We’ve all seen dramatic scenes in movies in which a person suffers a heart attack following an angry outburst…after hearing of the death of a loved one…or while having sex.

But that’s just Hollywood melodrama, right? Well, actually, no.

An ever-increasing body of scientific evidence shows that some emotional and physical “stressors” can temporarily increase the risk for a heart attack, stroke or sudden cardiac death.

While these dangers are highest in people with heart disease, elevated cholesterol, high blood pressure or cardiovascular risk factors, such as smoking, obesity and/or a lack of exercise, even seemingly healthy people can be affected.

How to protect yourself: If you do aerobic or endurance exercise, such as brisk walking, jogging or walking up a treadmill incline, for 45 to 60 minutes, five days a week, you’ll be much less susceptible to cardiovascular triggers than people who get less exercise or are mainly sedentary, according to research. It’s believed that moderate-to-vigorous exercise increases the body’s ability to adapt or safely respond to periodic bursts of sympathetic stimulation (the body’s reaction to stress, such as a faster heartbeat or a spike in blood pressure), which can trigger cardiac events. Cardiac dangers you should know about…

DANGER #1: Getting angry. When you get really angry, your risk for a heart attack in the next two hours is two to nine times higher than it was before. Extreme anger can trigger arrhythmias (heartbeat irregularities), constriction of the arteries and an increase in blood clots. Important: Mere annoyance does not have the same effect—the risks are associated with physiological changes that can occur when a person is enraged.

Self-defense: Consider therapy if you’re prone to extreme anger—for example, during arguments or when someone cuts you off in traffic. In therapy, you’ll learn to respond appropriately to stressful situations and not to overreact.

Also helpful: If you’re unable (or unwilling) to get your emotions under control, ask your doctor if he/she recommends taking a daily aspirin to help prevent blood clots and/or a beta-blocker such as atenolol (Tenormin) to slow heart rate. The risk for an emotionally triggered heart attack may be lower in patients who use these medications.

DANGER #2: Receiving very bad news. Suppose you’ve just learned that a loved one has died or that you have cancer. Your immediate risk for a heart attack is six to 21 times higher than it was before you heard the bad news.

Two new studies reported in Circulation and The New England Journal of Medicine discovered that the risk of having a heart attack is highest on the day that you receive bad news, but the risk remains higher than normal for at least the next four weeks.

Self-defense: Regular exercise and some medications (such as a beta-blocker or aspirin) may reduce this cardiovascular risk. I also advise patients who have experienced emotional trauma to spend more time with family and friends. Staying socially active and maintaining close emotional ties have been shown to lower cardiovascular risks.

DANGER #3: Having sex. Some people may find it hard to believe that having sex could trigger a heart attack in a man.

What’s risky: Sex with an extramarital lover. According to one widely cited report, about 80% of heart attack deaths during or after sex take place in hotel rooms when people are not with their spouses.

Extramarital sex can cause higher-than-normal levels of arousal, which can produce an abrupt and sustained rise in heart rate and tax the heart. Also, these encounters are more often accompanied by increases in smoking or excessive alcohol use—both of which increase heart attack risk—than sexual relations with a spouse or steady partner.

Self-defense: Sex is safer if you exercise regularly. In general, sexual activity increases the heart rate by about 20 to 30 beats per minute. Extramarital sex may produce a considerably higher increase in heart rate. If you are not in good physical shape, start walking. Regular walking appears to prevent the triggering of a heart attack during or immediately after sex. Sex with a regular partner or spouse isn’t risky for people who are physically active.

DANGER #4: Watching sporting events. If you’re passionate about sports—and really care who wins—your heart could pay the price.

For example, during the World Cup soccer matches in Germany in 2006, there were 2.7 times more cardiac emergencies on the days when the German team played. When sports fans get excited, the heart rate can increase from about 70 beats a minute to 170 beats in some cases. In people with existing (sometimes undiagnosed) heart disease, this can trigger life-threatening clots or arrhythmias.

Self-defense: Don’t get carried away at sporting events…and don’t let the excitement of big games lead you into unhealthy practices—for example, forgetting to take your heart medications…drinking excessively…and/or smoking.

DANGER #5: Shoveling snow and other strenuous activities. Every winter, we read about people who die from a heart attack while shoveling snow. Even though cold temperatures usually are blamed, the main reason is overexertion of a diseased or susceptible heart.

When habitually sedentary people engage in unaccustomed, vigorous physical activity, they may be 50 to 100 times more likely to have a cardiovascular event, such as a heart attack, than those who don’t exert themselves.

Shoveling snow can cause increases in heart rate and blood pressure that are comparable to maximal exertion on a treadmill. The upper-body movements involved in shoveling are more taxing on the heart than movements involving only the legs. And breathing cold air can constrict the arteries that supply the heart. Holding one’s breath, muscle straining and mainly standing still while shoveling, all of which impair blood flow to the heart, also can create excessive cardiac demands.

Skiing, especially cross-country (and downhill, to a lesser extent), can tax the heart, too. At higher altitudes, the relatively low pressure of oxygen in the air makes the heart work harder.

Self-defense: Don’t shovel snow if you’re generally sedentary or have been diagnosed with cardiovascular disease or have risk factors (such as high blood pressure or a family history of heart disease). Hire someone to do it for you. If you must shovel, work slowly and for only a few minutes at a time. If possible, push the snow or sweep it rather than lifting it or throwing it. Consider buying an automated snowblower, which decreases demands on the heart.

If you are an amateur skier and mostly sedentary, gradually increase your activity levels for at least four weeks before a ski trip.

When outdoors in cold weather, wear layers of clothing, a hat, gloves and a scarf to cover your mouth and nose. This helps prevent constriction of the arteries.