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Imomnazarov K, Torrence SE, Lindgren CA. Reduced Plasma-Membrane Calcium ATPase Activity and Extracellular Acidification Trigger Presynaptic Homeostatic Potentiation at the Mouse Neuromuscular Junction. Neuroscience 2023; 532:103-112. [PMID: 37778690 DOI: 10.1016/j.neuroscience.2023.09.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 08/23/2023] [Accepted: 09/24/2023] [Indexed: 10/03/2023]
Abstract
At the vertebrate neuromuscular junction (NMJ), presynaptic homeostatic potentiation (PHP) refers to an increase in neurotransmitter release that restores the strength of synaptic transmission following a blockade of nicotinic acetylcholine receptors (nAChRs). Mechanisms informing the presynaptic terminal of the loss of postsynaptic receptivity remain poorly understood. Previous research at the mouse NMJ suggests that extracellular protons may function as a retrograde signal that triggers an upregulation of neurotransmitter output (measured by quantal content, QC) through the activation of acid-sensing ion channels (ASICs). We further investigated the pH-dependency of PHP in an ex-vivo mouse muscle preparation. We observed that increasing the buffering capacity of the perfusion saline with HEPES abolishes PHP and that acidifying the saline from pH 7.4 to pH 7.2-7.1 increases QC, demonstrating the necessity and sufficiency of extracellular acidification for PHP. We then sought to uncover how the blockade of nAChRs leads to the pH decrease. Plasma-membrane calcium ATPase (PMCA), a calcium-proton antiporter, is known to alkalize the synaptic cleft following neurotransmission in a calcium-dependent manner. We hypothesize that since nAChR blockade reduces postsynaptic calcium entry, it also reduces the alkalizing activity of the PMCA, thereby causing acidosis, ASIC activation, and QC upregulation. In line with this hypothesis, we found that pharmacological inhibition of the PMCA with carboxyeosin induces QC upregulation and that this effect requires functional ASICs. We also demonstrated that muscles pre-treated with carboxyeosin fail to generate PHP. These findings suggest that reduced PMCA activity causes presynaptic homeostatic potentiation by activating ASICs at the mouse NMJ.
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Affiliation(s)
| | - Sarah E Torrence
- Department of Biology, Grinnell College, Grinnell, IA 50112, United States
| | - Clark A Lindgren
- Department of Biology, Grinnell College, Grinnell, IA 50112, United States.
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Salah H, El-Gazzar RM, Abd El-Wahab EW, Charl F. Oxidative stress and adverse cardiovascular effects among professional divers in Egypt. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2023; 20:159-169. [PMID: 36716173 DOI: 10.1080/15459624.2023.2173364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Professional divers are exposed to unique multifactorial hazards in their working environment and adverse cardiovascular effects such as ischemia, arrhythmia, stroke, and death are associated with professional diving. Cardiovascular events are aggravated by diving-induced oxidative stress and account for one-fourth of diving fatalities. This study aimed to measure oxidative and cardiovascular stress in a group of professional divers in Alexandria, Egypt using a panel of biomarkers. A comparative cross-sectional study was conducted between June 2017 and May 2018 at the General Naval Hospital in Alexandria. A total of 50 professional divers and a comparison group of 50 marine seafarers sharing similar maritime environments were enrolled in the study. Participants were clinically evaluated by electrocardiography (ECG) and plasma measurement of trace metals (Fe+, Cu+, and Zn+), electrolytes (Na+, K+, Ca+), and oxidative stress biomarkers (OSBMs; MDA, TAS, GST, GSH, GR, GPx, SOD, and CAT). Significant ECG abnormalities including short corrected QT interval, sinus bradycardia, left ventricular hypertrophy, early repolarization, first-degree heart block, and intraventricular conduction defect were identified among divers. Biochemical analyses revealed high mean levels of FBG [89.0 ± 12.46 vs. 100.5 ± 29.03 mg/dl], LDH-C [41.46 ± 4.01 vs. 39.34 ± 4.34 mg/dl], electrolyte imbalance [higher Na+ (9.44 ± 0.52 vs. 9.19 ± 0.60 mmol/L), and lower Ca+ (141.72 ± 3.53 and 143.26 ± 3.99 mmol/L)], disturbed trace metals [Fe+ and Zn+ (101.1 ± 38.17 vs. 147.6 ± 38.08 and 85.52 ± 27.37 vs. 116.6 ± 21.95 µm/dl, respectively), higher Cu+ (271.3 ± 75.01 vs. 100.8 ± 30.20 µm/dl)], and higher OSBMs (high MDA and reduced CAT, GPx, GSH, GR, and GST enzyme levels) among professional divers compared to the marine seafarers (t-test p < 0.05). Oxidative stress and trace metal imbalance are associated with the pathophysiology of cardiovascular disease; this association, together with electrophysiological changes of ECG may serve as biomarkers for cardiovascular risk assessment in diver periodic medical examinations.
