The Role of Circadian Misalignment due to Insomnia, Lack of Sleep, and Shift Work in Increasing the Risk of Cardiac Diseases: A Systematic Review

Around 121.5 million people suffer from cardiovascular diseases globally. The risk of cardiovascular diseases increases with advancing age in both genders. Circadian rhythm is responsible for a streamlined functioning of various body functions. Certain functions and hormones have their peak levels according to the biological day or night of circadian rhythm. Shift work and sleep disorders like obstructive sleep apnea can cause circadian misalignment that affects different metabolic, immunological, and cardiovascular functions, which ultimately increases the risk of cardiovascular diseases. We systematically searched the online database PubMed to find papers on randomized controlled trials (RCTs) from the past five years, evaluating the role of shift work and different sleep disorders in causing circadian misalignment and its effect on the risk of cardiovascular diseases. Fifty papers were shortlisted, and after the application of various inclusion and exclusion criteria, 18 papers were chosen; and then after a thorough analysis of the text, eight papers were selected for the review. All papers were evaluated for quality. Two papers focused on the effect of shift work on cardiovascular diseases, whereas five papers evaluated the role of sleep disorders on circadian rhythm and the risk of cardiovascular diseases. Shift work and sleep-related disorders were found to cause circadian misalignment, and it was found to be associated with an increase in the risk of cardiovascular diseases. Managing these disorders can help reduce the risk of cardiovascular diseases.