Biomedical subjects

Attila Somfay

Publications and source records attributed to Attila Somfay.

6 recordsLinked to original sources

PubMed2005

[The effect of controlled and uncontrolled dynamic lower extremity training in the rehabilitation of patients with chronic obstructive pulmonary disease].

UNLABELLED: Pulmonary rehabilitation has become a part of the integrated management of patients with chronic obstructive pulmonary disease (COPD). The lower extremity dynamic training has been proved to be the most effective element of the program. OBJECTIVE: Does the supervised training have more favorable effect in case of similar program? PATIENTS AND METHODS: In two groups: 54 patients, supervised (group K, n = 22) and not supervised (group NK, n = 32) by physiotherapists, chosen at random have been investigated. Both groups consisted of hospitalized patients of the same severity (forced expiratory volume in one second) [FEV1 (average +/- SD)]: K: 51.0 +/- 16.1 vs. NK: 51.9 +/- 15.6% pred). Group K performed physiotherapist-supervised cycling training in the Pulmonology Ambulance Unit 3-4 times a week for 45 minutes doing an 8-week period and group NK performed training in the form of cycling, stepping on stairs or dynamic walking at home with the same duration, weekly periodicity and time interval. RESULTS: After rehabilitation vital capacity (VC) (K: 3.0 +/- 0.8 vs. 3.3 +/- 0.7 l, p < 0.05), emphysema ratio (RV/TLC): K: 53.5 +/- 10.1 vs. 51.6 +/- 9.9, p < 0.05) in the supervised group, and alveolar volume (VA) in the not supervised group (NK: 4.3 +/- 0.9 vs. 4.7 +/- 0.9 l, p < 0.05) significantly improved. Improvement of exercise capacity was more effective in group K (K: 92.7 +/- 33.9 vs. 106.4 +/- 34.5 W, p < 0.001; NK: 95.8 +/- 36.7 vs. 99.9 +/- 35.1 W, p < 0.05). In both groups aerobic capacity (VO2: K: 1.2 +/- 0.4 vs. 1.3 +/- 0.4 l/min, p < 0.01, NK: 1.1 +/- 0.4 vs. 1.2 +/- 0.4 l/min, p < 0.01; VO2/kg: K: 16.1 +/- 5.5 vs. 17.5 +/- 5.8 ml/kg/mm, p < 0.01, NK: 16.2 +/- 5.3 vs. 16.7 +/- 4.8 ml/kg/ min, p < 0.01) and anaerobic threshold level [AT (pred VO2%)] (K: 36.6 +/- 9.8 vs. 42.8 +/- 10.2%, p < 0.001; NK: 40.8 +/- 12.0 vs. 44.6 + 11.6%, p < 0.001) significantly improved. Heart rate reserve: (K: 17.7 +/- 22.7 vs. 28.8 +/- 31.5 l/min, p < 0.01; NK: 20.4 +/- 21.2 vs. 25.0 +/- 21.6 l/min, p < 0.01) improved at the same level of exercise. The Borg scale of dyspnea (0-10): (K: 6.4 +/- 2.5 vs. 5.7 +/- 2.7, p < 0.05; NK: 7.5 +/- 1.8 vs. 6.9 +/- 2.2, p < 0.05) was reduced and quality of life score (0-24): K: 11.5 +/- 0.7 vs. 9.0 +/- 2.8, p < 0.005; NK: 11.6 +/- 2.3 vs. 7.0 +/- 1.9, p < 0.005) was improved. CONCLUSION: In both group dynamic lower extremity training caused improvement in exercise capacity. The favorable metabolic effect of training was shown by the change of anaerobic threshold resulting in less carbon dioxide production during analogous exercise. This reduction led to less ventilation reducing the work of breathing in supervised group. The more favorable adaptation taking place in the group supervised by physiotherapists might have resulted from the controlled higher intensity of the training.

Adult↗

PubMed2005

Exercise training decreases ventilatory requirements and exercise-induced hyperinflation at submaximal intensities in patients with COPD.

