The next time you're thinking of burning the midnight oil or staying out late, you may want to reconsider. That's because a team of researchers from the University of Delaware, the University of Pennsylvania, Drexel University, and the University of Arizona College of Medicine looked at the duration and approximate time of sleep to see if there was a pattern between this and three major cardiovascular risk factors — smoking, poor diet and sedentary habits — which together contribute to around 40 per cent of cardiovascular deaths in the US and the UK.
By using data from the UK's Biobank Resource project, which aims to improve the prevention and treatment of a range of life-threatening illnesses including cardiovascular disease, the team were able to look at a large sample of 439,933 adults aged of 40-69 for a four-year period between 2006 and 2010.
During the study, participants were asked about their sleep habits. Short sleep was defined as less than six hours; adequate sleep as seven to eight hours; and long sleep as nine hours or more.
Participants also defined themselves as a morning person, a more morning than evening person, more evening than morning, or an evening person.
To find out more about how heart-healthy their daily behaviour was, they were also asked about their levels of physical activity, time spent using a computer or watching TV, fruits and vegetable intake, and smoking habits.
Results showed that getting the right amount of sleep, and at the right time, reduced the unhealthy lifestyle behaviours that are associated with poor heart health — such as sleeping for either too long or too short, going to bed late, smoking, remaining sedentary and eating fewer fruits and vegetables.
Commenting on the results, Freda Patterson, one of the study's co-authors said: “The data suggests that it's not just sleep deprivation that relates to cardiovascular risk behaviours, but too much sleep can relate as well. If we can modify sleep as a central risk factor, we might be in much better position to leverage or modify some of our most stubborn cardiovascular risk behaviors such as tobacco use.”
However, Patterson also acknowledged that the study had its limitations. Despite a huge number of participants, the sample lacked diversity. And as a large part of the data was based on self-report, it was also subjected to errors. The team now recommends further study in the area.
The study was published online in the journal Annals of Behavioral Medicine.