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Hossri C, Araujo F, Baldi B, Otterstetter R, Uemoto V, Carvalho C, Mastrocola L, Albuquerque A. Association among cardiopulmonary and metabolic rehabilitation, arrhythmias, and myocardial ischemia responses of patients with HFpEF or HFmrEF. Braz J Med Biol Res 2024; 57:e13174. [PMID: 38451608 PMCID: PMC10913385 DOI: 10.1590/1414-431x2024e13174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 02/01/2024] [Indexed: 03/08/2024] Open
Abstract
There's limited evidence of the potential benefits of cardiopulmonary and metabolic rehabilitation (CPMR) in patients with heart failure with preserved ejection fraction (HFpEF) or mildly reduced ejection fraction (HFmrEF) and coronary artery disease (CAD). The aim of this study was to investigate the impact of CPMR on the myocardial ischemia response (MIR), exercise-induced arrhythmias (EIA), New York Heart Association (NYHA) functional class, heart rate recovery (HRR), Borg CR10 perceived symptoms, and the SF-36 physical and mental health summary scores. A prospective cohort study was conducted with 106 patients undergoing 12 weeks of CPMR who completed two exercise tests pre- and post-CPMR: 1) maximum incremental test (CPX) and 2) submaximal constant load test (SUB). After CPMR, the effects on MIR, EIA, NYHA functional class, and HRR during both tests were analyzed. There was a significant change in NYHA functional classes after CPMR, with 96% of the patients in class I (vs 62% pre-CPMR, P<0.0001), 4% in class II (vs 32%), and none in class III (vs 6%). There was a significant reduction in the frequency of EIA (P<0.05) and MIR (P<0.001) and a significantly improved performance on both CPX and SUB tests (P<0.0001). Lastly, there was significant progress in the recovery metrics like HRR (P<0.0001), the Borg CR10 (P<0.0001), and the SF-36 summary scores (P<0.0001). The CPMR resulted in a significant decrease in EIA, delayed ischemia threshold in CPX and SUB tests, increased functional capacity, and improved quality of life.
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Affiliation(s)
- C.A.C. Hossri
- Hospital do Coração, Associação Beneficente Síria, São Paulo, SP, Brasil
- Pneumologia-Incor, Instituto do Coração, Hospital das Clínicas (HCFMUSP), Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
| | | | - B.G. Baldi
- Hospital do Coração, Associação Beneficente Síria, São Paulo, SP, Brasil
- Pneumologia-Incor, Instituto do Coração, Hospital das Clínicas (HCFMUSP), Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
| | - R. Otterstetter
- School of Exercise and Nutrition Sciences, University of Akron, Akron, OH, USA
| | - V.R. Uemoto
- Setor da Bioengenharia, Instituto Dante Pazzanese, São Paulo, SP, Brasil
| | - C.R.R. Carvalho
- Hospital do Coração, Associação Beneficente Síria, São Paulo, SP, Brasil
- Pneumologia-Incor, Instituto do Coração, Hospital das Clínicas (HCFMUSP), Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
| | - L.E. Mastrocola
- Hospital do Coração, Associação Beneficente Síria, São Paulo, SP, Brasil
| | - A.L.P. Albuquerque
- Hospital do Coração, Associação Beneficente Síria, São Paulo, SP, Brasil
- Pneumologia-Incor, Instituto do Coração, Hospital das Clínicas (HCFMUSP), Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
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Wiecha S, Kasiak PS, Cieśliński I, Maciejczyk M, Mamcarz A, Śliż D. Modeling Physiological Predictors of Running Velocity for Endurance Athletes. J Clin Med 2022; 11:jcm11226688. [PMID: 36431165 PMCID: PMC9696488 DOI: 10.3390/jcm11226688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/26/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Properly performed training is a matter of importance for endurance athletes (EA). It allows for achieving better results and safer participation. Recently, the development of machine learning methods has been observed in sports diagnostics. Velocity at anaerobic threshold (VAT), respiratory compensation point (VRCP), and maximal velocity (Vmax) are the variables closely corresponding to endurance performance. The primary aims of this study were to find the strongest predictors of VAT, VRCP, Vmax, to derive and internally validate prediction models for males (1) and females (2) under TRIPOD guidelines, and to assess their machine learning accuracy. Materials and Methods: A total of 4001 EA (nmales = 3300, nfemales = 671; age = 35.56 ± 8.12 years; BMI = 23.66 ± 2.58 kg·m-2; VO2max = 53.20 ± 7.17 mL·min-1·kg-1) underwent treadmill cardiopulmonary exercise testing (CPET) and bioimpedance body composition analysis. XGBoost was used to select running performance predictors. Multivariable linear regression was applied to build prediction models. Ten-fold cross-validation was incorporated for accuracy evaluation during internal validation. Results: Oxygen uptake, blood lactate, pulmonary ventilation, and somatic parameters (BMI, age, and body fat percentage) showed the highest impact on velocity. For VAT R2 = 0.57 (1) and 0.62 (2), derivation RMSE = 0.909 (1); 0.828 (2), validation RMSE = 0.913 (1); 0.838 (2), derivation MAE = 0.708 (1); 0.657 (2), and validation MAE = 0.710 (1); 0.665 (2). For VRCP R2 = 0.62 (1) and 0.67 (2), derivation RMSE = 1.066 (1) and 0.964 (2), validation RMSE = 1.070 (1) and 0.978 (2), derivation MAE = 0.832 (1) and 0.752 (2), validation MAE = 0.060 (1) and 0.763 (2). For Vmax R2 = 0.57 (1) and 0.65 (2), derivation RMSE = 1.202 (1) and 1.095 (2), validation RMSE = 1.205 (1) and 1.111 (2), derivation MAE = 0.943 (1) and 0.861 (2), and validation MAE = 0.944 (1) and 0.881 (2). Conclusions: The use of machine-learning methods allows for the precise determination of predictors of both submaximal and maximal running performance. Prediction models based on selected variables are characterized by high precision and high repeatability. The results can be used to personalize training and adjust the optimal therapeutic protocol in clinical settings, with a target population of EA.
