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When Are You Most Likely to Have a Heart Attack?

02/02/2022 | 6 min. read

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Heart attacks, cardiac arrests, strokes, and other cardiovascular events often appear to strike at random times and out of the blue. Although they can occur at any time, researchers have documented fairly consistent clusters at certain hours of the day, days of the week, and times of the year. 

It’s good to be aware of these patterns and why they occur so you can take steps to sidestep associated increases in cardiovascular risk factors. 

Blood Pressure Is Higher in the Morning 

Morning increases in blood pressure are related to your circadian rhythms—the normal 24-hour fluctuations in sleep/wake cycles, hormones, body temperature, etc. Your sympathetic nervous system is activated in the early morning, and as levels of cortisol, epinephrine, and other hormones slowly rise, blood pressure increases. When you get out of bed and begin moving around, blood pressure rises even more. 

What does this mean for you? Although a rise in blood pressure is normal, morning hypertension is linked with an increased risk of cardiovascular events. I recommend taking your blood pressure an hour after awakening, before breakfast. If it is above 140/90 but normal at other times of the day, ask your doctor for a 24-hour salivary cortisol level test to see if cortisol is affecting your blood pressure. If you are on blood pressure medication, discuss the pros and cons of taking it at bedtime, as some studies suggest this may reduce cardiovascular risk.

Most Common Time to Have a Heart Attack or Stroke 

Many studies have shown that heart attacks and strokes are more common in the morning. In addition to the early surge in stress hormones and blood pressure, platelets are stickier at this time, so the tendency to produce blood clots increases. Plus, as you become physically active, your heart has to work harder.

All these factors increase the likelihood of plaque rupture, which occurs when the fibrous cap of an arterial plaque tears or ruptures. In response, blood clots form that may block blood flow and cause a heart attack. Plus, studies show there is also a significant uptick in strokes and transient ischemic attacks (TIAs) between 6 a.m. and noon. 

What does this mean for you? A study reported in the European Heart Journal shows that the best (and safest) time to go to sleep is between 10:00 and 11:00 pm. More cardiac events occur in those going to bed earlier or later, so that’s the ideal. Then, give yourself time to wake up slowly in the morning, stretching your legs before you rise to an upright position. If you have cardiovascular risk factors, I also recommend saving strenuous exercise (including sex) for the afternoon or evening. 

Do Heart Attacks Peak on Monday? 

Research dating back decades reveals that Monday mornings are prime time for heart attacks. A study published in the American Heart Journal, which looked at more than 156,000 hospital admissions for heart attacks, confirmed that the most “popular” day was Monday; the fewest heart attacks occurred on Saturday. The researchers reported that this was likely related to “psychosocial stress levels,” which tend to increase with the onset of the work week.

What does this mean for you? There is a strong link between stress and heart attack risk factors. Take time to relax every day, but be especially vigilant on Mondays—and get serious about adopting stress management techniques.

Patterns of Cardiac Arrest Are Changing

Half of heart disease deaths are caused by sudden cardiac arrest rather than heart attacks. Cardiac arrest is a glitch in the heart’s electrical system that prevents it from properly pumping blood. If normal heart rhythm isn’t restored within minutes, it is fatal. 

Although cardiac arrest used to follow a time and day pattern similar to heart attacks and strokes, the long-term Oregon Sudden Unexpected Death Study found that this is no longer the case. Analyzing data on 1,535 adults who died of sudden cardiac arrest, researchers revealed that only 14% occurred before noon. Afternoon was the most common time. Nor was there the expected peak on Monday. More cardiac arrests happened on Tuesday and Wednesday and the fewest on Sunday. 

Focusing on stress as a risk factor in cardiac arrest, the researchers commented, “... there appears to be some re-distribution of these psycho-social stressors. While the exact mechanisms need further investigation, it is tempting to speculate a potential role for the advent of the internet and smartphones, allowing for access to entertainment, social life, and even work activities 24 hours a day, 7 days a week.”

What does this mean for you? Slow down, unplug at a reasonable hour, go to bed by 10 p.m. on most nights, and work on managing stress. Along with a heart-healthy diet, regular exercise, and a good supplement program, these are key to lowering all cardiovascular risk factors.

More Heart Attacks Occur in Winter—and in Summer

There are several reasons for the well-documented winter increase in heart attacks and angina. Cold temperatures constrict the arteries and increase blood pressure, which can trigger plaque rupture and heart attacks. Snow shoveling and other strenuous outdoor activities are also associated with cardiovascular events, especially in individuals who don’t exercise much. Vitamin D deficiency, another risk factor, is more common in winter. Plus, winter is flu season, and viral infection-related inflammation is linked with a higher risk of blood clots, heart attacks, and strokes. 

The second peak time for heart attacks is summer. High temperatures dilate the blood vessels and can cause low blood pressure, which the heart compensates for by beating harder and faster. Dehydration increases inflammation and concentrates the blood, which stresses the endothelium, the protective inner lining of the blood vessels. According to a study published in the Journal of the American Heart Association, summer heart attacks are more likely to be caused by plaque erosion, which is characterized by damage to the endothelium. 

What does this mean for you? Be aware of these seasonal risk factors and do what you can to avoid them. Stay warm in winter and cool in summer, drink plenty of water, support your immune system with targeted supplements, and don’t overdo it.

What Is a Holiday Heart Attack? 

The holidays also contribute to the winter blip in heart attacks. More people die from cardiac events during the week between Christmas and New Year’s than any other week of the year. The busyness of the season, with shopping, gatherings, travel, etc., may interrupt your usual routines, including sleep, exercise, medication/supplement regimens, and other health habits. Plus, the holidays are a stressful time for many people, and chronic stress has adverse effects on your heart.  

There’s also a tendency to overindulge on rich, sugary, salty foods and on alcohol, and this too takes a toll. Emergency rooms see a spike in patients with arrhythmias not only on December 25 and January 1 but also around the “big game day” in February and the 4th of July—holidays known for binge drinking. This is so common that it even has a name: holiday heart syndrome

What does this mean for you? As Oscar Wilde famously said, “Everything in moderation, including moderation.” Enjoy the holidays but be mindful. Let your hair down, but don’t go hog wild on food and alcohol and take time to relax and chill out

Dr. Stephen Sinatra

Meet Dr. Stephen Sinatra

A true pioneer, Dr. Sinatra spent more than 40 years in clinical practice, including serving as an attending physician and chief of cardiology at Manchester Memorial Hospital, then going on to formulate his advanced line of heart health supplements. His integrative approach to heart health has changed the lives of hundreds of thousands.

More About Dr. Stephen Sinatra