Too Little Sleep May br Boost Your Risk of br Cardiovascular Disease, Says Study Participants in the study who br slept less than six hours a night br were 27 more likely to develop br plaque buildup in their arteries. The study was published br in the Journal of the br American College of Cardiology. It looked at 4,000 br adults with an average br age of 46 with no known br history of heart disease. Two-thirds of the br participants were men. The study also found that br those with a poor quality of br sleep were 34 more likely br to develop plaque buildup. José M. Ordovás, study author, via 'USA Today' Three studies presented last September revealed that those who slept between six and eight hours had a lower risk of heart disease.