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Affiliation(s)
- Hanie Salah
- Department of Occupational Health and Industrial Medicine, High Institute of Public Health, Alexandria University, Alexandria, Egypt
| | - Ragaa M El-Gazzar
- Department of Occupational Health and Industrial Medicine, High Institute of Public Health, Alexandria University, Alexandria, Egypt
| | - Ekram W Abd El-Wahab
- Department of Tropical Health, High Institute of Public Health, Alexandria University, Alexandria, Egypt
| | - Fahmy Charl
- Department of Occupational Health and Industrial Medicine, High Institute of Public Health, Alexandria University, Alexandria, Egypt
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Costa GP, Camacho-Cardenosa A, Brazo-Sayavera J, Viliod MCDL, Camacho-Cardenosa M, Foresti YF, de Carvalho CD, Merellano-Navarro E, Papoti M, Trapé ÁA. Effectiveness, implementation, and monitoring variables of intermittent hypoxic bicycle training in patients recovered from COVID-19: The AEROBICOVID study. Front Physiol 2022; 13:977519. [PMID: 36406995 PMCID: PMC9667939 DOI: 10.3389/fphys.2022.977519] [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: 06/24/2022] [Accepted: 10/17/2022] [Indexed: 11/29/2022] Open
Abstract
Hypoxic exposure is safely associated with exercise for many pathological conditions, providing additional effects on health outcomes. COVID-19 is a new disease, so the physiological repercussions caused by exercise in affected patients and the safety of exposure to hypoxia in these conditions are still unknown. Due to the effects of the disease on the respiratory system and following the sequence of AEROBICOVID research work, this study aimed to evaluate the effectiveness, tolerance and acute safety of 24 bicycle training sessions performed under intermittent hypoxic conditions through analysis of peripheral oxyhemoglobin saturation (SpO2), heart rate (HR), rate of perceived exertion (RPE), blood lactate concentration ([La-]) and symptoms of acute mountain sickness in patients recovered from COVID-19. Participants were allocated to three training groups: the normoxia group (GN) remained in normoxia (inspired fraction of O2 (FiO2) of ∼20.9%, a city with 526 m altitude) for the entire session; the recovery hypoxia group (GHR) was exposed to hypoxia (FiO2 ∼13.5%, corresponding to 3,000 m altitude) all the time except during the effort; the hypoxia group (GH) trained in hypoxia (FiO2 ∼13.5%) throughout the session. The altitude simulation effectively reduced SpO2 mean with significant differences between groups GN, GHR, and GH, being 96.9(1.6), 95.1(3.1), and 87.7(6.5), respectively. Additionally, the proposed exercise and hypoxic stimulus was well-tolerated, since 93% of participants showed no or moderate acute mountain sickness symptoms; maintained nearly 80% of sets at target heart rate; and most frequently reporting session intensity as an RPE of "3" (moderate). The internal load calculation, analyzed through training impulse (TRIMP), calculated using HR [TRIMPHR = HR * training volume (min)] and RPE [TRIMPRPE = RPE * training volume (min)], showed no significant difference between groups. The current strategy effectively promoted the altitude simulation and monitoring variables, being well-tolerated and safely acute exposure, as the low Lake Louise scores and the stable HR, SpO2, and RPE values showed during the sessions.
