Individuals With Varied Nightly Bedtime And Sleep Duration At Higher Risk of Cardiovascular Diseases

Inadequate sleep is becoming increasingly pervasive. Not only is getting a good sleep vital for your energy levels but also critical for your heart health. According to a new study, individuals who frequently alter their amount of sleep and their bedtime each night are twice likely to develop heart diseases.

Previous researches have focused on shift workers since working during the nighttime can affect the body’s circadian rhythm and increase one’s risk of cardiovascular diseases. But, the experts at the Brigham and Women’s Hospital and Harvard Medical School in Boston, Massachusetts opined that the circadian disruption may occur even outside of shift work, especially due to modern lifestyle factors such as increased use of television and screen time at night.

“Even if they tend to go to sleep at certain times, by following that lifestyle or behavior, it can interfere with their planned sleep timing," Medscape Medical News quoted the study’s lead investigator Tianyi Huang, ScD, MSc. "One thing that surprised me in this sample is that about one-third of participants have irregular sleep patterns that can put them at increased risk of cardiovascular disease. So I think the prevalence is higher than expected," Huang added.

The study included 1992 participants in the age group 45-84 who were free of CVD. After following them for about 4.9 years, the researchers found that about 786 of them had sleep duration deviation >90 minutes and 510 of them had sleep-onset timing standard deviation >90 minutes.

They reported 111 CVD events such as myocardial infarction, coronary heart disease death, stroke, and other coronary events during this period.

The findings of the study suggested that compared to those who had less than 1 hour of variation in sleep duration, the ones with sleep duration that varied 61-90 minutes had a higher risk of CVD. This was found to be true irrespective of sleep-related risk factors including BMI, systolic blood pressure, total cholesterol, insomnia symptoms, smoking status, and sleep apnea.

Moreover, every 1-hour increase in sleep duration variation was linked to a 36% higher risk of heart diseases. They found the results to be similar for both the regularity of sleep duration as well as that of sleep timing. This highlighted the fact that both can contribute significantly to circadian disruption and thereby lead to the development of CVDs.