Exercise can reduce the side effects of drugs used to reduce the risk of breast cancer recurrence, say researchers.

The findings of a new study show that side effects of hormone therapy drugs may be alleviated through a combination of weight training and moderate aerobic exercise.

Breast cancers are hormone receptor-positive, using estrogen or progesterone to grow and spread. Breast cancer survivors often use hormone therapy drugs, such as Aromatase Inhibitors (AIs) to control recurrence of the disease.

However, these may cause side effects including severe joint pain and bone loss. Side effects may worsen particularly in obese or overweight patients. About 40% of breast cancer survivors stop taking these drugs long before the usual five-year treatment plan.

“These changes put women at risk for frailty fractures and osteoporosis, not to mention further risk for comorbid chronic disease and cancer reoccurrence,” said Gwendolyn Thomas, assistant professor at Syracuse University, New York.

Interventions that address obesity in women taking AIs can help them continue this necessary treatment, reported the researchers.

The research focused on the effects of aerobic and resistance exercise in post-menopausal survivors, taking AIs.

Participants of the study did two sessions of weight training along with 150 minutes of moderate aerobic activity, such as brisk walking or jogging, every week for a year. The study recorded their body composition, including body mass index, body fat, and lean body mass.

“We noticed a drop in body fat and body mass index, as well as a significant increase in their lean body mass,” said Thomas.”These changes have clinical benefits, but also suggest that exercise should be prescribed in conjunction with AIs, as part of a regular treatment regimen.”

Findings of the study were published in the Obesity Journal.