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Affiliation(s)
- Gabriel Peinado Costa
- School of Physical Education and Sport of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Alba Camacho-Cardenosa
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Javier Brazo-Sayavera
- Department of Sports and Computer Science, Universidad Pablo de Olavide, Seville, Spain,Polo de Desarrollo Universitario EFISAL, Centro Universitario Regional Noreste, Universidad de la República, Rivera, Uruguay
| | | | - Marta Camacho-Cardenosa
- Clinical Management Unit of Endocrinology and Nutrition - GC17, Maimónides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofía University Hospital, Córdoba, Spain
| | - Yan Figueiredo Foresti
- School of Physical Education and Sport of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Brazil
| | | | - Eugenio Merellano-Navarro
- Departamento de Ciencias de la Actividad Física, Facultad de Ciencias de la Educación, Universidad Católica del Maule, Talca, Chile
| | - Marcelo Papoti
- School of Physical Education and Sport of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Brazil,Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Átila Alexandre Trapé
- School of Physical Education and Sport of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Brazil,*Correspondence: Átila Alexandre Trapé,
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Salah H, El-gazzar RM, Abd El-wahab EW, Charl F. Oxidative and cardiovascular stress among professional divers in Egypt.. [DOI: 10.1101/2022.10.20.22281338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
AbstractObjectivesProfessional divers are exposed to unique multifactorial hazards in their working environment and cardiovascular effects are tremendous. Cardiovascular events are aggravated by diving-induced oxidative stress and account for one fourth of diving fatalities. The aim of this study was to assess the oxidative and cardiovascular stress in a group of professional divers in Alexandria, Egypt using a panel of biomarkers.MethodsA comparative cross-sectional study was conducted between June 2017 and May 2018 at the General Naval Hospital in Alexandria. We recruited 50 professional divers (n=50) and a comparison group of 50 marine seafarers sharing similar maritime environments. Participants were clinically evaluated by electrocardiography (ECG) and assessment of some trace metals (Fe+, Cu+and Zn+) and oxidative stress biomarkers (OSBMs; MDA, TAS, GST, GSH, GR, GPx, SOD and CAT).Results: Significant ECG abnormalities including short corrected QT interval, sinus bradycardia, left ventricular hypertrophy, early repolarization, 1stdegree heart block, intraventricular conduction defect were obvious among divers. The mean levels of FBG, LDH-C, Na+, Ca+, trace metals and OSBMs were significantly higher among professional divers compared to the marine seafarers (p< 0.5).ConclusionThe risk of CVD in professional divers is alarmingly high and possibly contributed by OS. Including cardiovascular risk assessment in divers’ periodic examinations is of utmost importance.
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Hohenauer E, Freitag L, Herten M, Siallagan J, Pollock E, Taube W, Clijsen R. The Methodological Quality of Studies Investigating the Acute Effects of Exercise During Hypoxia Over the Past 40 years: A Systematic Review. Front Physiol 2022; 13:919359. [PMID: 35784889 PMCID: PMC9243659 DOI: 10.3389/fphys.2022.919359] [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: 04/13/2022] [Accepted: 05/09/2022] [Indexed: 11/25/2022] Open
Abstract
Exercise under hypoxia and the physiological impact compared to normoxia or hypoxia has gained attention in the last decades. However, methodological quality assessment of articles in this area is lacking in the literature. Therefore, this article aimed to evaluate the methodologic quality of trials studying exercise under hypoxia. An electronic search was conducted until December 2021. The search was conducted in PubMed, CENTRAL, and PEDro using the PICO model. (P) Participants had to be healthy, (I) exercise under normobaric or hypobaric hypoxia had to be (C) compared to exercise in normoxia or hypoxia on (O) any physiological outcome. The 11-item PEDro scale was used to assess the methodological quality (internal validity) of the studies. A linear regression model was used to evaluate the evolution of trials in this area, using the total PEDro score of the rated trials. A total of n = 81 studies met the inclusion criteria and were processed in this study. With a mean score of 5.1 ± 0.9 between the years 1982 and 2021, the mean methodological quality can be described as “fair.” Only one study reached the highest score of 8/10, and n = 2 studies reached the lowest observed value of 3/10. The linear regression showed an increase of the PEDro score of 0.1 points per decade. A positive and small tendency toward increased methodologic quality was observed. The current results demonstrate that a positive and small tendency can be seen for the increase in the methodological quality in the field of exercise science under hypoxia. A “good” methodological quality, reaching a PEDro score of 6 points can be expected in the year 2063, using a linear regression model analysis. To accelerate this process, future research should ensure that methodological quality criteria are already included during the planning phase of a study.
