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Exercise-induced Bronchodilation Equalizes Exercise Ventilatory Mechanics despite Variable Baseline Airway Function in Asthma.
Rossman, MJ, Petrics, G, Klansky, A, Craig, K, Irvin, CG, Haverkamp, HC
Medicine and science in sports and exercise. 2022;(2):258-266
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Abstract
PURPOSE We quantified the magnitude of exercise-induced bronchodilation in adult asthmatics under conditions of narrowed and dilated airways. We then assessed the effect of the bronchodilation on ventilatory capacity and the extent of ventilatory limitation during exercise. METHODS Eleven asthmatics completed three exercise bouts on a cycle ergometer. Exercise was preceded by no treatment (trialCON), inhaled β2 agonist (trialBD), or a eucapnic voluntary hyperpnea challenge (trialBC). Maximal expiratory flow-volume maneuvers (MEFV) were performed before and within 40 s of exercise cessation. Exercise tidal flow-volume loops were placed within the preexercise and postexercise MEFV curve and used to determine expiratory flow limitation and maximum ventilatory capacity (V˙ECap). RESULTS Preexercise airway function was different among the trials (forced expiratory volume 1 s during trialCON, trialBD, and trialBC = 3.3 ± 0.8 L, 3.8 ± 0.8 L, and 2.9 ± 0.8 L, respectively; P < 0.05). Maximal expired airflow increased with exercise during all three trials, but the increase was greatest during trialBC (delta forced expiratory volume 1 s during trialCON, trialBD, and trialBC = +12.2% ± 13.1%, +5.2% ± 5.7%, +28.1% ± 15.7%). Thus, the extent of expiratory flow limitation decreased, and V˙ECap increased, when the postexercise MEFV curve was used. During trialCON and trialBC, actual exercise ventilation exceeded V˙ECap calculated with the preexercise MEFV curve in seven and nine subjects, respectively. CONCLUSIONS These findings demonstrate the critical importance of exercise bronchodilation in the asthmatic with narrowed airways. Of clinical relevance, the results also highlight the importance of assessing airway function during or immediately after exercise in asthmatic persons; otherwise, mechanical limitations to exercise ventilation will be overestimated.
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VESTPD as a measure of ventilatory acclimatization to hypobaric hypoxia.
Loeppky, JA, Sheard, AC, Salgado, RM, Mermier, CM
Physiology international. 2016;(3):377-391
Abstract
This study compared the ventilation response to an incremental ergometer exercise at two altitudes: 633 mmHg (resident altitude = 1,600 m) and following acute decompression to 455 mmHg (≈4,350 m altitude) in eight male cyclists and runners. At 455 mmHg, the VESTPD at RER <1.0 was significantly lower and the VEBTPS was higher because of higher breathing frequency; at VO2max, both VESTPD and VEBTPS were not significantly different. As percent of VO2max, the VEBTPS was nearly identical and VESTPD was 30% lower throughout the exercise at 455 mmHg. The lower VESTPD at lower pressure differs from two classical studies of acclimatized subjects (Silver Hut and OEII), where VESTPD at submaximal workloads was maintained or increased above that at sea level. The lower VESTPD at 455 mmHg in unacclimatized subjects at submaximal workloads results from acute respiratory alkalosis due to the initial fall in HbO2 (≈0.17 pHa units), reduction in PACO2 (≈5 mmHg) and higher PAO2 throughout the exercise, which are partially pre-established during acclimatization. Regression equations from these studies predict VESTPD from VO2 and PB in unacclimatized and acclimatized subjects. The attainment of ventilatory acclimatization to altitude can be estimated from the measured vs. predicted difference in VESTPD at low workloads after arrival at altitude.
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3.
High-flux dialysis improves pulmonary ventilation function in uremic patients.
Lin, H, Wu, YG, Zhang, JH, Kan, M
Molecular medicine reports. 2013;(5):1603-6
Abstract
Lung injury commonly accompanies uremia caused by renal failure. Uremia is typically treated using hemodialysis (dialysis) to restore electrolyte and fluid balance. A more recent, less commonly used method, high-flux dialysis, has not yet been investigated for its potential benefit to lung function. The aim of the present study was to determine whether high‑flux dialysis affects pulmonary function. We assessed various pulmonary function parameters in patients with uremia before and after routine or high‑flux dialysis. Pulmonary function was assessed via determination of the forced vital capacity (FVC), maximum breathing capacity (MBC), forced expiratory volume in 1 sec (FEV1), peak expiratory flow (PEF), maximal midexpiratory flow (MMEF) curve, maximal expiratory flow in 25% vital capacity (V25) and diffusion capacity of the lungs for carbon monoxide (DLco) in 42 patients with uremia and 24 healthy individuals. Patients with uremia were divided into two groups; the high‑flux group (treated with high-flux dialysis; n=21) and the routine group (treated with conventional dialysis; n=21). Lung function was reassessed in the two groups after 3 months of dialysis. The two groups of patients with uremia exhibited reduced lung function parameters compared with healthy individuals (all P<0.05), indicating the presence of impaired lung function secondary to uremia. Following dialysis, the FEV1, PEF, MMEF and V25 values increased significantly compared with their respective baseline values prior to treatment for each group (ANOVA, P<0.05). Furthermore, increases were more marked in patients treated with high-flux dialysis compared with those treated using routine dialysis (P<0.05). Thus, lung injury caused by uremia was shown to be improved following dialysis, with high-flux dialysis offering a greater benefit than routine dialysis.
