A heart attack occurs when plaque within a coronary artery ruptures, forming a blood clot that blocks the vessel. This deprives the heart of oxygen and nutrients, leading to myocardial damage. Without prompt intervention, patients may experience a drop in blood pressure, arrhythmia, cardiogenic shock, severe heart failure, or death.

Master of Science, Doctor Nguyen Hoai Vu, from the Cardiology Department at Tam Anh General Hospital in Hanoi, states that biological rhythms, weather, lifestyle, and stress levels can influence heart attack risk. Individuals over 50 years old, those with underlying cardiovascular conditions, high blood pressure, diabetes, dyslipidemia, kidney disease, smokers, heavy drinkers, those with sedentary lifestyles, or prolonged stress are at the highest risk.

Daily Risks

Doctor Vu notes that myocardial ischemia does not occur randomly but follows the body's daily biological rhythm. The morning, specifically from 6 a.m. to 11 a.m., presents the highest risk for heart attacks. Upon waking, blood pressure and heart rate rapidly increase, while adrenaline, noradrenaline, and cortisol levels peak. This forces the heart to work harder, and blood platelets become more prone to aggregation, making blood clots harder to dissolve. This period also involves changing from a lying to a standing position, placing immediate strain on the heart.

The risk peaks around 6:30 a.m., when plasminogen activator inhibitor-1 (PAI-1), a protein that inhibits fibrinolysis, reaches its maximum level. This protein prevents the breakdown of blood clots, increasing the risk of heart attack and stroke. The second highest risk period during the day is the afternoon, from 2 p.m. to 6 p.m., when many individuals engage in physical activity or experience mental stress. The risk gradually decreases in the evening and at night, as the body rests and blood pressure and heart rate decline.

Patients experiencing a heart attack require prompt emergency care. Photo: Tam Anh General Hospital

Weekly Trends

Doctor Vu cites research indicating a significant increase in heart attack rates at the beginning of the week, with monday being the highest. This phenomenon, known as the "Monday Peak," is consistently observed across many countries. The reason is believed to be a combination of psychological pressure from returning to work after the weekend. Biological rhythm-induced hormonal changes and existing cardiovascular factors make the heart and blood vessels more sensitive, predisposing them to blood clot formation, which can lead to a heart attack.

Seasonal and Holiday Risks

Winter presents the highest heart attack risk of the year. In cold weather, blood vessels constrict, raising blood pressure. The body also becomes prone to dehydration as thirst signals may be reduced, leading to thicker blood. Furthermore, respiratory viruses can trigger systemic inflammation, impacting atherosclerotic plaques in the coronary arteries.

During seasonal transitions, erratic temperature changes, whether sudden cold snaps or excessive heat, stress the cardiovascular system. Hot weather causes dehydration and a sudden drop in blood pressure, while heart rate increases, potentially leading to myocardial ischemia.

Beyond weather factors, year-end and New Year holidays also see an increase in heart attack cases. This is attributed to social gatherings, consumption of fatty, salty, and sugary foods, excessive alcohol intake, sleep deprivation, or emotional stress. These factors, combined with cold weather, can elevate blood pressure and create conditions for heart attacks to occur.

To prevent heart attacks, Doctor Vu advises individuals to monitor their blood pressure, take medication regularly, exercise, eat healthily, get sufficient sleep, manage stress, and stay warm in cold weather. If warning signs of a heart attack appear, such as chest pain, shortness of breath, fatigue, nausea, or dizziness, seek medical attention immediately. Some heart attack cases lack typical symptoms, making it easy to miss the "golden hour" for emergency treatment.

Ly Nguyen