Why are heart attacks more frequent in the morning? – Featured

24 mars 2023

The morning seems a more risky period for our heart. Many studies have already shown that the risk of myocardial infarction was higher there than at any other time of the day. But why ? Let’s take stock with Pr Alain Furber, president of the French Federation of Cardiology.

Myocardial infarctions, more commonly known as “heart attacks”, have become increasingly common and can strike anyone. However, it seems that in the majority of cases, these accidents occur in the early hours of the day. And it’s no coincidence: you probably know that all the functions of our body evolve during the day, according to a 24-hour cycle. This is the famous circadian rhythm, otherwise known as the “biological clock”.

A peak between 9 a.m. and 11 a.m.

For Professor Alain Furber, “ the incidence of myocardial infarction is also influenced by the circadian rhythm with a peak frequency between 9 a.m. and 11 a.m. according to studies. During this period corresponding to a phase of activity, there is a stimulation of the sympathetic nervous system (the adrenergic system) as well as an increase in the secretion of certain hormones such as cortisol (the stress hormone) leading to an increase in heart rate and blood pressure variations. These physiological variations increase the risk of rupture of atherosclerotic plaques and therefore the occurrence of a myocardial infarction, especially since these mechanisms also lead to an increase in platelet aggregation.. »

Worse between 11 p.m. and 1 a.m.

For the specialist, myocardial infarction severity also undergoes circadian variations, with an increase in infarct size and mortality around midnight. ” According to him, ” this is not due to the delay between the onset of chest pain and the unblocking of the coronary artery nor to the quality of care. In fact, experimental studies have shown a link between the size of the infarction and certain genes involved in the functioning of the cardiac biological clock.. Clearly, those whose symptoms occur around 11 p.m. could present more serious lesions than if the incident occurred at another time of the day.

Remember that myocardial infarction is a life-threatening emergency. Common symptoms are characteristic pain:

  • They act “like a vise” at chest level;
  • They persist and may extend to the jaw or to the left arm;
  • Finally, they can be accompanied by pallor, sweating, shortness of breath, nausea.
  • For women, symptoms vary, including fatigue on exertion, heart palpitations, cough, heartburn, digestive problems, back pain, chest pain radiating to the arm or shoulder, a feeling of exhaustion.

As Medicare reminds us on its website: “These symptoms often last more than five minutes and do not go away with rest. Don’t let the myocardial infarction evolve: call 15! “. We can never repeat it enough: the earliest possible treatment determines the extent of the infarction and greatly limits the risk of cardiovascular complications.

  • Source : Interview with Pr Alain Furber, President of the French Federation of Cardiology

  • Written by : Vincent Roche – Edited by: Laura Bourgault

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