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Affiliation(s)
- Szczepan Wiecha
- Department of Physical Education and Health in Biala Podlaska, Faculty in Biala Podlaska, Józef Piłsudski University of Physical Education in Warsaw, 21-500 Biala Podlaska, Poland
- Correspondence: (S.W.); (D.Ś.)
| | - Przemysław Seweryn Kasiak
- Student’s Scientific Circle of Lifestyle Medicine, 3rd Department of Internal Medicine and Cardiology, Medical University of Warsaw, 04-749 Warsaw, Poland
| | - Igor Cieśliński
- Department of Physical Education and Health in Biala Podlaska, Faculty in Biala Podlaska, Józef Piłsudski University of Physical Education in Warsaw, 21-500 Biala Podlaska, Poland
| | - Marcin Maciejczyk
- Department of Physiology and Biochemistry, Faculty of Physical Education and Sport, University of Physical Education in Krakow, 31-571 Kraków, Poland
| | - Artur Mamcarz
- 3rd Department of Internal Medicine and Cardiology, Medical University of Warsaw, 04-749 Warsaw, Poland
| | - Daniel Śliż
- 3rd Department of Internal Medicine and Cardiology, Medical University of Warsaw, 04-749 Warsaw, Poland
- Correspondence: (S.W.); (D.Ś.)
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Parpa K, Michaelides M. Aerobic capacity of professional soccer players before and after COVID-19 infection. Sci Rep 2022; 12:11850. [PMID: 35831351 PMCID: PMC9279307 DOI: 10.1038/s41598-022-16031-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 07/04/2022] [Indexed: 01/31/2023] Open
Abstract
This investigation aimed to assess the aerobic capacity of professional soccer players pre-and post-COVID-19 infection. Twenty-one division-1 elite soccer players (age 24.24 ± 5.75 years, height 178.21 ± 5.44 cm, weight 74.12 ± 5.21 kg) participated in this study. This observational study compared the same players' aerobic capacity pre-, and 60-days post COVID-19 recovery. The statistical analysis demonstrated that the infected players had significantly lower VO2max values [t(20) = 5.17, p < 0.01, d = 0.613 (medium effect)], and significantly lower VO2 values at respiratory compensation point (RC) [t(20) = 2.97, p < 0.05, d = 0.39 (small effect)] after recovery. Furthermore, results indicated a significantly lower running time (RT) on the treadmill [t(20) = 4.84, p < 0.01, d = 0.46 (small effect)] when compared to the results that were obtained before they got infected. In addition, velocity at VO2max (VVO2max) was significantly lower [t(20) = 2.34, p < 0.05, d = 0.41 (small effect)] and the heart rate values at ventilatory threshold (VT) [t(20) = −2.79, p < 0.01, d = 0.55 (medium effect)] and RC [t(20) = −3.72, p < 0.01, d = 0.52 (medium effect)] were significantly higher post-recovery. The aforementioned findings indicate that post COVID-19 soccer players may not reach full recovery at two months. Therefore, our results highlight that further adaptations and improvements are needed with regard to aerobic capacity before soccer players return to professional games.
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Affiliation(s)
- Koulla Parpa
- University of Central Lancashire, Cyprus Campus, University Avenue 12-14, 7080, Pyla, Cyprus.
| | - Marcos Michaelides
- University of Central Lancashire, Cyprus Campus, University Avenue 12-14, 7080, Pyla, Cyprus
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Kominami K, Imahashi K, Katsuragawa T, Murakami M, Akino M. The Ratio of Oxygen Uptake From Ventilatory Anaerobic Threshold to Respiratory Compensation Point Is Maintained During Incremental Exercise in Older Adults. Front Physiol 2022; 13:769387. [PMID: 35309068 PMCID: PMC8927902 DOI: 10.3389/fphys.2022.769387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 02/07/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction The period from ventilatory anaerobic threshold (VAT) to respiratory compensation point (RCP) during incremental exercise (isocapnic buffering phase) has been associated with exercise tolerance and skeletal muscle composition. However, several reports compare younger and older healthy adults, and specific age-related changes are unclear. This study aimed to examine the oxygen uptake (VO2) from VAT to RCP and its change over time in younger and older healthy adults. Methods A total of 126 consecutive participants were divided into two groups (95 younger and 31 older than 50 years of age) who underwent cardiopulmonary exercise testing, and VAT and RCP were determined. The ratio (RCP/VAT) and difference (ΔVO2 RCP-VAT) were calculated from the VO2 of VAT and RCP and compared between groups and ages. Statistical analyses included t-tests and Spearman’s correlation tests, and the significance level was set at <5%. Results RCP/VAT was not significantly different (1.40 ± 0.19 vs. 1.59 ± 0.24, p = 0.057) but weakly correlated with age (r = −0.229, p = 0.013, y = −0.0031x + 1.7588, lowering rate: 0.185%/year). Conversely, ΔVO2 RCP-VAT was significantly lower in the older group (7.7 ± 3.1 vs. 13.8 ± 4.9 ml/kg/min, p < 0.001) and correlated significantly with age (r = −0.499; p < 0.001; y = −0.1303x + 16.855; lowering rate, 0.914%/year). Conclusion ΔVO2 RCP-VAT was considered to be a poor indicator of lactate buffering capacity in the IB phase because both VAT and RCP were greatly affected by age-related decline. Conversely, RCP/VAT was suggested to be an index not easily affected by aging.
