High-Intensity Interval Training in Polycystic Ovary Syndrome: A Two-Center, Three-Armed Randomized Controlled Trial.

PURPOSE: Exercise training is recommended to improve cardiometabolic health and fertility in women with polycystic ovary syndrome (PCOS), yet there are few randomized controlled trials on the effects of different exercise protocols on clinical reproductive outcomes. Our aim was to determine the effect of high-intensity interval training (HIT) on menstrual frequency, as a proxy of reproductive function, in women with PCOS. METHODS: The IMPROV-IT study was a two-center randomized controlled trial undertaken in Norway and Australia. Women with PCOS were eligible for inclusion. After stratification for body mass index <27 or ≥27 kg·m-2 and study center, participants were randomly allocated (1:1:1) to high-volume HIT (HV-HIT), low-volume HIT (LV-HIT), or a control group. Measurements were assessed at baseline, after the 16-wk exercise intervention, and at 12-month follow-up. The primary outcome was menstrual frequency after 12 months. Secondary outcomes included markers of cardiometabolic and reproductive health, quality of life, and adherence to and enjoyment of HIT. RESULTS: We randomly allocated 64 participants to the HV-HIT (n = 20), LV-HIT (n = 21), or control group (n = 23). There were no differences in menstrual frequency at 12 months between the LV-HIT and control groups (frequency ratio, 1.02; 95% confidence interval [CI], 0.73-1.42), the HV-HIT and control groups (frequency ratio, 0.93; 95% CI, 0.67-1.29), or the LV-HIT and HV-HIT groups (frequency ratio, 1.09; 95% CI, 0.77-1.56). Menstrual frequency increased in all groups from baseline to 12 months. More participants became pregnant in the LV-HIT group (n = 5) than in the control group (n = 0, P = 0.02). CONCLUSIONS: A semisupervised HIT intervention did not increase menstrual frequency in women with PCOS.Clinical Trial Registration Number:ClinicalTrials.gov (NCT02419482).

Circulating and Adipose Tissue miRNAs in Women With Polycystic Ovary Syndrome and Responses to High-Intensity Interval Training.

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression post-transcriptionally. In women with polycystic ovary syndrome (PCOS), several miRNAs are differentially expressed compared to women without PCOS, suggesting a role for miRNAs in PCOS pathophysiology. Exercise training modulates miRNA abundance and is primary lifestyle intervention for women with PCOS. Accordingly, we measured the expression of eight circulating miRNAs selected a priori along with miRNA expression from gluteal and abdominal adipose tissue (AT) in 12 women with PCOS and 12 women matched for age and body mass index without PCOS. We also determined the miRNA expression "signatures" before and after high-intensity interval training (HIT) in 42 women with PCOS randomized to either: (1) low-volume HIT (LV-HIT, 10 × 1 min work bouts at maximal, sustainable intensity, n = 13); (2) high-volume HIT (HV-HIT, 4 × 4 min work bouts reaching 90-95% of maximal heart rate, n = 14); or (3) non-exercise control (Non-Ex, n = 15). Both HIT groups trained three times/week for 16 weeks. miRNAs were extracted from plasma, gluteal and abdominal AT, and quantified via a customized plate array containing eight miRNAs associated with PCOS and/or exercise training responses. Basal expression of circulating miRNA-27b (c-miR-27b), implicated in fatty acid metabolism, adipocyte differentiation and inflammation, was 1.8-fold higher in women with compared to without PCOS (P = 0.006) despite no difference in gluteal or abdominal AT miR-27b expression. Only the HV-HIT protocol increased peak oxygen uptake (VO2peak L/min; 9%, P = 0.008). There were no changes in body composition. In LV-HIT, but not HV-HIT, the expression of c-miR-27b decreased (0.5-fold, P = 0.007). None of the remaining seven circulating miRNAs changed in LV-HIT, nor was the expression of gluteal or abdominal AT miRNAs altered. Despite increased cardiorespiratory fitness, HV-HIT did not alter the expression of any circulating, gluteal or abdominal AT miRNAs. We conclude that women with PCOS have a higher basal expression of c-miR-27b compared to women without PCOS and that 16 weeks of LV-HIT reduces the expression of this miRNA in women with PCOS. Intense exercise training had little effect on the abundance of the selected miRNAs within subcutaneous AT depots in women with PCOS.

The relationship between maximum heart rate in a cardiorespiratory fitness test and in a maximum heart rate test.

OBJECTIVES: It is suggested that individuals will not reach their heart rate maximum (HRmax) at an incremental cardiorespiratory fitness (CRF) test and commonly five beats per minute (bpm) are added to the highest heart rate (HR) reached. To our knowledge, there is not sufficient data justifying such estimation. Our aim was to assess whether individuals reached HRmax in an incremental CRF test to exhaustion. DESIGN AND METHODS: Fifty-one males and 57 females (aged 22-70 years) completed both an incremental CRF test (gradual increase in speed and/or inclination until volitional exhaustion) and a test designed to reach HRmax (with repeated work bouts at high intensity before maximal exertion) ≥48h apart. We investigated the relationship between the highest HR in the two tests using hierarchical linear regression analysis, with HRmax from the HRmax test as a dependent variable, and the highest HR reached at the CRF test (HRcrf), whether maximum oxygen uptake was reached on the CRF test, CRF, sex and age as independent variables. RESULTS: HRmax was 2.2 (95% confidence interval, 1.5-2.9) bpm higher in the test designed to reach HRmax than in the CRF test (p<0.001). Only HRcrf significantly predicted HRmax, with no contribution of the other variables in the model. HRmax was predicted from the highest HR reached in an incremental CRF test by multiplying HRcrf with 0.967, and adding 8.197 (HRmax=8.197+[0.967×HRcrf]) beats/min. CONCLUSION: Non-athletes reached close to HRmax in a standard CRF test.