Strokes and heart attacks most often occur at a specific time, study finds

The majority of heart attacks and strokes occur in the morning between 06:00 and 11:00.

This was reported to gazeta.ru by geneticist Konstantin Krutovsky, professor at the University of Göttingen and the Siberian Federal University, and leading researcher at the Institute of General Genetics of the Russian Academy of Sciences.

"This is related to the morning physiological adjustment of the body that occurs during the transition from sleep to wakefulness. Before awakening, the level of the stress hormone cortisol rises sharply, which increases blood pressure, raises heart rate, and mobilizes energy resources. This phenomenon is called the cortisol awakening response. For a healthy person, this is normal, but in people with cardiovascular diseases, such a strain can become a trigger for a heart attack or stroke," the doctor explained.

In addition, most people experience a morning rise in blood pressure associated with activation of the sympathetic nervous system and vascular tone.

"During this time, the heart works significantly harder than at night. Moreover, in the morning, blood becomes more prone to clot formation, which is associated with increased fibrinogen levels, heightened platelet activity, and decreased activity of clot-dissolving systems. As a result, the likelihood of a blood clot forming in the vessels of the heart or brain increases. This is further exacerbated by the fact that at night the blood vessels are relaxed, while in the morning they constrict under the influence of hormones and the nervous system. And if a vessel is already partially blocked by an atherosclerotic plaque, the morning constriction can reduce blood flow, cause the plaque to rupture, and provoke a clot," the scientist noted.

Therefore, some hypertension medications are recommended to be taken in the evening to prevent the morning blood pressure spike. People in the risk group are also advised to avoid sudden physical exertion immediately after waking up and to give the body 30 to 60 minutes.

"However, some studies show that in 'night owl' individuals, the morning peak of cardiovascular events may shift to a later time because their circadian rhythms are offset. This should also be taken into account," Krutovsky concluded.