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Affiliation(s)
- Kazuyuki Kominami
- Cardiac Rehabilitation Center, Sapporo Ryokuai Hospital, Sapporo, Japan
- *Correspondence: Kazuyuki Kominami,
| | - Keiko Imahashi
- Cardiac Rehabilitation Center, Sapporo Ryokuai Hospital, Sapporo, Japan
| | - Toko Katsuragawa
- Cardiac Rehabilitation Center, Sapporo Ryokuai Hospital, Sapporo, Japan
| | - Mitsuyo Murakami
- Cardiac Rehabilitation Center, Sapporo Ryokuai Hospital, Sapporo, Japan
| | - Masatoshi Akino
- Department of Cardiovascular Medicine, Sapporo Ryokuai Hospital, Sapporo, Japan
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Ozkaya O, Balci GA, As H, Yildiztepe E. A new technique to analyse threshold-intensities based on time dependent change-points in the ratio of minute ventilation and end-tidal partial pressure of carbon-dioxide production. Respir Physiol Neurobiol 2021; 294:103735. [PMID: 34229064 DOI: 10.1016/j.resp.2021.103735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 06/18/2021] [Accepted: 07/01/2021] [Indexed: 11/19/2022]
Abstract
The aim of this study was to test the utility and effectiveness of an alternative computational approach to threshold-intensities based on time dependent change-points in minute ventilation divided by end-tidal partial pressure of CO2 (VE/PETCO2) to reveal whether respiratory compensation point (RCP) is a third ventilatory threshold, or not. Ten recreationally active young adults and ten well-trained athletes volunteered to take part in this study. Following incremental ramp tests, gas exchange threshold (GET) and respiratory compensation point (RCP) were respectively evaluated by the slopes of VCO2-VO2 and VE-VCO2 using the Innocor system automatically. Respiratory threshold (RT) was analysed based on time dependent change-points in the VE/PETCO2 using binary segmentation algorithm. Additionally, those intersections were analysed independently by two experienced investigators using a visual identification technique in a double-blind design. According to the results, in the recreationally active group, there were the first (GET1) and the second (GET2) gas exchange thresholds which were identical with the RT1 (139 W; 1.9 L⋅min-1 of VO2; 1.73 L⋅min-1 of VCO2; 49.9 L⋅min-1 of VE versus 139 W; 1.88 L⋅min-1; 1.7 L⋅min-1; 49 L⋅min-1, respectively) and RT2 (186 W; 2.39 L⋅min-1 of VO2; 2.44 L⋅min-1 of VCO2; 66 L⋅min-1 of VE versus 187 W; 2.41 L⋅min-1; 2.49 L⋅min-1; 65.7 L⋅min-1, respectively). However, there were three threshold intensities which were determined by GET1, GET2, and RCP in well-trained athletes. Additionally, RT1, RT2, and RT3 were determined as valid surrogates of the GET1 (194 W; 2.56 L⋅min-1 of VO2; 1.99 L⋅min-1 of VCO2; 57.5 L⋅min-1 of VE versus 192 W; 2.61 L⋅min-1; 1.99 Lmin-1; 57.7 L⋅min-1, respectively), GET2 (267 W; 3.6 L⋅min-1 of VO2; 3.29 L⋅min-1 of VCO2; 94.5 L⋅min-1 of VE versus 266 W; 3.58 L⋅min-1; 3.26 L⋅min-1; 93.4 L⋅min-1, respectively), and RCP (324 W; 4.05 L⋅min-1 of VO2; 4.13 L⋅min-1 of VCO2; 124 L⋅min-1 of VE versus 322 W; 4.02 L⋅min-1; 4.07 L⋅min-1; 122 L⋅min-1, respectively) in well-trained athletes. There were high levels of agreements between the power outputs determined by traditional techniques and newly proposed change-points in RT. All markers were strongly correlated (p < 0.001). It was shown that RT technique can provide an accurate threshold determination. Furthermore, the RCP was observed as a third threshold-intensity for well-trained athletes but not for recreationally active young adults.
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Affiliation(s)
- Ozgur Ozkaya
- Department of Coaching Education, Faculty of Sport Sciences, Ege University, 35050, Bornova, Izmir, Turkey.
