Many people are under the impression that if they have one or two of their risk factors for cardiovascular disease under control, then they have nothing to worry about. “If I don’t drink or smoke, then I can eat all the fast food I want, right?” Wrong. A recent study led by the Department of Clinical Epidemiology and Biostatistics at Örebro University in Sweden has found that even physically fit people who deal with a lot of stress run a higher risk for developing heart disease.

"Low-stress resilience in adolescence was associated with increased risk of coronary heart disease (CHD) in middle age and may diminish the benefit of physical fitness,” the research team said in a statement. "Our results further suggest that physical fitness varies by stress resilience level and that the protective effect of fitness in adolescence is reduced or eliminated in those with low-stress resilience. Effective CHD prevention might focus on promoting both physical fitness and tackling stress."

Researchers from Sweden and the UK analyzed data from 237,980 men born between 1954 and 1956, who were enrolled in the Swedish Military Conscription Register. During this time period in Sweden, conscription, also known as drafting, was mandatory for all male citizens between the age of 18 and 19. Each individual’s health, fitness, and psychological profiles were gauged using medical, psychiatric, and physical assessments from their conscription examination. Heart disease risk was assessed from 1987 — the year the Swedish National Patient Register received full coverage — to 2010.

Between 1987 and 2010, 10,581 men from the Swedish Military Conscription Register were diagnosed with heart disease. Men with low-stress resilience — the ability to cope with stress — tended to be at a higher risk for heart disease. This link between low-stress resilience and heart disease persisted even after researchers adjusted for physical fitness and other risk factors for heart disease. Although teenagers with low-stress resilience were rarely physically fit, teenagers with low-stress resilience who did have ideal physical fitness were not protected from heart disease.

According to the American Heart Association, stress, alcohol, diet, and nutrition are all considered contributing risk factors for a heart attack, meaning although there is an association between them and an increased risk for coronary heart disease, their significance and prevalence has not yet been determined. People looking to assess their risk for a heart attack or dying from coronary heart disease in the next 10 years should consider using the AHA’s Heart Attack Risk Calculator.

Source: Heart. 2015.