The most dangerous times for heart attack and for all kinds of cardiovascular emergency — including sudden cardiac death, rupture or aneurysm of the aorta, pulmonary embolism and stroke — are the morning and during the last phase of sleep. A group from Harvard estimated this risk and evaluated that on average, the extra risk of having a myocardial infarction, or heart attack, between 6 a.m. and noon is about 40%. But if you calculate only the first three hours after waking, this relative risk is threefold
[this suggest that the best time to take aspirin and other blood thinners is first thing in the morning...]
