Eight AM is a peak time for coronary events. Perhaps that is due to an increase in blood pressure; blood pressure dips during the night when people are sleeping and then increases when people arise and begin their daily activities. Ayas and colleagues1 have found that a sleep duration of more than 8 hours is associated with an increased risk of coronary events. Is it possible that longer sleep duration allows blood pressure to dip to lower levels, resulting in a greater change in pressure when people arise in the morning? Another possibility is an increased risk of blood clots. To minimize the risk of thrombosis, hospital patients are encouraged to get out of bed as often as possible to stimulate blood circulation in their legs. Is it possible that the higher risk of coronary events associated with longer sleep duration is due to a higher likelihood of thrombus formation?
Glaser JH, Glaser SK. To Sleep, Perchance to Increase the Risk of Coronary Events. Arch Intern Med. 2003;163(11):1374. doi:10.1001/archinte.163.11.1374-a