Effect of Two Physical Training Programs on Oxygen Uptake and Heart Rate On-kinetics in Patients COPD

Overview

Patients with chronic obstructive pulmonary disease (COPD) present slowed pulmonary oxygen uptake (VO2) and heart rate (HR) kinetics compared with age-matched controls. Patients with COPD present significant loss of body mass, decreased strength and endurance of respiratory muscles and lower limbs, leading reduced exercise capacity. This reduced exercise capacity can be marked by slowed kinetics of VO2 and HR at the onset of heavy-intensity exercise. Additionally, derangements in the diffusive and convective transport of oxygen to skeletal muscle mitocondria, and intramyocyte metabolic machinery, higher ventilation and disturbances in mechanics of breathing, hypoxemia, pulmonary hemodynamics, autonomic balance, and peripheral vasodilation, and accumulation of by-products that might be related to increased muscle fatigability could slow the response of systemic (central) and peripheral (microvascular) oxygen delivery to a point where the kinetics of VO2 might become limited by O2 availability and HR. Thus, the physical training programs of the lower limbs, in addition to presenting scientific evidence "A", are important components, resulting in the reversal of the manifestations of COPD, resulting in improvement in exercise capacity, well significantly speeded VO2 and HR kinetics in patients with COPD. However, it should be taken into account the choice of an appropriate program limitations and severity of disease. Assuming that COPD patients present slower VO2 and HR kinetics, the investigators hypothesized that the heavy-intense interval physical training in equipament elliptical would promote a greater increase in the functionality (functional performance) and speeded kinetics in the cycle ergometer and elliptical equipment constant-load intense exercises tests of COPD patients. In this context, the present study intends to evaluate and compare the effects of resistive plus aerobic physical training and interval physical training on oxygen consumption (VO2) and heart rate (HR) kinetics responses at the onset in cycle ergometer and elliptical equipment constant-load intense exercises tests in patients with COPD.

Subjects performed after and before of two physical training program the following tests: lung function test,cardiopulmonary exercise testing (CPT), constant-load exercise test in cycle ergometer, Constant-load exercise test in elliptical equipament, one repetition maximum test(1RM), on alternate days. * Lung function: All patients underwent spirometry with the determination of FEV1 and FVC according to American Thoracic Society recommendations. Spirometry was performed using a COSMED microQuark PC - based Spirometer ®, (Pavona di Albano - Roma, Itália), which was calibrated before each test. * Cardiopulmonary Exercise Testing (CPT): Incremental symptom-limited exercise testing was performed on a cycle-ergometer(Ergo FIT®, model Ergo 167 Cycle, Pirmasens, Germany) using a computer-based ventilatory expired gas analysis system (VO2000, Medgraphics Corp., St. Paul, MN). All subjects underwent a CPT to determine the peak work rate and the peak oxygen uptake (peak VO2). The subjects' electrocardiographic recordings were monitored using a cardiac monitor, SpO2, BP and sensation of dyspnea and fatigue using the BE-CR-10. A gas analyzer (VO2000 Medgraphics®, St Paul MN, USA) was used to obtain the participants' VO2 at each stage of the test. The ergospirometric values were recorded by the mean value measured every three breaths using the Aerograph® program. The VO2 was determined choosing the higher and more coherent value in the final 30 seconds of each stage. * Constant-load exercise test in cycle ergometer and Constant-load exercise test in elliptical equipament: The two exercise tests were performed at 70% of the previously determined work rate in CPT. During the CSET, VO2 was measured breath-by-breath and averaged every three respiration, while SpO2, HR, and the electrocardiogram were continuously monitored, and calculated a on-Kinetics of VO2 and HR. \* Physical training program: * The interval physical training on the elliptical trainer (Kiko's® HM 6022, São Paulo, SP, Brazil) totalized 18 sessions that the individuals of both groups had to attend at least twice a week. Each session lasted not more than 60 minutes and they were all individual meetings. The minimal work rate of the equipment was 40W and the lower increment work rate was 10W. The elliptical trainer allowed combined exercise with the upper limb, however, in the present study, the exercise was performed with the arms fixed, and every participant's HR was monitored using a pulse frequency meter (Polar® FS2cTM Kempele, Finland), the pulse oxygen saturation (SpO2) using a pulse oximeter (Nonin®, model 8500A, Minneapolis, Mn, USA), the blood pressure (BP) using a mercury sphygmomanometer (Oxigel®, São Paulo, SP, Brazil) and the sensation of dyspnea and lower limb fatigue using the Modified Borg CR-10 Scale (BE-CR10). The elliptical exercise was an interval training and was based on studies that performed interval training exercise in cycle ergometer. This was a 30-minute exercise with a rest interval established in one minute. The exercise's work rateworkload was the maximal achieved in the CPT, and it was not modified until the sessions were finished The individuals who did not reach 40W in the CPT performed 30 seconds exercising periods at 40W with 1-minute resting interval. The volunteers who achieved workload equal or higher 40W performed 1-minute exercising periods at the workload achieved in the CPT with 1-minute resting interval. During the exercise on the equipment, the individuals should keep the speed between 40 and 50 rpm.Vital signs (HR, BP, SpO2) were recorded at the beginning and at the end of each session, as well as monitored before, during and after the elliptical exercise. During the training, the vital signs were recorded on the first 30 seconds of each resting interval. * The aerobic associate resisted physical training consisted of thirty minutes oa aerobic training at 60-70% of work rate obtained in CPT and subsequently three sets of fifteen repetitions of resistance training in lower limbs on leg press with an intensity of 40-60% of one repetition maximum test.