VCBH COBRE Project Leader Sherrie Khadanga, MD had the results of her randomized clinical trial (RCT) examining high-intensity interval training (HIIT) for women in cardiac rehabilitation published online in JAMA Cardiology on November 24, 2021. “Optimizing Training Response for Women in Cardiac Rehabilitation” asked whether HIIT along with lower extremity resistance training (RT) is superior to standard moderate intensity training (MCT) for improving peak aerobic capacity (defined as peak oxygen uptake [peak Vo₂]) for women in cardiac rehab?

HIIT has been shown to be more effective in increasing peak Vo₂ compared MCT. However, benefits with HIIT for women are unclear because most studies of HIIT have included primarily men. Dr. Khadanga’s team hypothesized that increases in peak Vo₂ (L/min) would be greater among women performing HIIT and additional leg strength training compared with standard MCT.

Dr. Khadanga and her team conducted the RCT from July 2017 to February 2020. It included a total of 56 women (mean [SD] age, 65 [11] years; range 43-98 years) from a community-based cardiac rehabilitation program affiliated with a university hospital in Vermont. The HIIT group, or intervention group, exercised at 70% to 85% of peak heart rate (HR) with moderate intensive RT or HIIT (90% to 95% of peak HR) along with higher-intensity lower extremity RT 3 times per week over 12 weeks. Because baseline leg strength and intensity of exercise at session 36 were independent predictors of improvement of peak Vo₂, the results demonstrated that HIIT combined with intensive RT led to greater improvements in peak Vo₂. Although the study was not powered to test for safety of HIIT, it was well tolerated and warrants future surveillance.

Dr. Khadanga notes, “The combined use of high intensity interval training and intensive resistance training can provide significant improvement in exercise capacity for women. By conducting, what we believe is the first female-only study to examine the efficacy of HIIT and intensive RT in cardiac rehab as well as the use of directly measure peak Vo₂, we hope this combination can be incorporated in other cardiac rehabilitation programs.”