 controls) and replicated results in the UK Biobank.

The investigators’ analysis revealed that, compared to those sleeping 6 to 9 hours per night, short sleepers had a 20% higher multivariable-adjusted risk of incident MI (HR: 1.20; 95% CI: 1.07 to 1.33) and long sleepers had a 34% increased risk (HR: 1.34; 95% CI: 1.13 to 1.58 — investigators noted these associations were independent of other sleep traits.

Additionally, those who were furthest from the 6 to 9 hour range had a higher risk of incident MI. Those who slept 5 hours per night had a 52% higher risk of MI and those who slept 10 hours per night had twice the risk compared to those who slept between 7 to 8 hours.

Healthy sleep duration mitigated MI risk in individuals with high genetic liability. MR results were consistent with a casual effect of short sleep duration on MI in CardiogramplusC4D and in the UK Biobank.

"It's kind of a hopeful message, that regardless of what your inherited risk for heart attack is, sleeping a healthy amount may cut that risk just like eating a healthy diet, not smoking, and other lifestyle approaches can," said lead author Iyas Daghlas, a medical student at Harvard.

This study, “Sleep Duration and Myocardial Infarction,” was published online in the Journal of the American College of Cardiology.