A lack of exercise puts younger women at far greater risk of heart attacks than smoking or being obese, a major study has found.
Researchers found inactive women in their 30s are almost 50% more likely to develop heart disease in their lifetime than those who are fit.
Now the team has called on governments to launch public health campaigns on the importance of exercise, arguing it would have a far greater impact on reducing heart disease deaths than drives to discourage smoking or promote healthy eating.
The scientists looked at the records of 32,541 women aged 22 to 90, including details about lifestyle and whether they had heart disease.
Armed with this data, they used a mathematical formula to work out their risk of heart disease during their lifetime based on whether they were inactive, were smokers, had high blood pressure or were obese.
A lack of exercise was found to pose the greatest risk to women across all age groups.
Those in their early 30s who were classed as inactive were nearly 50% more likely to suffer from the condition in their lifetime than active women.
The risk decreased slightly with age. Inactive women in their late 40s were 38% more at risk, falling to 28% in the late 50s.
By comparison, the risk was 40% for women smokers in their 30s and 30% for the obese. Although obesity and being unfit are closely linked, the researchers from the University of Queensland pointed out that many slim women are inactive.
The latest UK figures show a quarter of women are classified as inactive, while just over half do the recommended two and a half hours of physical activity a week.
Heart disease, which includes heart attacks and strokes, is by far the biggest killer in Britain, claiming 82,000 lives a year.
Experts have previously claimed that exercising can halve the risk of getting the condition because it lowers the blood pressure, reduces cholesterol which blocks arteries, and improves circulation.
Lead researcher Professor Wendy Brown described inactivity as the ‘Cinderella risk factor’ for heart disease;
‘Our data suggests that national programmes for the promotion and maintenance of physical activity across the adult lifespan, but especially in young adulthood, deserve to be a much higher public health priority for women than they are now.’
The study, published in the British Journal of Sports Medicine, concluded: ‘Continuing efforts to reduce smoking rates in young adult women are warranted.
‘However, from about age 30, the population attributable risk for inactivity outweighs that of the other leading risk factors, including high BMI, which is currently receiving much more attention.’
Thembi Nkala, senior cardiac nurse at the British Heart Foundation, said:
‘We already know physical inactivity is a major risk factor for heart disease.
Interestingly, this study shows its dominant influence on heart disease amongst women, and suggests a greater need to promote regular physical activity.’
She added: ‘It is important to remember that heart disease is linked to other factors such as smoking, obesity, high blood pressure and high cholesterol.’