| | - Gorkem A Balci
- Department of Coaching Education, Faculty of Sport Sciences, Ege University, 35050, Bornova, Izmir, Turkey
| | - Hakan As
- Department of Sports and Health Sciences, Institution of Health Sciences, Ege University, 35050, Bornova, Izmir, Turkey
| | - Engin Yildiztepe
- Department of Statistics, Faculty of Science, Dokuz Eylul University, 35390, Buca, Izmir, Turkey
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Ward SA. Ventilation/carbon dioxide output relationships during exercise in health. Eur Respir Rev 2021; 30:30/160/200160. [PMID: 33853883 PMCID: PMC9488729 DOI: 10.1183/16000617.0160-2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/22/2020] [Indexed: 11/27/2022] Open
Abstract
“Ventilatory efficiency” is widely used in cardiopulmonary exercise testing to make inferences regarding the normality (or otherwise) of the arterial CO2 tension (PaCO2) and physiological dead-space fraction of the breath (VD/VT) responses to rapid-incremental (or ramp) exercise. It is quantified as: 1) the slope of the linear region of the relationship between ventilation (V′E) and pulmonary CO2 output (V′CO2); and/or 2) the ventilatory equivalent for CO2 at the lactate threshold (V′E/V′CO2) or its minimum value (V′E/V′CO2min), which occurs soon after but before respiratory compensation. Although these indices are normally numerically similar, they are not equally robust. That is, high values for V′E/V′CO2 and V′E/V′CO2min provide a rigorous index of an elevated VD/VT when PaCO2 is known (or can be assumed) to be regulated. In contrast, a high V′E–V′CO2 slope on its own does not, as account has also to be taken of the associated normally positive and small V′E intercept. Interpretation is complicated by factors such as: the extent to which PaCO2 is actually regulated during rapid-incremental exercise (as is the case for steady-state moderate exercise); and whether V′E/V′CO2 or V′E/V′CO2min provide accurate reflections of the true asymptotic value of V′E/V′CO2, to which the V′E–V′CO2 slope approximates at very high work rates. The efficiency of CO2 clearance at the lungs in exercise is estimated from the relationship between ventilation and CO2 elimination rate. It is compromised in lung and cardiovascular disease, stressing breathing and shortness of breath, and therefore impairing exercise capacity.https://bit.ly/3gYY866
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Affiliation(s)
- Susan A Ward
- Human Bio-Energetics Research Centre, Crickhowell, Powys, UK
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Nakahara H, Ueda SY, Miyamoto T. Low Frequency Severe-Intensity Interval Training Markedly Alters Respiratory Compensation Point During Incremental Exercise in Untrained Male. Front Physiol 2020; 11:1100. [PMID: 33013469 PMCID: PMC7498695 DOI: 10.3389/fphys.2020.01100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 08/10/2020] [Indexed: 11/13/2022] Open
Abstract
This study investigated the effect of low-frequency severe-intensity interval training on the respiratory compensation point (RCP) during incremental exercise test. Eighteen healthy males (age; 20.7 ± 2.2 years, range 18 to 29 years, height; 174.0 ± 5.6 cm, weight; 68.8 ± 13.5 kg) were randomly assigned to an interval training group or a control group. Interval training was conducted once weekly for 3 months. Each session consisted of three bouts of bicycle ergometer exercise at 80% maximum work rate until volitional fatigue. Before (baseline) and after the 3-month intervention, incremental exercise test was performed on a bicycle ergometer for determination of ventilatory threshold (VT), RCP, and peak oxygen consumption (V̇O 2 peak). The training program resulted in significant increases of V̇O 2 peak (+ 14%, p < 0.001, η p 2 = 0.437), oxygen consumption (V̇O 2) at VT (+ 18%, p < 0.001, η p 2 = 0.749) and RCP (+ 15%, p = 0.03, η p 2 = 0.239) during incremental exercise test in the training group. Furthermore, a significant positive correlation was observed between the increase in V̇O 2 peak and increase in V̇O 2 at RCP after intervention (r = 0.87, p = 0.002) in the training group. Tidal volumes at VT (p = 0.04, η p 2 = 0.270) and RCP (p = 0.01, η p 2 = 0.370) also increased significantly after intervention compared to baseline. Low-frequency severe-intensity interval training induced a shift in RCP toward higher work rate accompanied by higher tidal volume during incremental exercise test.
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Affiliation(s)
- Hidehiro Nakahara
- Graduate School of Health Sciences, Morinomiya University of Medical Sciences, Osaka, Japan
| | - Shin-Ya Ueda
- Department of Physical Education, Faculty of Education, Gifu University, Gifu, Japan
| | - Tadayoshi Miyamoto
- Graduate School of Human Environment, Faculty of Sport and Health Sciences, Osaka Sangyo University, Osaka, Japan
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Goh J, Menke W, Herrick LP, Campbell MS, Abel MG, Fleenor BS, Bergstrom HC. Examination of Curcumin and Fenugreek Soluble Fiber Supplementation on Submaximal and Maximal Aerobic Performance Indices. J Funct Morphol Kinesiol 2020; 5:jfmk5020034. [PMID: 33467250 PMCID: PMC7739318 DOI: 10.3390/jfmk5020034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/25/2020] [Accepted: 05/28/2020] [Indexed: 11/19/2022] Open
Abstract
UNLABELLED This study examined the effects of curcumin and fenugreek soluble fiber supplementation on the ventilatory threshold (VT) and peak oxygen consumption ( V ˙ O2 peak). METHODS Forty-five untrained men and women were randomly assigned to one of three supplementation groups: placebo (PLA, n = 13), 500 mg·day-1 CurQfen® (CUR, n = 14), or 300 mg·day-1 fenugreek soluble fiber (FEN, n = 18). Participants completed a maximal graded exercise test on a cycle ergometer to determine the VT and V ˙ O2 peak before (PRE) and after (POST) 28 days of daily supplementation. Separate, one-way analyses of covariance (ANCOVAs) were used to examine the between-group differences for adjusted POST VT and V ˙ O2 peak values, covaried for the respective PRE-test values. RESULTS The adjusted POST VT V ˙ O2 values for the CUR (mean ± SD = 1.593 ± 0.157 L·min-1) and FEN (1.597 ± 0.157 L·min-1) groups were greater than (p = 0.039 and p = 0.025, respectively) the PLA (1.465 ± 0.155 L·min-1) group, but the FEN and CUR groups were not different (p = 0.943). There were no differences in the adjusted V ˙ O2 peak values (F = 0.613, p = 0.547) among groups. CONCLUSION These findings indicated that fenugreek soluble fiber was responsible for the improvements in the submaximal performance index for both CUR and FEN groups.
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Affiliation(s)
- Jensen Goh
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40506, USA; (J.G.); (W.M.); (L.P.H.); (M.S.C.); (M.G.A.)
| | - Walter Menke
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40506, USA; (J.G.); (W.M.); (L.P.H.); (M.S.C.); (M.G.A.)
| | - Lauren P. Herrick
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40506, USA; (J.G.); (W.M.); (L.P.H.); (M.S.C.); (M.G.A.)
| | - Marilyn S. Campbell
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40506, USA; (J.G.); (W.M.); (L.P.H.); (M.S.C.); (M.G.A.)
| | - Mark G. Abel
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40506, USA; (J.G.); (W.M.); (L.P.H.); (M.S.C.); (M.G.A.)
| | | | - Haley C. Bergstrom
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40506, USA; (J.G.); (W.M.); (L.P.H.); (M.S.C.); (M.G.A.)
