Two very large studies have confirmed that smoking increases the risk of a first heart attack by more than 100% in some people.^{1, 2} Women were found to be at greater risk than men; “inhalers” were almost twice as susceptible as non-inhalers. giving up smoking is critical for reversing this risk. According to one study, female ex-smokers who had not smoked for three or more years were “virtually indistinguishable” from women who had never smoked in terms of heart attack risk.³ Exposure to secondhand smoke, which increases infarct size in animals⁴ and impairs heart function and exercise tolerance in heart attack survivors,⁵ should also be avoided. For people who have already had a heart attack, giving up smoking is associated with a significant decrease in mortality.⁶

Routine, moderate exercise is preferred over excessive exertion for people at risk for heart attacks. Research indicates that heart attack risk rises six-fold for one hour immediately following heavy physical activity (compared to moderate or no activity), particularly among people who are sedentary.⁷ This risk is more than five times less in people who exercise four or more times per week.⁸ Most studies show that regular, moderate exercise reduces overall heart attack risk. Therefore, researchers and doctors recommend that susceptible individuals engage in an exercise programme.⁹ Exercise recommendations for people who are at risk or who have a history of heart attack need to be custom tailored to the individual. Therefore, anyone with a heart condition or anyone over the age of 40 should consult a healthcare professional before beginning an exercise plan.

Although sexual activity can trigger a heart attack, the risk is very low and¹⁰ is no greater for people with a history of angina or heart disease. Doctors recommend regular, moderate exercise to further reduce this risk.

Obesity is associated with an increased risk for heart attack, particularly among younger people.¹¹ One study found this relationship increased in women who also had a history of diabetes or high cholesterol.¹² Doctors encourage overweight people who are at risk for heart attack to lose the extra weight.

Type A behaviour is typically defined by time-conscious, impatient, and aggressive feelings and the behaviour that arises from those feelings. Type A behaviour has been linked to increased heart attack risk in some,¹³ but not all, studies.¹⁴ The link between personality and heart attack remains unclear.¹⁵ In the study with the most hopeful outcome, psychological intervention aimed at modifying type A behaviour was reported to successfully change not only emotional state but also to significantly lower the risk of subsequent heart attacks.¹⁶ Some healthcare professionals recommend that people at high risk for heart attacks who also have frequent feelings of impatience, lack of time, and hostility, seek counselling as a way to feel better and potentially reduce their risk of heart disease.

Researchers suggest that negative emotional states, such as hostility, distrust, anger,¹⁷ worry,¹⁸ and stress,¹⁹ promote heart attacks. Results from the National Heart, Lung, and Blood Institute (NHLBI) Family Heart Study showed that hostility was significantly associated with an increased risk of having a heart attack (in women) and increased odds of having heart surgery (in men), when a family history of heart disease was also present.^{20, 21} According to another study, women with a history of heart disease who report stressful relationships with their husbands or partners have almost triple the risk of suffering a heart attack, dying from heart disease, or requiring bypass surgery or angioplasty, compared with women in positive relationships.²²

Following a heart attack, bed rest is often recommended. However, a review of trials concluded that bed rest may actually worsen recovery from a heart attack.²³