Staying up late might be unwise — new research finds that night owls are more prone to developing a common heart condition compared to early birds.
Atherosclerosis — the hardening and narrowing of arteries, which can lead to angina, blood clots, heart attack, or stroke — is almost twice as common in night owls, according to study results from Sweden’s University of Gothenburg that were published in the journal Sleep Medicine.
While past research has shown that those who stay up late face the risk of cardiovascular problems, this study is said to be the first to explore how circadian rhythm, a person’s 24-hour biological clock, specifically affects the heart’s arteries.
Of the study’s 771 participants between 50 and 64 years old, 144 described themselves as extreme morning types, and 128 identified as extreme evening types.
22.2% of the early-morning types had pronounced artery calcification — they were the group who fared the best. The extreme-evening group had the highest incidence of severe artery hardening, at 40.6%.
The other three groups — morning type to some extent, neither morning nor evening type, and evening type to some extent — fell in between.
“Our results indicate that the extreme evening chronotype may be linked not only to poorer cardiovascular health in general, but also more specifically to coronary artery calcification and to the process that leads to artery calcification,” study author Mio Kobayashi Frisk said in a statement.
Other factors that affect the risk of artery hardening include blood pressure, lipids in blood, weight, activity levels, stress, sleep, and smoking.
Ding Zou, who co-authored the study, stressed that circadian rhythm — a fragile cycle that can be easily disrupted — is a key factor in disease development.
“We interpret our results as indicating that circadian rhythm is more significant early in the disease process,” Zou said. “It should therefore be taken into account in the preventive treatment of cardiovascular diseases in particular.”