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Influence of dichloroacetate on pulmonary gas exchange and ventilation during incremental exercise in healthy humans.
Wilkerson, DP, Campbell, IT, Blackwell, JR, Berger, NJ, Jones, AM
Respiratory physiology & neurobiology. 2009;(3):224-9
Abstract
We hypothesised that dichloroacetate (DCA) would reduce blood lactate accumulation, pulmonary carbon dioxide output (.V(CO2)) and ventilation (.V(E)) at sub-maximal work rates, and improve exercise tolerance during incremental exercise in healthy humans. Nine males (mean+/-SD, age 27+/-4 years) completed, in random order, two ramp incremental cycle ergometer tests to the limit of tolerance following the intravenous infusion of DCA (75 mg/kg body mass in 80 ml saline) or an equivalent volume of saline (as placebo). Relative to control, blood [lactate] was significantly reduced by DCA immediately before exercise (CON: 0.7+/-0.2 vs. DCA: 0.5+/-0.2mM; P<0.05) and throughout exercise until 630s (P<0.05). Blood [HCO(3)(-)] was significantly higher in the DCA condition from 360s until 720s of exercise (P<0.05). .V(CO2) and .V(E) were both lower throughout exercise in the DCA condition, with the differences reaching significance at 90 and 180s for .V(CO2) (P<0.05) and at 90, 180, 450, 540, 630, and 810s for .V(E) (P<0.05). Exercise tolerance was not significantly altered (CON: 1029+/-109 vs. DCA: 1045+/-101s). Infusion of DCA resulted in reductions in blood [lactate], .V(CO2) and .V(E) during sub-maximal incremental exercise, consistent with the existence of a link between the bicarbonate buffering of metabolic acidosis and increased CO(2) output. However, the reduced blood lactate accumulation during sub-maximal exercise with DCA did not enhance exercise tolerance.
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5.
Effects of a 4-week training with voluntary hypoventilation carried out at low pulmonary volumes.
Woorons, X, Mollard, P, Pichon, A, Duvallet, A, Richalet, JP, Lamberto, C
Respiratory physiology & neurobiology. 2008;(2):123-30
Abstract
This study investigated the effects of training with voluntary hypoventilation (VH) at low pulmonary volumes. Two groups of moderately trained runners, one using hypoventilation (HYPO, n=7) and one control group (CONT, n=8), were constituted. The training consisted in performing 12 sessions of 55 min within 4 weeks. In each session, HYPO ran 24 min at 70% of maximal O(2) consumption ( [V(02max)) with a breath holding at functional residual capacity whereas CONT breathed normally. A V(02max) and a time to exhaustion test (TE) were performed before (PRE) and after (POST) the training period. There was no change in V(O2max), lactate threshold or TE in both groups at POST vs. PRE. At maximal exercise, blood lactate concentration was lower in CONT after the training period and remained unchanged in HYPO. At 90% of maximal heart rate, in HYPO only, both pH (7.36+/-0.04 vs. 7.33+/-0.06; p<0.05) and bicarbonate concentration (20.4+/-2.9 mmolL(-1) vs. 19.4+/-3.5; p<0.05) were higher at POST vs. PRE. The results of this study demonstrate that VH training did not improve endurance performance but could modify the glycolytic metabolism. The reduced exercise-induced blood acidosis in HYPO could be due to an improvement in muscle buffer capacity. This phenomenon may have a significant positive impact on anaerobic performance.
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Impact of a correct breathing stereotype on pulmonary minute ventilation, blood gases and acid-base balance in post-myocardial infarction patients.