- Correspondence:
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Mitchell BL, Davison K, Parfitt G, Spedding S, Eston RG. Physiological and Perceived Exertion Responses during Exercise: Effect of β-blockade. Med Sci Sports Exerc 2019; 51:782-791. [PMID: 30439785 DOI: 10.1249/mss.0000000000001845] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE This study investigated the effect of β-blockade on physiological and perceived exertion (RPE) responses during incremental treadmill exercise. METHODS Sixteen healthy participants (n = 8 men; age, 25.3 ± 4.6 yr) performed a maximal treadmill exercise test after ingestion of 100 mg metoprolol or placebo, with a double-blind, randomized, and counterbalanced design. Heart rate (HR), ventilatory, and gas exchange variables were measured continuously, and participants reported RPE at the end of each minute. Physiological and RPE responses during each condition were compared at the ventilatory threshold (VT), respiratory compensation point, and at maximal exercise using repeated-measures ANOVA. Linear regression modeled relationships between perceived exertion and physiological variables. RESULTS The HR and V˙O2 at the VT, respiratory compensation point, and maximal exercise were all significantly lower after β-blockade (P < 0.05). However, when standardized to within condition peak values, differences were no longer significant. The RPE associated with VT was higher after β-blockade (12.9 ± 1.0 vs 12.3 ± 1.2, P < 0.05) but lower at maximal exercise (19.1 ± 0.6 vs 19.4 ± 0.5, P < 0.05). Increases in RPE relative to HR were greater after β-blockade and remained significant when expressed relative to peak HR. There was no difference in the growth of the relationship between RPE and V˙O2 across conditions, although the origin of the relationship was higher with β-blockade. CONCLUSIONS Although β-blockade resulted in a significant reduction in exercising HR and V˙O2, the RPE for a given relative intensity remained unchanged. The relationship between RPE and V˙O2 was not affected by β-blockade. The results provide evidence that RPE is a useful and reliable measure for exercise testing and prescription in patients prescribed β-blockade therapy.
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Affiliation(s)
- Braden L Mitchell
- Alliance for Research in Exercise, Nutrition and Activity, School of Health Sciences, University of South Australia, Adelaide, South Australia, AUSTRALIA
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Dykstra RM, Hanson NJ, Miller MG. Brain activity during self-paced vs. fixed protocols in graded exercise testing. Exp Brain Res 2019; 237:3273-3279. [PMID: 31650214 DOI: 10.1007/s00221-019-05669-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 10/05/2019] [Indexed: 10/25/2022]
Abstract
Electroencephalography research surrounding maximal exercise testing has been limited to male subjects. Additionally, studies have used open-looped protocols, meaning individuals do not know the exercise endpoint. Closed-loop protocols are often shown to result in optimal performance as self-pacing is permitted. The purpose of this study was to compare brain activity during open- and closed-loop maximal exercise protocols, and to determine if any sex differences are present. Twenty-seven subjects (12 males, ages 22.0 ± 2.5 years) participated in this study. A pre-assembled EEG sensor strip was used to collect brain activity from specific electrodes (F3/F4: dorsolateral prefrontal cortex, or dlPFC; and C3/Cz/C4: motor cortex, or MC). Alpha (8-12 Hz) and beta (12-30 Hz) frequency bands were analyzed. Subjects completed two maximal exercise tests on a cycle ergometer, separated by at least 48 h: a traditional, open-loop graded exercise test (GXT) and a closed-loop self-paced VO2max (SPV) test. Mixed model ANOVAs were performed to compare power spectral density (PSD) between test protocols and sexes. A significant interaction of time and sex was shown in the dlPFC for males, during the GXT only (p = 001), where a peak was reached and then a decrease was shown. A continuous increase was shown in the SPV. Sex differences in brain activity during exercise could be associated with inhibitory control, which is a function of the dlPFC. Knowledge of an exercise endpoint could be influential towards cessation of exercise and changes in cortical brain activity.
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Affiliation(s)
- Rachel M Dykstra
- Department of Human Performance and Health Education, Western Michigan University, 1903 W. Michigan Ave, Kalamazoo, MI, 49008, USA.
| | - Nicholas J Hanson
- Department of Human Performance and Health Education, Western Michigan University, 1903 W. Michigan Ave, Kalamazoo, MI, 49008, USA
| | - Michael G Miller
- Department of Human Performance and Health Education, Western Michigan University, 1903 W. Michigan Ave, Kalamazoo, MI, 49008, USA
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11
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Chacaroun S, Vega-Escamilla Y Gonzalez I, Flore P, Doutreleau S, Verges S. Physiological responses to hypoxic constant-load and high-intensity interval exercise sessions in healthy subjects. Eur J Appl Physiol 2018; 119:123-134. [PMID: 30315366 DOI: 10.1007/s00421-018-4006-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/03/2018] [Indexed: 12/11/2022]
Abstract
PURPOSE The aim of this study was to assess the acute cardiorespiratory as well as muscle and cerebral tissue oxygenation responses to submaximal constant-load (CL) and high-intensity interval (HII) cycling exercise performed in normoxia and in hypoxia at similar intensity, reproducing whole-body endurance exercise training sessions as performed in sedentary and clinical populations. METHODS Healthy subjects performed two CL (30 min, 75% of maximal heart rate, n = 12) and two HII (15 times 1-min high-intensity exercise-1-min passive recovery, n = 12) cycling exercise sessions in normoxia and in hypoxia [mean arterial oxygen saturation 76 ± 1% (clamped) during CL and 77 ± 5% (inspiratory oxygen fraction 0.135) during HII]. Cardiorespiratory and near-infrared spectroscopy parameters as well as the rate of perceived exertion were continuously recorded. RESULTS Power output was 21 ± 11% and 15% (according to protocol design) lower in hypoxia compared to normoxia during CL and HII exercise sessions, respectively. Heart rate did not differ between normoxic and hypoxic exercise sessions, while minute ventilation was higher in hypoxia during HII exercise only (+ 13 ± 29%, p < 0.05). Quadriceps tissue saturation index did not differ significantly between normoxia and hypoxia (CL 60 ± 8% versus 59 ± 5%; HII 59 ± 10% versus 56 ± 9%; p > 0.05), while prefrontal cortex deoxygenation was significantly greater in hypoxia during both CL (66 ± 4% versus 56 ± 6%) and HII (58 ± 5% versus 55 ± 5%; p < 0.05) sessions. The rate of perceived exertion did not differ between normoxic and hypoxic CL (2.4 ± 1.7 versus 2.9 ± 1.8) and HII (6.9 ± 1.4 versus 7.5 ± 0.8) sessions (p > 0.05). CONCLUSION This study indicates that at identical heart rate, reducing arterial oxygen saturation near 75% does not accentuate muscle deoxygenation during both CL and HII exercise sessions compared to normoxia. Hence, within these conditions, larger muscle hypoxic stress should not be expected.