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Affiliation(s)
- Erich Hohenauer
- Rehabilitation and Exercise Science Laboratory (RES Lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland
- International University of Applied Sciences THIM, Landquart, Switzerland
- Department of Neurosciences and Movement Science, University of Fribourg, Fribourg, Switzerland
- Department of Movement and Sport Sciences, Vrije Universiteit Brussel, Brussels, Belgium
- *Correspondence: Erich Hohenauer,
| | - Livia Freitag
- Rehabilitation and Exercise Science Laboratory (RES Lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland
| | - Miriam Herten
- Rehabilitation and Exercise Science Laboratory (RES Lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland
| | - Julia Siallagan
- Rehabilitation and Exercise Science Laboratory (RES Lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland
| | - Elke Pollock
- Department of Physiotherapy, Zurich University of Applied Sciences, Zurich, Switzerland
| | - Wolfgang Taube
- Department of Neurosciences and Movement Science, University of Fribourg, Fribourg, Switzerland
| | - Ron Clijsen
- Rehabilitation and Exercise Science Laboratory (RES Lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland
- International University of Applied Sciences THIM, Landquart, Switzerland
- Department of Movement and Sport Sciences, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Health, Bern University of Applied Sciences, Berne, Switzerland
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Hebisz R, Hebisz P, Danek N, Michalik K, Zatoń M. Predicting Changes in Maximal Oxygen Uptake in Response to Polarized Training (Sprint Interval Training, High-Intensity Interval Training, and Endurance Training) in Mountain Bike Cyclists. J Strength Cond Res 2022; 36:1726-1730. [PMID: 32341248 DOI: 10.1519/jsc.0000000000003619] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Hebisz, R, Hebisz, P, Danek, N, Michalik, K, and Zatoń, M. Predicting changes in maximal oxygen uptake in response to polarized training (sprint interval training, high-intensity interval training, and endurance training) in mountain bike cyclists. J Strength Cond Res 36(6): 1726-1730, 2022-The aim of this study was to determine the predictors of change in maximal oxygen uptake (ΔV̇o2max) in response to a polarized training program. Twenty well-trained mountain bike cyclists completed an 8-week intervention of sprint interval training (SIT) (8-16 30-second maximal sprints), high-intensity interval training (4-6 bouts at 85-95% maximal aerobic power), and endurance training (2-3 hours cycling at 70-80% power at the ventilatory threshold). An incremental exercise test was performed to determine preintervention and postintervention maximal oxygen uptake (V̇o2max) and maximal pulmonary ventilation (VEmax) normalized to lean body mass (LBM). The frequency and time domain of heart rate variability (HRV) was also determined during recovery after moderate warm-up in the first and last SIT. Training status was quantified as the total distance cycled in the previous year. V̇o2max, VEmax, and the root mean square of the successive differences of normal-to-normal time interval between heartbeats (RMSSD), which is the time domain of HRV all increased significantly. Multiple significant correlations were observed between ΔV̇o2max and training status and baseline measures of VEmax·LBM-1, RMSSD, and V̇o2max·LBM-1 and a regression equation was developed (r = 0.87, r2 = 0.76; p = 0.0001). The change in V̇o2max in response to polarized training can be predicted with high accuracy based on several measurable variables.
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Affiliation(s)
- Rafał Hebisz
- Department of Physiology and Biochemistry, University School of Physical Education, Wroclaw, Poland
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Effects of Resistance Training in Hypobaric vs. Normobaric Hypoxia on Circulating Ions and Hormones. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19063436. [PMID: 35329124 PMCID: PMC8949299 DOI: 10.3390/ijerph19063436] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/10/2022] [Accepted: 03/12/2022] [Indexed: 11/25/2022]
Abstract
Hypobaric hypoxia (HH) seems to lead to different responses compared to normobaric hypoxia (NH) during physical conditioning. The aim of the study was to analyze the hormonal and circulating ion responses after performing high-intensity resistance training with different inter-set rest under HH and NH condition. Sixteen male volunteers were randomly divided into two training groups. Each group completed two counterbalanced resistance training sessions (three sets × ten repetitions, remaining two repetitions in reserve), with both one- and two-minute inter-set rest, under HH and NH. Blood samples were obtained to determine hormones and circulating ions (Ca2+, Pi, and HCO3−) at baseline and after training sessions (5, 10, and 30 min). Resistance training with one-minute rest caused greater hormonal stress than with two-minute rest in cortisol and growth hormone, although the hypoxic environmental condition did not cause any significant alterations in these hormones. The short inter-set rest also caused greater alterations in HCO3− and Pi than the longer rest. Additionally, higher levels of Ca2+ and Pi, and lower levels of HCO3−, were observed after training in HH compared to NH. Metabolic and physiological responses after resistance training are mediated by inter-set rest intervals and hypoxic environmental condition. According to the alterations observed in the circulating ions, HH could cause greater muscular fatigue and metabolic stress than NH.