STUDY OBJECTIVES: We hypothesized that endurance exercise training would reduce the degree of hyperinflation for a given level of exercise and thereby improve submaximal exercise endurance. METHODS: Twenty-four patients with COPD (mean FEV(1), 36.4 +/- 8.5% of predicted [+/- SD]) undertook a high-intensity cycle ergometer exercise training program for 45 min, three times a week for 7 weeks. Before and after training, the patients performed both an incremental exercise test to maximum and a constant work rate (CWR) test on a cycle ergometer at 75% of the peak work rate obtained in the pretraining incremental test. Ventilatory variables were measured breath-by-breath, and inspiratory capacity (IC) was measured every 2 min to assess changes in end-expiratory lung volume. RESULTS: After training, the increase in peak oxygen uptake was not statistically significant; however, the peak work rate increased by 12.9 +/- 10.3 W (p < 0.01). For the CWR test performed at the same work rate both before and after training, ventilation and breathing frequency (f) were lower after training (average, 1.97 L/min and 3.2 breaths/min, respectively; p < 0.01) and IC was greater (by an average of 133 mL, p < 0.05), signifying decreased hyperinflation. The increase in IC at the point of termination in the shortest CWR test for each individual (defined as isotime) correlated well with both the decreased f (r = 0.63, p = 0.001) and with the increase in CWR exercise endurance (average, 13.1 min, r = 0.46, p = 0.023). CONCLUSIONS: Exercise training in patients with severe COPD dramatically improves submaximal exercise endurance. Decreased dynamic hyperinflation may, in part, mediate the improvement in exercise endurance by delaying the attainment of a critically high inspiratory lung volume.

Aged↗

PubMed2004

Effects of testosterone and resistance training in men with chronic obstructive pulmonary disease.

Dysfunction of the muscles of ambulation contributes to exercise intolerance in chronic obstructive pulmonary disease (COPD). Men with COPD have high prevalence of low testosterone levels, which may contribute to muscle weakness. We determined effects of testosterone supplementation (100 mg of testosterone enanthate injected weekly) with or without resistance training (45 minutes three times weekly) on body composition and muscle function in 47 men with COPD (mean FEV(1) = 40% predicted) and low testosterone levels (mean = 320 ng/dl). Subjects were randomized to 10 weeks of placebo injections + no training, testosterone injections + no training, placebo injections + resistance training, or testosterone injections + resistance training. Testosterone injections yielded a mean increase of 271 ng/dl in the nadir serum testosterone concentration (to the middle of the normal range for young men). The lean body mass (by dual-energy X-ray absorptiometry) increase averaged 2.3 kg with testosterone alone and 3.3 kg with combined testosterone and resistance training (p < 0.001). Increase in one-repetition maximum leg press strength averaged 17.2% with testosterone alone, 17.4% with resistance training alone, and 26.8% with testosterone + resistance training (p < 0.001). Interventions were well tolerated with no abnormalities in safety measures. Further studies are required to determine long-term benefits of adding testosterone supplementation and resistance training to rehabilitative programs for carefully screened men with COPD and low testosterone levels.

Aged↗

PubMed2003

Benefits of supplemental oxygen in exercise training in nonhypoxemic chronic obstructive pulmonary disease patients.

Supplemental oxygen improves exercise tolerance of normoxemic and hypoxemic chronic obstructive pulmonary disease (COPD) patients. We determined whether nonhypoxemic COPD patients undergoing exercise training while breathing supplemental oxygen achieve higher intensity and therefore improve exercise capacity more than patients breathing air. A double-blinded trial was performed involving 29 nonhypoxemic patients (67 years, exercise SaO2 > 88%) with COPD (FEV1 = 36% predicted). All exercised on cycle ergometers for 45 minutes, 3 times per week for 7 weeks at high-intensity targets. During exercise, they received oxygen (3 L/minute) (n = 14) or compressed air (3 L/minute) (n = 15). Both groups had a higher exercise tolerance after training and when breathing oxygen. However, the oxygen-trained group increased the training work rate more rapidly than the air-trained group. The mean +/- SD work rate during the last week was 62 +/- 19 W (oxygen-trained group) and 52 +/- 22 W (air-trained group) (p < 0.01). After training, endurance in constant work rate tests increased more in the oxygen-trained group (14.5 minutes) than in the air-trained group (10.5 minutes) (p < 0.05). At isotime, the breathing rate decreased four breaths per minute in the oxygen-trained group and one breath per minute in the air-trained group (p = 0.001). We conclude that supplemental oxygen provided during high-intensity training yields higher training intensity and evidence of gains in exercise tolerance in laboratory testing.

