Cardiorespiratory Fitness and Insulin Sensitivity Response to high-Intensity Interval Training in Overweight Postmenopausal Women

1.1. Background: It is known that physical exercise is an important non-pharmacological tool in the prevention and treatment of unwanted weight gain and diseases affecting post-menopausal women. High-intensity training is more efficient in improving glycemic control than low-intensity exercise and, interval protocol is better than continuous exercise to increase aerobic capacity. The objective of this study was to analyze the response of insulin resistance in postmenopausal women after 10 weeks of high-intensity interval training (HIIT). 1.2. Methods: 24 postmenopausal women (57 ± 7.8yrs) were submitted to a 10-wk HIIT protocol, performed at 70- 90% of maximum heart rate in treadmill. Blood pressure and heart rate were evaluated in every session. Level of physical activity and socio-demographic characterization were measured at baseline by the International Physical Activity Questionnaire (IPAQ-long-form version 8). Physical fitness (flexibility, handgrip, cardio respiratory fitness (VO2max)) and, fasting plasma glucose, insulin, triglycerides, total cholesterol were analyzed. Anthropometry of body weight, height and adiposity were taken. The chi-square (c2), ANOVA for variables with symmetrical distribution and model range for repeated measures with asymmetric distribution were applied for comparison between moments (M0-M1). The significance level adopted was 5%. 1.3. Results: The sample was composed by low-income women, elementary level of schooling, perception of good health and good level of physical activity, showing overweight and dyslipidemia. Baseline insulin resistance was 25%. After 10-week intervention there was a significant increase in aerobic fitness, moderate increase in flexibility and null in handgrip strength. The HIIT protocol reduced 50% of hyperglycemics (and hyperinsulinemics) but only 16.7% of the altered HOMA-IR. 1.4. Conclusions: The present protocol of HIIT was effective in improving cardio respiratory fitness and only moderately effective in improving insulin sensitivity, probably due to the maintenance of overweight and visceral adiposity.