Effects of an Indoor Cycling Program on Cardio-Metabolic Factors in Women With Obesity and Normal Body Weight
Effects of an Indoor Cycling Program on Cardio-Metabolic Factors in Women With Obesity and Normal Body Weight
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.
Anthropometric measurements were conducted with the subjects wearing light clothing and no
 shoes. Weight was measured to the nearest 0.1 kg and height to the nearest 0.5 cm. BMI was
 calculated as weight divided by height squared (kg/m2 ). Obesity was defined as BMI ≥ 30
 kg/m2. Waist circumference (cm) was measured at the level of the iliac crest at the end of
 normal expiration. Hip circumference was measured at the maximum protuberance of the
 buttocks. Waist and hip circumferences were measured to the nearest 0.5 cm. Waist-to-hip
 ratio (WHR) was calculated as waist circumference divided by hip circumference. Index of
 central obesity (ICO) was calculated as waist circumference (cm) divided by height (cm)
 (Parikh, et al., 2012).

 Body composition analysis was assessed using DXA (GE Healthcare Lunar Prodigy Advance; GE
 Medical Systems, Milan, Italy). The subjects were instructed not to make any intense physical
 effort in the 24h prior to the examination. The subjects were given complete instructions on
 the examination procedure. They wore cotton T-shirt, shorts, and socks and lay on the DXA
 table supine and motionlessly during the testing procedure. They were instructed to remove
 all metal, rubber, and plastic objects that might affect the X-ray beam. The same
 well-trained laboratory technician positioned the subjects, performed the scans, and executed
 the analysis according to the operator's manual, using the standard analysis protocol. Total
 body fat mass and lean body mass were determined using standard scan mode (in case of
 moderately obese subjects) or thick scan mode (in case of extremely obese subjects); the
 absorbed dose of radiation was 0.4 μGy and 0.8 μGy, respectively.

 To determine the subjects' physical capacity, a Graded Exercise Test (GXT) was performed on
 an electronically braked cycle ergometer (Kettler ® DX1 Pro, Kettler, Ense, Germany). GXT
 began at a work rate of 25 W (60 rev/min). The work rate was incremented by 25 W every 2 min
 until the subject could no longer maintain the required pedal cadence. Each test lasted
 4-14.5 min, depending on age and aerobic fitness status. The exercise tests were conducted
 between 8: 00 and 12: 00 a.m. in an air-conditioned laboratory, 2 h after consuming a light
 breakfast. Expired gases, minute ventilations (Ve), and heart rate (HR) during GXT were
 monitored continuously with an automated system (Oxycon Mobile ® ; Viasys Healthcare,
 Hoechberg, Germany). Oxygen intake (VO 2 ) and carbon dioxide output (VCO 2 ) was measured
 breath-by-breath and averaged over 15-second periods. Before each trial, the system was
 calibrated according to the manufacturer's instructions. Peak VO2 was defined as the highest
 15-second averaged VO 2 obtained during the final exercise load on the test. HR peak (bpm)
 was measured as the highest 15-second average value in the test. To determine ventilatory
 threshold (VT), the V-slope method was administered using computerized regression analysis on
 the slopes of the CO 2 output versus O2 uptake plot, which detects the beginning of the
 excess CO 2 output generated from the buffering of H +. The method involves analyzing the
 behavior of VCO 2 as a function of VO 2 during GXT with a consequent increase in VCO 2 . This
 results in a transition in the relationship between VCO 2 and VO 2 . The software supplied by
 Viasys Healthcare was used, supported with a visual inspection on the part of an experienced
 researcher. As a secondary method, the ventilatory equivalent method (VEQ method) was
 employed and the point at which the equivalent for oxygen (VE/VO 2 ) increased without a
 concomitant rise in the equivalent for carbon dioxide (VE/VCO 2 ) was detected. The VT was
 expressed as a heart rate (HR VT ).

 Exercise blood pressure was measured during a GXT using a digital electronic tensiometer
 (model 705IT TM, Omron Corporation, Kyoto, Japan). The measurement was taken during maximal
 work rate. Exercise HR was measured as the highest 15-second average value in the GXT.
 Resting blood pressure was measured fasting in the morning hours, in a sitting position with
 the legs uncrossed and the back and arm supported. Resting HR was measured under the same
 conditions, using auscultation of the heart by stethoscope. Regular or large adult cuffs were
 used, depending on the patient's arm circumference.
Inclusion Criteria:

 Initial inclusion criteria for both study groups were as follows: age: 30 to 65 years and
 stable body weight in the month prior to the trial (permissible deviation ± 1 kg).

 For Women with Obesity Group: BMI ≥ 30 kg/m2; waist circumference > 80 cm. For
 Normal-weight Womeng Group: BMI ≤ 24.9 and ≥ 18.5 kg/m2

 Exclusion Criteria for both study groups were as follows:

 -  secondary form of obesity and/or secondary form of hypertension;

 -  diabetes mellitus;

 -  history of coronary artery disease;

 -  stroke;

 -  congestive heart failure;

 -  clinically significant arrhythmias or conduction disorders;

 -  malignancy;

 -  poorly controlled hypertension (SBP > 140 mmHg and/or DBP > 90 mmHg), and/or
 modifications to antihypertensive treatment;

 -  lipid disorders requiring the implementation of drug treatment;

 -  clinically significant abnormalities in liver, kidney or thyroid gland function;

 -  clinically significant acute or chronic inflammatory process within the respiratory,
 digestive or genitourinary tracts, or the oral cavity, pharynx or paranasal sinuses;
 or, presence of connective tissue disease or arthritis;

 -  history of infection within the month prior to the study;

 -  nicotine, alcohol or drug abuse;

 -  and / or any other condition which, according to the researchers, would cause that
 participation would be detrimental to the participant or would prevent, limit or
 interfere with the results of the study.