Aged↗

PubMed2003

A treadmill ramp protocol using simultaneous changes in speed and grade.

INTRODUCTION: A treadmill exercise test requiring a low initial metabolic rate that then increments the work rate linearly to reach the subject's limit of tolerance in approximately 10 min would have significant advantages for exercise testing and rehabilitation of subjects with impaired exercise tolerance. METHODS: We developed such a treadmill protocol that uses a linear increase in walking speed coupled with a curvilinear increase in treadmill grade to yield a linear increase in work rate. RESULTS: Twenty-two healthy, sedentary subjects performed both this new treadmill protocol and a standard cycle ergometry ramp protocol eliciting similar work rate profiles. The low initial treadmill speed and grade resulted in a low initial metabolic rate, commensurate with unloaded pedaling on a cycle ergometer (average [OV0312]O2 = 0.54 +/- 0.16 vs 46 +/- 0.12 l x min(-1)). This combination of simultaneous increase in speed and grade yielded a linear work rate and its oxygen uptake response (R2 = 0.96 +/- 0.03) with a slope of 11.4 +/- 2.4 ml x min(-1) x W(-1)-slightly, but significantly, higher than on the cycle (9.6 +/- 2.0 ml x min(-1) x W(-1)). This difference was attributed to unmeasured work associated, for example, with additional limb movements and frictional losses. As previously demonstrated, both the peak oxygen uptake and the estimated lactate threshold were higher on the treadmill than for cycle ergometry (averaging 23% and 27%, respectively, in these subjects). CONCLUSION: This treadmill protocol provides a linear profile of work rate as is currently standard for cycle ergometry and is appropriate for testing of subjects with low exercise tolerance.

Adolescent↗

PubMed2002

Effect of hyperoxia on gas exchange and lactate kinetics following exercise onset in nonhypoxemic COPD patients.

STUDY OBJECTIVES: The slow oxygen uptake (VO(2)) kinetics observed in COPD patients is a manifestation of skeletal muscle dysfunction of multifactorial origin. We determined whether oxygen supplementation during exercise makes the dynamic VO(2) response faster and reduces transient lactate increase. DESIGN: Ten patients with severe COPD (ie, mean [+/- SD] FEV(1), 31 +/- 10% predicted) and 7 healthy subjects of similar age performed four repetitions of the transition between rest and 10 min of moderate-intensity, constant-work rate exercise while breathing air or 40% oxygen in random order. Minute ventilation (VE), gas exchange, and heart rate (HR) were recorded breath-by-breath, and arterialized venous pH, PCO(2), and lactate levels were measured serially. RESULTS: Compared to healthy subjects, the time constants (tau) for VO(2), HR, carbon dioxide output (VCO(2)), and VE kinetic responses were significantly slower in COPD patients than in healthy subjects (70 +/- 8 vs 44 +/- 3 s, 98 +/- 14 vs 44 +/- 8 s, 86 +/- 8 vs 61 +/- 4 s, and 81 +/- 7 vs 62 +/- 4 s, respectively; p < 0.05). Hyperoxia decreased end-exercise E in the COPD group but not the healthy group. Hyperoxia did not increase the speed of VO(2) kinetics but significantly slowed VCO(2) and E response dynamics in both groups. Only small increases in lactate occurred with exercise, and this increase did not correlate with the tau for VO(2). CONCLUSION: In nonhypoxemic COPD patients performing moderate exercise, the lower ventilatory requirement induced by oxygen supplementation is not related to improved muscle function but likely stems from direct chemoreceptor inhibition.

Aged↗