Vasiliauskas, D, Jasiukeviciene, L
European journal of cardiovascular prevention and rehabilitation : official journal of the European Society of Cardiology, Working Groups on Epidemiology & Prevention and Cardiac Rehabilitation and Exercise Physiology. 2004;(3):223-7
Abstract
STUDY OBJECTIVE The aim of the study was to evaluate the impact of a long-term (6-month) correct breathing stereotype on minute ventilation, capillary blood gases and acid-base balance in post-myocardial infarction patients. METHODS Fifty-five men (age 57.2 +/- 12.5) were examined 2 months later after myocardial infarction. Spirometry and assessment of acid-base balance and capillary blood gases were performed at rest and repeated after 10 days and 6 months. Breathing correction was taught over 5 days. A session for the control and maintenance of the correct breathing skills was hosted once a month (during the 6-month period). RESULTS Changes of minute ventilation, capillary blood gases and acid-base balance were revealed in 55% of patients 2 months later after myocardial infarction. Twenty patients (group I) were randomly selected for breathing correction while 10 patients made up the control group (group II). After breathing correction minute ventilation significantly decreased (18.5 +/- 5.5 versus 9.8 +/- 2.5 l/min), oxygen ventilatory equivalent decreased (39.8 +/- 5.2 versus 22.5 +/- 3.8), partial pressure of blood carbon dioxide increased (33.2 +/- 1.7 versus 44.2 +/- 2.5 mmHg), plasma bicarbonate concentration augmented (19.1 +/- 2.2 versus 24.5 +/- 1.8 mmol/l), base excess normalized (-2.90 +/- 2.5 versus +1.3 +/- 2.1 mmol/l), and pH shifted to more alkaline value (7.36 +/- 0.01 versus 7.43 +/- 0.02). CONCLUSIONS A long-term correct breathing stereotype improved respiratory function and could be an additional measure in rehabilitation programmes for post-myocardial infarction patients.
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7.
Serum lipoprotein cholesterols in older oarsmen.
Yoshiga, CC, Higuchi, M, Oka, J
European journal of applied physiology. 2002;(3):228-32
Abstract
We evaluated effects of age and rowing on concentrations of lipids and lipoprotein cholesterols in the blood. Maximal oxygen uptake (VO(2max)), and concentrations of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were measured in 17 oarsmen [mean (SD)] [age 64 (4) years, body mass 69 (6) kg] and in sedentary men [age 65 (3) years, body mass 70 (7) kg] who were matched on the basis of body size. Also the variables were obtained from young oarsmen [age 22 (2) years, body mass 70 (4) kg] and young sedentary men [age 22 (3) years, body mass 69 (7) kg]. The percentage body fat of the older oarsmen was lower than that of the older sedentary men [18 (4)% compared to 23 (4)%, P<0.05], but it was similar to that of the young sedentary men [17 (4)%]. Although older oarsmen possessed a lower VO(2max) than the young oarsmen [3.0 (0.4) l.min(-1) compared to 4.1 (0.3) l.min(-1), P<0.01], they showed a VO(2max) similar to that of the young sedentary men [3.1 (0.5) l.min(-1)] but a higher value than obtained from the older sedentary men [2.2 (0.3) l.min(-1), P<0.05]. Although the indices of risk factors for coronary artery disease in the older oarsmen were higher than those in the young oarsmen [LDL-C/HDL-C 1.7 (0.2) compared to 1.3 (0.4), TC/HDL-C 3.1 (0.2) compared to 2.6(0.4), P<0.05], they were lower than those in both the older [2.1 (0.3), 3.6 (0.3), P<0.05] and the young sedentary men [2.1 (0.4), 3.5 (0.4), P<0.05]. The results suggest that rowing is an appropriate type of exercise for the promotion of health.
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A comparison of once daily fexofenadine versus the combination of montelukast plus loratadine on domiciliary nasal peak flow and symptoms in seasonal allergic rhinitis.
Wilson, AM, Orr, LC, Coutie, WJ, Sims, EJ, Lipworth, BJ
Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology. 2002;(1):126-32
Abstract
BACKGROUND The combination of montelukast (ML) and loratadine (LT) has previously been shown to be superior to either drug alone in managing seasonal allergic rhinitis (SAR), whilst fexofenadine (FEX) has been shown to be better than LT as monotherapy. OBJECTIVES We wished to compare ML + LT vs. FEX alone for effects on daily measurements (am/pm) of peak inspiratory flow (PIF) and symptoms. METHODS Thirty-seven patients with SAR (skin prick positive to grass pollen) were randomised into a single-blind, double-dummy placebo (PL)-controlled cross-over study during the grass pollen season, comparing 2 weeks of once daily treatment with (a) 120mg FEX or (b) 10mg ML + 10mg LT. There was a 7-10 day placebo run-in and washout prior to each randomised treatment. The average of am/pm PIF (the primary outcome variable) was analysed. Patients recorded their symptom scores (from 0 to 3) twice daily, for nasal blockage, discharge, itching and sneezing with; total eye symptoms, ocular cromoglycate use, and daily activity. The total nasal symptom score was calculated as a composite (out of 24). RESULTS There were no significant differences between baselines after the run-in and washout placebos for any variables. There were significant (P < 0.05, Bonferroni) improvements in all symptoms and PIF compared to pooled placebo with both treatments for all end-points, but no differences between the two treatment regimes (as means and within-treatment 95% confidence intervals): PIF: PL 102 (98-107), FEX 111 (107-116), ML+LT 113 (109-118); total nasal symptoms: PL 7.4 (6.7-2.0), FEX 5.0 (4.3-5.7), ML + LT 4.0 (3.3-4.7). CONCLUSIONS Once daily FEX as monotherapy was equally effective as the combination of once daily ML + LT in improving nasal peak flow and controlling symptoms in SAR. Further studies are indicated to assess whether ML confers additional benefits to FEX in SAR.