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Affiliation(s)
- S Chacaroun
- HP2 Laboratory, INSERM U1042, UM Sports Pathologies, Hôpital Sud, Univ. Grenoble Alpes, Avenue Kimberley, 38 434, Echirolles, France
| | - I Vega-Escamilla Y Gonzalez
- HP2 Laboratory, INSERM U1042, UM Sports Pathologies, Hôpital Sud, Univ. Grenoble Alpes, Avenue Kimberley, 38 434, Echirolles, France
| | - P Flore
- HP2 Laboratory, INSERM U1042, UM Sports Pathologies, Hôpital Sud, Univ. Grenoble Alpes, Avenue Kimberley, 38 434, Echirolles, France
| | - S Doutreleau
- HP2 Laboratory, INSERM U1042, UM Sports Pathologies, Hôpital Sud, Univ. Grenoble Alpes, Avenue Kimberley, 38 434, Echirolles, France.,Grenoble Alpes University Hospital, Grenoble, France
| | - Samuel Verges
- HP2 Laboratory, INSERM U1042, UM Sports Pathologies, Hôpital Sud, Univ. Grenoble Alpes, Avenue Kimberley, 38 434, Echirolles, France. .,Grenoble Alpes University Hospital, Grenoble, France.
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12
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Qin R, Koike A, Nagayama O, Takayanagi Y, Wu L, Nishi I, Kato Y, Sato A, Yamashita T, Aonuma K, Ieda M. Clinical significance of respiratory compensation during exercise testing in cardiac patients. Biosci Trends 2018; 12:432-437. [PMID: 30101836 DOI: 10.5582/bst.2018.01165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Ventilation (VE) increases linearly with the increase of carbon dioxide output (VCO2) during cardiopulmonary exercise testing. VE-VCO2 slope rises in parallel with exercise intensity, reaches a turning point (called the RC point), then steepens because of respiratory compensation for lactic acidosis. While this RC point can be identified universally, it is undetectable in some patients. In this study we evaluated whether the respiratory compensation during exercise testing has clinical significance in cardiac patients. In total, 152 cardiac patients with a respiratory exchange ratio at peak exercise (peak R) of between 1.10 and 1.20 were enrolled. Cardiopulmonary parameters were compared between patients who manifested the RC point (n = 118) and those who did not (n = 34). The peak R did not significantly differ between these two groups. Compared to the patients without the RC point, those with the RC point had a higher oxygen uptake at peak exercise (peak VO2) (20.2 ± 5.3 vs 13.6 ± 3.4 mL/min/kg, p < 0.001), higher anaerobic threshold (AT) (12.4 ± 3.2 vs 9.2 ± 2.3 mL/min/kg, p < 0.001), and lower VE-VCO2 slope (31.7 ± 5.8 vs 37.8 ± 9.6, p = 0.001). Brain natriuretic peptide (BNP) tended to be lower in the patients with the RC point (175.4 ± 364.7 vs 327.9 ± 381.1 pg/mL, p = 0.067). Peak VO2, the marker of cardiopulmonary function, was found to be the independent predictor of the presence of the RC point. The present findings suggest that the phenomenon of respiratory compensation during heavy exercise indicates better cardiopulmonary function in cardiac patients within a prescribed range of effort.
