The Effects of a 16‐week Combined Exercise Training on Obesity and Physical Fitness in Breast Cancer Survivors: A Randomized Controlled Trial
Authors: Lee Kyuwan 
Published: November 2023

IntroductionBreast cancer survivors are at an elevated risk for the development of comorbid conditions such as obesity, diabetes, and cardiovascular disease, despite the improved survival rate from breast cancer. Obesity is associated with worse breast cancer‐specific survival and poorer prognosis of breast cancer (i.e. more aggressive disease at diagnosis and higher probability of recurrence and mortality) compared to non‐obese patients. It is well established that obesity‐related comorbidities are exacerbated by physical inactivity which can be improved by regular participation in exercise.The purpose of this study was to examine the effects of a 16‐week combined aerobic and resistance training intervention on obesity‐related parameters and physical fitness in breast cancer survivors. Further, we examined whether changes in obesity‐related parameters were correlated with improved physical fitness.MethodsFifty‐six participants were recruited from the USC and Los Angeles County Hospitals. Participants were randomized to either the Control (CON; n=28) or the Exercise (EX; n=28) groups. The EX group participated in supervised aerobic and resistance exercise sessions 3 times a week for 16 weeks at the USC. Aerobic exercise was performed at 65–85% heart rate maximum. Resistance exercises were performed with 3 sets of 10–15 repetitions at 65–70% 1‐repetition maximum. The CON group was asked to maintain less than 120 min/week of exercise during the study period. Obesity‐related parameters (body mass index (BMI), body weight, waist circumference, waist/hip ratio, body fat percentage) and physical fitness (estimated VO2max) were assessed before after the 16‐week intervention. Repeated measure ANOVA was used to examine the effects of exercise training on parameters of obesity and physical fitness between the 2 groups. Pearsons correlation was used to examine the relationship between various measurements of obesity and estimated VO2max.ResultsThe EX group exhibited significant improvements in BMI, waist circumference, waist/hip ratio, and estimated VO2max following the 16‐week intervention when compared to the CON group (P<0.05). Body weight and body fat percentage did not significantly improve in the EX group (P>0.05). Following the intervention, there was a significant correlation between VO2max and waist circumference (P=0.05, r=−0.27). Estimated VO2max was not correlated with total body fat percentage, BMI, and body weight.ConclusionThe results of this study show that there is a significant effect of combined exercise training on physical fitness and some obesity‐related parameters in breast cancer survivors. Additionally, waist circumference is significantly correlated with estimated VO2max following exercise intervention. These finding may suggest that combined exercise training has a beneficial effect on obesity which is correlated with improved physical fitness.Support or Funding InformationThis trial is funded by the National Cancer Institute (NCI) of the NIH K07 (CA16071908).