Effects of an Indoor Cycling Program on Cardio-Metabolic Factors in Women With Obesity and Normal Body Weight

Plain-language summary

The aim of the research is to (1) evaluate the potential clinical effectiveness and biological mechanisms of indoor cycling in the treatment of obesity and (2) provide-up-to-date evidence on the impact of indoor cycling in reducing cardiovascular disease (CVD) risk factors, namely, hypertension, dyslipidemia, type 2 diabetes, endothelial dysfunction. We hypothesize that IC training, can be a good stimulus to mitigate cardiovascular risk factors in women with obesity and to improve values of the examined indicators towards that occurring in women with normal body weight. The study was designed as a prospective exercise intervention trial. The study involved women with obesity (OW) and women with normal body weight (NW). Both study groups underwent the same 3-month physical training program. Outside the implemented program, all participants were instructed to maintain their normal physical activity, diet and not to use any dietary supplements. Dietary intake was assessed using interviews conducted at baseline and after completion of the trial. The amount of nutrients in participant's daily diet was processed and evaluated using a dietetics computer program. The intake of nutrients, total caloric intake during the study were constant in both groups. Anthropometric parameters, blood pressure and physical capacity were measured and blood samples were taken at baseline and after completion of the physical training program. The study involved 31 obese or normal weight women aged 34-62. A total of 23 women with obesity (body mass index (BMI) ≥ 30 kg/m2; waist circumference \> 80 cm) registered and screened from among 163 women at the outpatient clinic of the Department of Internal Medicine, Metabolic Disorders, and Hypertension, University of Medical Sciences, Poznań, Poland were enrolled to OW group. The NW group consisted of 8 healthy women from the announcement (BMI ≤ 24.9 and ≥ 18.5 kg/m2). Informed consent was obtained from all participants, and the study was approved by the Ethics Committee of Poznan University of Medical Sciences (case no. 1077/12; supplement no. 753/13). The study conformed to all ethical issues included in the Helsinki Declaration. The 3-month intervention consisted of a physical exercise program involving three indoor cycling sessions per week, with a total of 36 training sessions. Subjects exercised on cycle ergometers Schwinn® Evolution® (Schwinn Bicycle Company, Boulder, Colorado, USA). Each session lasted approximately 55 minutes. Training sessions consisted of a 5-min low-intensity warm-up (cycling at 50-65% of maximum heart rate (HRmax)), 40 min of main training at an intensity of 65-95% of HRmax, 5 min of non-weight-bearing cycling, finishing with 5 min of low-intensity cool-down stretching and breathing exercises. Main part of the training was interval. Each exercise session consisted of 3 to 4 high intensity intervals with intensity exceeding 80% of HRmax, often reaching anaerobic threshold. High intensity intervals lasted approximately 4-minutes and were interspersed by recovery periods at 65-80% of HRmax. HR during sessions was monitored with a Suunto Fitness Solution® device (Suunto, Vantaa, Finland). To ensure that assigned exercise intensities were obtained, the average per cent of the maximum heart rate during the entire training session was obtained from the device Blood samples for biochemical analyses were taken from a basilic vein, after overnight 12-hour fasting. In the serum samples, parameters were measured using commercially available enzyme-linked immunoassays. Both before and after the whole training programme, the following measurements were made: body weight and height, BMI, waist and hip circumference, WHR, body composition (DXA), total-body skeletal muscle mass index, graded exercise test, isokinetic muscle strength of knee flexors and extensors, exercise and resting blood pressure, and the heart rate. Vascular endothelial function indices (eNOS, VEGF, TBARS and TAS) as well as TCH, LDL-C, HDL-C, TG, oxLDL and CRP of venous blood were determined. A sample size was determined according to changes in VO2 peak. A total of 6 subjects in OW group and 7 subjects in NW group was calculated to yield at least 80% power of detecting an intervention effect as statistically significant at the 0.05 α level.

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