Efficacy of High-Intensity Intermittent Training for Improving Cardio-Metabolic Health in Women With Polycystic Ovary Syndrome

Abstract Polycystic ovary syndrome (PCOS) is a common and complex endocrinopathy with significant metabolic and reproductive manifestations, carrying a major health and economic burden. Consistent improvements in clinical outcomes have been reported as a result of exercise training, but shortfalls with exercise prescription are evident. Research suggests that high-intensity intermittent training (HIIT) is feasible, well tolerated and enjoyable for people with or at risk of chronic disease and can address many of the shortfalls and barriers to exercise participation. To investigate the effects of high-intensity exercise on cardio-metabolic health, twenty-four reproductive aged, overweight or obese, sedentary women with PCOS were recruited from the community and randomised to complete either 12 weeks of moderate intensity continuous cycling training (MICT; 60–65% of maximal heart rate [HRmax]; n=11) or HIIT (90–100% HRmax; n=13). All exercise was supervised by an exercise physiologist and completed 3 times per week on a cycle ergometer. Baseline and post-testing measures consisted of peak oxygen consumption (VO2peak) determined by a graded maximal exercise test, body composition by DXA scan and insulin sensitivity determined by euglycaemic-hyperinsulinaemic clamp. Significant improvements in VO2peak were seen after both HIIT (P <0.001) and MICT (P <0.013) with a significant between-group interaction favouring HIIT (P = 0.014). The insulin sensitivity index significantly improved after HIIT (P = 0.009) with no changes observed after MICT (P = 0.860), also resulting in a significant between-group difference favouring HIIT (P = 0.046). No changes were observed for body weight, BMI or fat mass, however, there was a significant increase in percentage of lean mass after HIIT (P = 0.026). The present study is the first to compare current exercise recommendations of moderate and vigorous intensities in women with PCOS. The results of this study provide preliminary validation of HIIT, suggesting that vigorous intensity exercise should be considered in order to improve cardio-metabolic health in women with PCOS.