Cardiovascular disease causes one out of every three deaths in the US—and it has three main henchmen…

Heart attack, when a blocked cardiac artery cuts off blood flow to the heart muscle, affecting about 735,000 people each year. 

Sudden cardiac death (SCD), commonly known as cardiac arrest, when chaotic activity in the heart’s electrical system causes it to stop functioning—a condition that strikes 325,000 people yearly. 

Ischemic stroke, when blood flow is blocked to the brain, occurring in nearly 800,000 people every year.

If you ask most cardiologists what leads to these “acute cardiovascular events,” they’ll talk about conventional risk factors, such as elevated cholesterol, high blood pressure, a sedentary lifestyle, diabetes and smoking.

There’s more to the story: Roughly half of all acute cardiovascular events are precipitated by little-known physical, emotional and chemical stressors, according to research. Exposure to these stressors can trigger a sudden, potentially harmful increase in the activity of the sympathetic nervous system, the “fight-or-flight” mechanism that prepares the body to respond to stress by temporarily accelerating heart rate, raising blood pressure and increasing blood clotting. 

Because an estimated 85% of adults over age 50 have some degree of atherosclerotic cardiovascular disease, largely due to the risk factors listed above, the already-compromised arteries of the heart muscle or brain may not be able to handle these abrupt physiological changes…and you can end up suffering a heart attack, SCD or stroke. What you need to know…

Physical Triggers

Major surgery is the leading little-known physical trigger. Surprisingly, it’s not just heart surgery, but any invasive surgery that requires general anesthesia.

Important finding: Among more than 10 million adults (age 45 and older) who underwent a major noncardiac operation (such as orthopedic, gynecologic, vascular and neurosurgery), 3% of patients (or one in 33), on average, had either a heart attack or stroke while hospitalized, according to a nine-year study published in JAMA Cardiology. 

The risks were especially high for certain types of operations—nearly 8% of patients undergoing vascular surgery suffered a heart attack or stroke while hospitalized…and more than 6% undergoing chest (thoracic) surgery. Patients who were at greatest risk were older, obese, smoked and/or had chronic conditions such as diabetes, kidney disease or high blood pressure.

What can happen: The surgery may cause arterial plaque to rupture and form a blood clot, triggering a heart attack or stroke. 

And the risk for an acute cardiovascular event remains elevated for some time. One in 20 patients (5%) who had major noncardiac surgery had a heart attack within 30 days of the surgery, according to a study published in Annals of Internal Medicine.  

Self-defense: To protect yourself against an acute cardiovascular event during or after major surgery, improve your aerobic fitness—which is associated with lower resting heart rates—­before surgery. For example, in the study mentioned above, every 10 beat-per-minute increase in resting heart rate before surgery (for example, 80 versus 70 beats per minute) was linked to about a 30% relative increase in the odds of a heart attack during hospitalization after surgery. 

You can achieve a good level of fitness simply by walking briskly (where you can have a conversation, but you’ll be breathing harder than usual) for at least 30 minutes, five or more times a week.

Emotional Triggers

Intense negative emotions—such as grief and anger—also stimulate the sympathetic nervous system, raising the risk for an acute cardiovascular event.

Compelling study: When researchers at Harvard Medical School tracked nearly 2,000 people (mean age of 62) over a five-year period, the risk for heart attack increased by 21-fold the day after the death of a “significant person,” such as a spouse, and declined on each subsequent day, according to research published in Circulation. The risk was greatest among those who already had heart disease.

When researchers reviewed nine studies on anger and acute cardiovascular events, they found that rates of heart attack, stroke and arrhythmia (a risk factor for SCD) all increased—some by nearly eight-fold—in the two hours after outbursts of anger compared with other times, according to research published in European Heart Journal.

Women with diagnosed heart disease are particularly vulnerable to negative emotions. Those who had the highest levels of  “psychological distress”—depression, post-traumatic stress, anxiety, anger, hostility and perceived stress—were 44% more likely to have a heart attack or stroke than those not experiencing those negative emotions, noted a study published in Journal of the American Heart Association.

How to protect yourself: If you have cardiovascular disease, stay fit (as described earlier) and take your prescribed medications, whether it’s a beta-blocker, statin or low-dose aspirin. These drugs may reduce one’s vulnerability to an acute cardiovascular event when an emotional trigger occurs. 

To reduce, or even prevent, the adverse consequences of negative emotions, complementary approaches include meditation, deep breathing, yoga, tai chi, mental stress-­reducing exercises and anger-management interventions. 

Chemical Triggers 

Air pollution and secondhand smoke are the two main chemical triggers of acute cardiovascular events.

Startling new findings: When levels of air pollution—from traffic and non-traffic emissions—in urban areas in New York state were tested and correlated with levels of hospitalization for acute cardiovascular events the next day, the higher pollution levels were linked to a more than doubled rate of hospitalization for arrhythmia and a nearly quadrupled rate of hospitalization for stroke, according to research published in Environment International.  

Two years after smoke-free legislation was implemented in ­Uruguay—prohibiting people from smoking indoors in the workplace or in public places—hospitalizations for heart attack decreased by 22%, according to research published in Tobacco Control

How to protect yourself: Limit your outdoor activities when pollution is high…and steer clear of people who are smoking. To monitor air quality in your local area, check the website AirNow.gov. As mentioned earlier, it’s also crucial to get (and stay) fit and take your cardioprotective medications, as prescribed. 

Other strategies to protect yourself against triggered cardiovascular events include avoiding unaccustomed heavy physical exertion (such as snow removal) and prolonged periods of sleep deprivation. It also helps to strive for strict enforcement of environmental regulations regarding air pollution.