Patten, Rhiannon (2021) Effect of Exercise Interventions on Metabolic, Reproductive and Mental Health in Overweight Women with Polycystic Ovary Syndrome. PhD thesis, Victoria University.

Abstract

Polycystic ovary syndrome (PCOS) is a common and complex endocrinopathy with significant metabolic and reproductive manifestations, carrying a major health and economic burden. Exercise has consistently been found to improve clinical outcomes, but shortfalls with exercise prescription are evident, with little known about the impact of exercise intensity for improving health outcomes. Research suggests that high-intensity interval 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. Despite this, there is limited research exploring the efficacy of HIIT in comparison to standard moderate-intensity exercise recommendations for improving the health of women with PCOS. Therefore, the optimal exercise intensity for improving health outcomes remains unknown. The overall aim of this thesis was to determine the effectiveness of exercise, and more specifically exercise intensity, on the metabolic, reproductive and mental health and health-related quality of life of women with PCOS. The first two studies of my thesis were systematic reviews (Chapters 2 and 3), one that included a meta- analysis, to summarise and evaluate the current exercise intervention literature on key clinical metabolic, reproductive and anthropometric outcomes and on mental health and health-related quality of life (HRQoL) in women with PCOS. Briefly, results from these reviews suggested that exercise is beneficial for improving both the physical and mental health of women with PCOS. Furthermore, exercise of vigorous intensities provided additional benefits for increasing cardiorespiratory fitness, body composition and insulin resistance. There was insufficient evidence to be able to analyse the impact of exercise intensity on mental health and HRQoL, however, the available evidence indicated that exercise is effective for improving health-related quality of life and PCOS symptom distress. Exercise also shows some efficacy for improving symptoms and/or prevalence of depression and anxiety in women with PCOS. Following this, a protocol for a clinical trial was designed (Chapter 4), and conducted to investigate whether HIIT could confer greater benefits than standard moderate intensity continuous training (MICT) on cardio-metabolic outcomes (Chapter 5), reproductive outcomes (Chapter 6) and mental health and HRQoL (Chapter 7) in overweight women with PCOS. To do this, we employed a two-arm, randomised clinical trial where twenty-four overweight women, aged 18-45 years with diagnosed PCOS were randomised to either MICT (60-75% peak HR [HRpeak]) or HIIT (>90% HRpeak). We had 13 women complete the HIIT intervention and 11 women complete the MICT intervention. In regards to cardio-metabolic outcomes, both HIIT and MICT improved VO2peak (HIIT; 23.4 ± 10.1%, P <0.001 and MICT; 14.0 ± 9.3%, P <0.001), however, the HIIT group had a significantly greater improvement compared to MICT (P = 0.004). HIIT increased the insulin sensitivity index both compared to baseline (49.1 ± 38.2%; P = 0.014) and to MICT (P = 0.046). Overall, the improvement in VO2peak was associated with the improvement in insulin sensitivity (P = 0.003, R2 = 0.38). In terms of reproductive health outcomes, HIIT resulted in improvements in free androgen index (FAI) (P = 0.041), percent of free testosterone (0.016) and sex hormone binding globulin (SHBG) (0.026), with no significant changes as a result of MICT. HIIT also resulted in significantly greater improvements in SHBG (P = 0.005) and percent of free testosterone (P = 0.002) compared to MICT. A significant association between Δ insulin sensitivity and Δ free testosterone was detected in HIIT group (P = 0.029, adjusted R2 = 0.43), but not in the MICT group. In regards to menstrual cyclicity, although not significant, 69% of participants (9 of 13) and 18.2% (2 of 11) reported improvements in menstrual cyclicity following HIIT and MICT, respectively. When examining psychosocial outcomes, reductions in depression (P <0.001) and stress (P = 0.005) scores were observed in the HIIT group. Anxiety scores were reduced in both groups (HIIT; P = <0.001, and MICT; P = 0.007), however, there was a significantly greater reduction following HIIT compared to MICT (P = 0.017). The HIIT group also significantly improved emotions, weight and menstrual problem domains of the polycystic ovary syndrome questionnaire (PCOSQ) and physical functioning, role emotional, energy and general health domains of the SF-36. In conclusion, supervised HIIT is effective and offers greater improvements in aerobic capacity, insulin sensitivity, hormonal profiles and anxiety scores in comparison to MICT in overweight women with PCOS. We also demonstrated that HIIT is efficacious for improving menstrual cyclicity, depression and HRQoL, indicating that HIIT may be superior to MICT for improving a wide range of health outcomes in women with PCOS. Therefore, HIIT should be considered as an effective strategy to promote health, reduce the cardio-metabolic risk and improve key clinical outcomes in this population.

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