People who sleep badly or not long enough have an increased risk of developing cardiovascular disease. This does not apply to people who only sleep for a few hours, but wake up feeling fit and rested. Researchers from the National Institute for Public Health and the Environment (RIVM) and Wageningen University studied the link between the duration and quality of sleep and the incidence of cardiovascular disease among a group of twenty thousand people. Researcher Marieke Hoevenaar-Blom hopes to be awarded a PhD by Wageningen University, part of Wageningen UR, for this research on 1 March.
The research team concluded that people who sleep for less than six hours have on average a fifteen percent higher risk of developing cardiovascular disease than people who sleep for seven to eight hours. Short sleepers who also sleep badly are doubly unfortunate. The research showed that this group has a 65% higher risk of cardiovascular disease when compared with people who sleep soundly for seven to eight hours. Short sleepers who wake up feeling fit and rested have the same chance of suffering a heart attack or stroke as long sleepers.
The researchers think that short sleepers who wake up feeling fit enjoy a high quality of sleep. The team found that long sleepers (who sleep for nine hours or more) are at no extra risk, despite claims to the contrary resulting from previous studies.
The findings mean that sleep can be added to the list of traditional positive lifestyle factors (healthy eating habits, not smoking, moderate alcohol consumption and sufficient exercise). People who follow these ‘lifestyle rules’ have a 57% lower risk of developing cardiovascular disease, and their chance of dying from cardiovascular disease is 2/3 lower. These figures compare with people who follow just one of these lifestyle rules. So a healthy lifestyle combined with a good night’s sleep reduces the risk of cardiovascular disease by up to 65%, and the risk of dying from cardiovascular disease by a staggering 83%.
The research is based on an analysis of an extensive dataset (the MORGEN project carried out by RIVM), which collected data on the eating habits, lifestyle and risk factors of 20,000 people from Amsterdam, Doetinchem and Maastricht. Statistics were also kept on how many of these people suffered or died from cardiovascular disease during the ten to fifteen years after the study was launched.