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Affiliation(s)
- Rujie Qin
- Doctoral Program in Clinical Sciences, Graduate School of Comprehensive Human Science, University of Tsukuba
| | - Akira Koike
- Medical Science, Faculty of Medicine, University of Tsukuba.,Department of Cardiology, Faculty of Medicine, University of Tsukuba
| | | | - Yuta Takayanagi
- Department of Clinical Laboratory, University of Tsukuba Hospital
| | - Longmei Wu
- Department of Cardiology, Faculty of Medicine, University of Tsukuba
| | - Isao Nishi
- Department of Cardiology, Tsuchiura Clinical Education and Training Center, University of Tsukuba
| | | | - Akira Sato
- Department of Cardiology, Faculty of Medicine, University of Tsukuba
| | | | - Kazutaka Aonuma
- Department of Cardiology, Faculty of Medicine, University of Tsukuba
| | - Masaki Ieda
- Department of Cardiology, Faculty of Medicine, University of Tsukuba
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13
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Erylmaz SK, Kaynak K, Polat M, Aydoğan S. EFFECTS OF REPEATED SPRINT TRAINING ON ISOCAPNIC BUFFERING PHASE IN VOLLEYBALL PLAYERS. REV BRAS MED ESPORTE 2018. [DOI: 10.1590/1517-869220182404185842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
ABSTRACT Introduction: The region between the ventilatory threshold (VT) and respiratory compensation point (RCP) is defined as the isocapnic buffering (ICB) phase and represents a phase of compensation for exercise-induced metabolic acidosis. There is sparse literature examining the effects of physical training on ICB phase in athletes. Objectives: The purpose of this study was to examine the effects of a repeated sprint training program on the ICB phase of college volleyball players. Methods: Eighteen male volleyball players were randomly assigned to either an experimental group (n=9) or a control group (n=9) and followed a traditional volleyball training program three times per week for six weeks. The experimental group additionally performed a repeated sprint training protocol immediately before each volleyball training session. Before and after the 6-week training period, all participants performed an incremental treadmill test to determine VT, RCP, and maximal oxygen uptake (VO2max). The ICB phases were calculated as VO2 (ml/kg/min) and sprint speed (km/h). Results: The experimental group showed significant improvements in ICB phase, RCP, VO2max and maximal sprint speed after training (p<0.01). There were no significant changes in VT after training in the experimental group (p>0.05). None of these variables changed significantly in the control group (p>0.05). Conclusions: These findings indicate that repeated sprint training can enhance the ICB phase of volleyball players, which may be attributable to an improvement in buffering capacity leading to a shift in RCP towards higher intensities without any change in VT. The increase in the ICB phase may an important factor in terms of improvement in the high-intensity exercise tolerance of athletes. Level of Evidence II; Therapeutic studies - Investigating the results of treatment.
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14
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Salgado RM, Sheard AC, Vaughan RA, Parker DL, Schneider SM, Kenefick RW, McCormick JJ, Gannon NP, Van Dusseldorp TA, Kravitz LR, Mermier CM. Mitochondrial efficiency and exercise economy following heat stress: a potential role of uncoupling protein 3. Physiol Rep 2018; 5:5/3/e13054. [PMID: 28174343 PMCID: PMC5309567 DOI: 10.14814/phy2.13054] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 11/01/2016] [Accepted: 11/03/2016] [Indexed: 01/08/2023] Open
Abstract
Heat stress has been reported to reduce uncoupling proteins (UCP) expression, which in turn should improve mitochondrial efficiency. Such an improvement in efficiency may translate to the systemic level as greater exercise economy. However, neither the heat‐induced improvement in mitochondrial efficiency (due to decrease in UCP), nor its potential to improve economy has been studied. Determine: (i) if heat stress in vitro lowers UCP3 thereby improving mitochondrial efficiency in C2C12 myocytes; (ii) whether heat acclimation (HA) in vivo improves exercise economy in trained individuals; and (iii) the potential improved economy during exercise at altitude. In vitro, myocytes were heat stressed for 24 h (40°C), followed by measurements of UCP3, mitochondrial uncoupling, and efficiency. In vivo, eight trained males completed: (i) pre‐HA testing; (ii) 10 days of HA (40°C, 20% RH); and (iii) post‐HA testing. Pre‐ and posttesting consisted of maximal exercise test and submaximal exercise at two intensities to assess exercise economy at 1600 m (Albuquerque, NM) and 4350 m. Heat‐stressed myocytes displayed significantly reduced UCP3 mRNA expression and, mitochondrial uncoupling (77.1 ± 1.2%, P < 0.0001) and improved mitochondrial efficiency (62.9 ± 4.1%, P < 0.0001) compared to control. In humans, at both 1600 m and 4350 m, following HA, submaximal exercise economy did not change at low and moderate exercise intensities. Our findings indicate that while heat‐induced reduction in UCP3 improves mitochondrial efficiency in vitro, this is not translated to in vivo improvement of exercise economy at 1600 m or 4350 m.
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Affiliation(s)
- Roy M Salgado
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, New Mexico
| | - Ailish C Sheard
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, New Mexico.,School of Kinesiology and Nutritional Science, California State University Los Angeles, Los Angeles, California
| | - Roger A Vaughan
- Department of Exercise Science, High Point University, High Point, North Carolina
| | - Daryl L Parker
- Deparment of Kinesiology and Health Science, California State University Sacramento, Sacramento, California
| | - Suzanne M Schneider
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, New Mexico
| | - Robert W Kenefick
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - James J McCormick
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, New Mexico
| | - Nicholas P Gannon
- School of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Trisha A Van Dusseldorp
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, New Mexico.,Department of Exercise and Sport Management, Kennesaw State University, Kennesaw, Georgia
| | - Len R Kravitz
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, New Mexico
| | - Christine M Mermier
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, New Mexico
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15
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Robertson CV, Marino FE. Cerebral responses to exercise and the influence of heat stress in human fatigue. J Therm Biol 2017; 63:10-15. [PMID: 28010806 DOI: 10.1016/j.jtherbio.2016.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 10/06/2016] [Accepted: 10/06/2016] [Indexed: 10/20/2022]
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16
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Fan JL, Leiggener C, Rey F, Kayser B. Effect of inspired CO2 on the ventilatory response to high intensity exercise. Respir Physiol Neurobiol 2012; 180:283-8. [DOI: 10.1016/j.resp.2011.12.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 12/08/2011] [Accepted: 12/08/2011] [Indexed: 10/14/2022]
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17
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Evidence of break-points in breathing pattern at the gas-exchange thresholds during incremental cycling in young, healthy subjects. Eur J Appl Physiol 2011; 112:1067-76. [PMID: 21735217 DOI: 10.1007/s00421-011-2055-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 06/18/2011] [Indexed: 10/18/2022]
Abstract
The present study investigated whether 'break-points' in breathing pattern correspond to the first ([Formula: see text]) and second gas-exchange thresholds ([Formula: see text]) during incremental cycling. We used polynomial spline smoothing to detect accelerations and decelerations in pulmonary gas-exchange data, which provided an objective means of 'break-point' detection without assumption of the number and shape of said 'break-points'. Twenty-eight recreational cyclists completed the study, with five individuals excluded from analyses due to low signal-to-noise ratios and/or high risk of 'pseudo-threshold' detection. In the remaining participants (n = 23), two separate and distinct accelerations in respiratory frequency (f (R)) during incremental work were observed, both of which demonstrated trivial biases and reasonably small ±95% limits of agreement (LOA) for the [Formula: see text] (0.2 ± 3.0 ml O(2) kg(-1) min(-1)) and [Formula: see text] (0.0 ± 2.4 ml O(2) kg(-1) min(-1)), respectively. A plateau in tidal volume (V (T)) data near the [Formula: see text] was identified in only 14 individuals, and yielded the most unsatisfactory mean bias ±LOA of all comparisons made (-0.4 ± 5.3 ml O(2) kg(-1) min(-1)). Conversely, 18 individuals displayed V (T)-plateau in close proximity to the [Formula: see text] evidenced by a mean bias ± LOA of 0.1 ± 3.1 ml O(2) kg(-1) min(-1). Our findings suggest that both accelerations in f (R) correspond to the gas-exchange thresholds, and a plateau (or decline) in V (T) at the [Formula: see text] is a common (but not universal) feature of the breathing pattern response to incremental cycling.
