Lack of physical activity is the biggest risk factor for heart disease in women older than 30 years old, according to a recent study BBC News reported.

Researchers from the University of Queensland in Australia found that lack of exercise exerts a greater impact on a women's lifetime risk of developing heart disease than other well-known risk factors, including overweight.

They wanted to quantify the changing contribution made to a woman's likelihood of developing heart disease across her lifetime for each of the known top four risk factors in Australia: excess weight; smoking; high blood pressure; and physical inactivity in the study.

"Together, these four risk factors account for over half the global prevalence of heart disease, which remains the leading cause of death in high income countries," researchers said in a statement.

For the study, researchers looked at the population attributable risk - a mathematical formula used to define the proportion of disease in a defined population that would disappear if exposure to a specific risk factor were to be eliminated.

They based their calculations on estimates of the prevalence of the four risk factors among 32,154 participants in the Australian Longitudinal Study on Women's Health, which has been tracking the long term health of women born in 1921-6, 1946-51, and 1973-8, since 1996.

Based on the findings, the prevalence of smoking fell from 28 percent in women age 22-27 to 5 percent in 73-78 year olds. But the prevalence of inactivity and high blood pressure increased steadily across the lifespan from age 22 to 90. Overweight increased from age 22 to 64, and then declined in older age.

"Our data suggest that national programs 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," researchers concluded in their study.

Researchers estimate that if every woman between the ages of 30 and 90 were able to reach the recommended weekly exercise quota -- 150 minutes of at least moderate intensity physical activity -- then the lives of more than 2000 middle aged and older women could be saved each year in Australia alone.