If the quantity is less than five hours sleep a day, including naps, will increase the risk of suffering from angina, coronary heart disease, heart attacks and strokes.
This research was conducted by Karin Zeitvogel in the Faculty of Medicine, West Virginia University and is written in the journal "Sleep"-published by the American Academy of Sleep Medicine (AASM) and the Sleep Research Society-Sunday edition (eighth) in Washington, U.S..
Karin says, age groups at greatest risk are under 60 years old who slept five hours or less a night. They are at risk of cardiovascular attacked three times more than those who slept seven hours.
David Dinges, chief of Sleep and Khronobiologi Unit at the Faculty of Medicine, University of Pennsylvania found that 142 adults who sleep for five days is very limited, slower to react and difficult to focus.
"One or two extra hours of sleep in the morning after a period of chronic sleep loss is useful for the recovery of alertness," says Dinges.
Parties AASM recommends: adults sleep seven to eight hours every night so as not exposed to the risk of heart disease. (AFP/Yun)