A new study suggests that working out can reduce the influence of genes on obese women over the age of 70.

The study, published in the journal Menopause, revealed that genetic associations on body mass index (BMI) were strongest in sedentary postmenopausal women and weakest in women who reported high levels of recreational physical activity. "Our sample, which included older women, is the first to show that in the 70 to 79-year-old age group, exercise can mitigate the genetic effects of obesity," said lead author Heather Ochs-Balcom, Associate Professor at the University at Buffalo's School of Public Health and Health Professions.

"The message here is that your genetic risk for obesity is not wholly deterministic. The choices we make in our life play a large role in our health," Ochs-Balcom added. For the study, the researchers studied 8,206 women who participated in the Women's Health Initiative. They used a larger set of 95 genetic polymorphisms to construct their body mass index genetic risk score to study the interaction between physical activity and obesity.

Then the researchers evaluated whether genetic associations were modified by exercise and age. "Our work suggests that in older age, we can overcome our destiny for obesity--given to us by our parents--through exercise," Ochs-Balcom said. The study is significant in that, up to this point, little had been known about the effect of obesity genes later in life, particularly whether genetic predisposition can be mitigated by healthy behaviours such as physical activity, the researchers noted.