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18
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The effect of a six-month training programme on the endurance and aerobic capacity parameters of adult women. Zdr Varst 2010. [DOI: 10.2478/v10152-010-0013-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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19
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Peltonen JE, Paterson DH, Shoemaker JK, DeLorey DS, duManoir GR, Petrella RJ, Kowalchuk JM. Cerebral and muscle deoxygenation, hypoxic ventilatory chemosensitivity and cerebrovascular responsiveness during incremental exercise. Respir Physiol Neurobiol 2009; 169:24-35. [DOI: 10.1016/j.resp.2009.08.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 08/26/2009] [Accepted: 08/26/2009] [Indexed: 10/20/2022]
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20
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Bhambhani Y, Malik R, Mookerjee S. Cerebral oxygenation declines at exercise intensities above the respiratory compensation threshold. Respir Physiol Neurobiol 2007; 156:196-202. [PMID: 17045853 DOI: 10.1016/j.resp.2006.08.009] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 08/21/2006] [Accepted: 08/22/2006] [Indexed: 12/27/2022]
Abstract
During incremental exercise PaCO2 and PETCO2 begin to decline at the respiratory compensation threshold (RCT-GEX). Since PaCO2 alters cerebral blood flow it was hypothesized that there would be a systematic decline in cerebral oxygenation (Cox) measured by near infrared spectroscopy above the RCT (RCT-NIRS). Cardiorespiratory and NIRS responses were simultaneously monitored from the left frontal lobe during incremental exercise in 17 men. All subjects showed a decline in Cox above the RCT-GEX with a 20-40 s delay. Significant differences (P<0.01) were observed between the RCT-GEX and RCT-NIRS for time (9.83 versus 10.39 min), power (198 versus 212 W) and oxygen uptake (2.31 versus 2.43 L min-1). Intra-class correlations for power and absolute VO2 were 0.97 and 0.98, respectively. Bland-Altman analysis revealed no outliers for any of the variables. The results suggested that the decrease in Cox observed above the RCT was most likely due to a reduction in cerebral blood flow mediated by a decline in PaCO2. This decline in Cox could reduce neuronal activation thereby limiting maximal exercise capacity in healthy subjects.
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Affiliation(s)
- Yagesh Bhambhani
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada.
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21
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Ogata H, Reyihan A, Yano T. Kinetics of Oxygenation in Inactive Forearm Muscle during Ramp Leg Cycling. ACTA ACUST UNITED AC 2004; 23:7-17. [PMID: 14757996 DOI: 10.2114/jpa.23.7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
This study was carried out to determine whether hemodynamics in inactive forearm muscle during ramp leg cycling is affected from the ventilatory threshold (VT) and respiratory compensation point (RCP), at which the rate of increase in ventilation (VE) against power output begins to increase abruptly. Change in hemodynamics was evaluated by change in oxygenation index (difference between concentrations of oxygenated hemoglobin and deoxygenated hemoglobin, HbD) measured using near-infrared spectrometry (NIRS). Each subject (n=9) performed 4-min constant-work-rate leg cycling and subsequent ramp leg cycling at an increasing rate of 10 watts.min(-1) in power output. The work rates at VT, RCP and peak oxygen uptake (VO(2 peak)) were 107 +/- 11, 172 +/- 21 and 206 +/- 20 watts, respectively. The rates of increase in VE between 10-watt leg cycling, VT, RCP and VO(2 peak) were 0.19 +/- 0.03, 0.44 +/- 0.07 and 1.32 +/- 0.47 l.min(-1).watts(-1), respectively. In one subject, HbD started to decrease during ramp exercise from the VT, and the rate of decrease increased at a high intensity of exercise. In eight subjects, although no decrease in HbD from the VT was observed, HbD showed a sudden drop at a high intensity of exercise. The work rate at which HbD began to decrease at a high intensity of exercise was 174 +/- 23 watts. This work rate was not significantly different from that at the RCP and was significantly correlated with that at the RCP (r=0.72, P<0.05). The results suggest that the abrupt increase in VE from the RCP affects hemodynamics, resulting in a decrease in HbD in inactive forearm muscle.
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Affiliation(s)
- Hisayoshi Ogata
- Laboratory of Exercise Physiology, Graduate School of Education, Hokkaido University, Japan.
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