Late Night Lifestyles May Increase Risk for Heart Artery Hardening

What is Artery Calcification?

Artery calcification refers to the buildup of calcium in the arteries, leading to a hardening and narrowing of these vital pathways for blood flow. This process is subtle and gradual, often going unnoticed until it gives rise to blood clots, angina, heart attacks, or strokes due to the reduced passageway.

The Study on Artery Calcification and Circadian Rhythms

Recent medical research from the University of Gothenburg, Sweden, reveals a notable correlation between one's circadian rhythm or sleep pattern, and the development of artery calcification. Surprisingly, the affliction seems more common among those with a preference for evening activity, or "night owls."

Circadian Rhythms, Chronotypes, and Cardiovascular Health

The biological process linking circadian rhythms to the early stages of cardiovascular disease is crucial. The investigation, which featured in Sleep Medicine, delved into the existence of coronary artery calcification among 771 men and women aged between 50-64.

Within this study, participants were asked to classify their internal body clock or chronotype into one of five categories: extreme morning type, moderate morning type, intermediate type, moderate evening type, and extreme evening type.

The findings were eye-opening: a clear relationship was found between late sleep-wake habits and severe cases of artery calcification. 40.6% of participants who identified themselves as extreme night owls displayed severe coronary artery calcification, compared to only 22.2% of extreme morning larks.

Understanding our Chronotypes

• Harnessing the chronotype information, as was self-reported by the participants, the researchers divided a night's sleep into two halves. For the extreme morning group, half of the sleep was achieved by 02:55 AM, whereas for the extreme evening group, half the sleep was achieved by 04:25 AM. Other chronotypes had their mid-sleep times in between these two extremes.
• This data becomes crucial when creating personalized advice and preventive treatment of cardiovascular diseases.

The Role of Other Risk Factors in Atherosclerosis

Even though the study emphasized the significance of circadian rhythms, it didn't ignore the contribution of other risk factors for atherosclerosis such as blood pressure, blood lipids, weight, physical activity, stress, sleep quality, and smoking.

Healthier than Average – A Study Limitation

A noteworthy limitation surfaced as individuals who had previously experienced a heart attack were excluded from the study, implying that the study population was healthier than the general populace. Furthermore, the chronotype was self-reported, which could introduce degrees of subjectivity and inaccuracies.

What does this mean for our Health?

This study underscores the importance of sleep habits, alongside other lifestyle factors, in contributing to cardiovascular health. While modifying one's biological clock might be challenging, understanding how it influences health could lead to more personalized and effective preventive measures against ailments such as artery calcification and cardiovascular disease in general.

Study Notes

The study was part of the larger population study named the Swedish CArdioPulmonary bioImage Study (SCAPIS), aiming to illuminate the early signs of cardiac, vascular, and respiratory diseases. This ambitious project involves extensive health examination, including blood testing, functional assessment, advanced imaging, and more, of 30,000 randomly selected Swedes between 50-64 years. The Swedish Heart-Lung Foundation, the primary base of the project's funding, is closely working with universities and university hospitals across the nation.

Reference

Kobayashi Frisk, M., et al. (2024). Eveningness is associated with coronary artery calcification in a middle-aged Swedish population. Sleep Medicine.