I just came across a blurb about the MORGEN Study (Monitoring Project on Risk Factors and Chronic Diseases in the Netherlands) which explores the associations of sleep duration and sleep quality with cardiovascular disease (CVD) and coronary heart disease (CHD).
Researchers surveyed more than 20,000 men and women ages 20 to 65 years old about their sleep quality and quantity. The followed them for 10 - 15 years and recorded morbidity and causes of death. Sleep quality was assessed by asking "Do you usually rise feeling rested?"
The results showed that people who slept less than 6 hours per night had a 15% higher risk of incident CVD and 23% higher risk of CHD, compared to people with normal sleep duration (7-8 hours per night). On its own, there was no increased risk of CVD in patients with normal sleep duration, but reduced sleep quality. However, in those with poor quality sleep and short sleep duration, there was a 65% increase risk of CVD and an 85% increase risk of CHD when compared to people who had good quality sleep and slept normal duration. Interstingly, there was no correlation between sleeping longer than 8 hours and CVD, a finding which contradicts other studies.
There is no mention of obstructive sleep apnea or obesity, which could affect sleep duration, sleep quality, and increase CVD and CHD risk.
The bottom line is that if you are sleeping less than six hours per night, and feel your sleep is poor quality, talk to your doctor. Your heart health could be in jeopardy.