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Metabolic, Cardiac, and Hemorheological Responses to Submaximal Exercise under Light and Moderate Hypobaric Hypoxia in Healthy Men. BIOLOGY 2022; 11:biology11010144. [PMID: 35053141 PMCID: PMC8772706 DOI: 10.3390/biology11010144] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/11/2022] [Accepted: 01/13/2022] [Indexed: 11/28/2022]
Abstract
Simple Summary The lower atmospheric partial pressure of oxygen under hypobaric hypoxia decreases oxygen saturation and arteriovenous oxygen difference. Exercise under hypoxia decreases arterial oxygen saturation, which reduces the ability to deliver oxygen to active muscles and consequently worsens aerobic capacity and exercise performance. Previous studies on metabolic and cardiac responses to submaximal exercise under hypoxia have been well documented, but information on hemorheological responses is relatively insufficient. In this regard, a review of hemorheological responses to exercise under hypoxia could provide further information on reduced aerobic capacity and exercise performance caused by acute hypoxia. We conducted a randomized crossover trial to compare the effects of acute exercise under light and moderate hypobaric hypoxia versus normoxia on metabolic parameters, cardiac function, and hemorheological properties in healthy men. The main findings of our study revealed that endurance submaximal exercise under light (596 mmHg, simulated 2000 m) and moderate (526 mmHg, simulated 3000 m) hypoxia induced greater metabolic and cardiac responses than exercise under normoxia. However, exercise under hypobaric hypoxia did not affect hemorheological properties, including erythrocyte deformability and aggregation. These results can be used as basic data for understanding hemorheological responses in light and moderate hypobaric hypoxia. Abstract We compared the effects of metabolic, cardiac, and hemorheological responses to submaximal exercise under light hypoxia (LH) and moderate hypoxia (MH) versus normoxia (N). Ten healthy men (aged 21.3 ± 1.0 years) completed 30 min submaximal exercise corresponding to 60% maximal oxygen uptake at normoxia on a cycle ergometer under normoxia (760 mmHg), light hypoxia (596 mmHg, simulated 2000 m altitude), and moderate hypoxia (526 mmHg, simulated 3000 m altitude) after a 30 min exposure in the respective environments on different days, in a random order. Metabolic parameters (oxygen saturation (SPO2), minute ventilation, oxygen uptake, carbon dioxide excretion, respiratory exchange ratio, and blood lactate), cardiac function (heart rate (HR), stroke volume, cardiac output, and ejection fraction), and hemorheological properties (erythrocyte deformability and aggregation) were measured at rest and 5, 10, 15, and 30 min after exercise. SPO2 significantly reduced as hypoxia became more severe (MH > LH > N), and blood lactate was significantly higher in the MH than in the LH and N groups. HR significantly increased in the MH and LH groups compared to the N group. There was no significant difference in hemorheological properties, including erythrocyte deformability and aggregation. Thus, submaximal exercise under light/moderate hypoxia induced greater metabolic and cardiac responses but did not affect hemorheological properties.
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Płoszczyca K, Chalimoniuk M, Przybylska I, Czuba M. Effects of Short-Term Phosphate Loading on Aerobic Capacity under Acute Hypoxia in Cyclists: A Randomized, Placebo-Controlled, Crossover Study. Nutrients 2022; 14:236. [PMID: 35057416 PMCID: PMC8778537 DOI: 10.3390/nu14020236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/01/2022] [Accepted: 01/03/2022] [Indexed: 02/04/2023] Open
Abstract
The aim of this study was to evaluate the effects of sodium phosphate (SP) supplementation on aerobic capacity in hypoxia. Twenty-four trained male cyclists received SP (50 mg·kg-1 of FFM/day) or placebo for six days in a randomized, crossover study, with a three-week washout period between supplementation phases. Before and after each supplementation phase, the subjects performed an incremental exercise test to exhaustion in hypoxia (FiO2 = 16%). Additionally, the levels of 2,3-diphosphoglycerate (2,3-DPG), hypoxia-inducible factor 1 alpha (HIF-1α), inorganic phosphate (Pi), calcium (Ca), parathyroid hormone (PTH) and acid-base balance were determined. The results showed that phosphate loading significantly increased the Pi level by 9.0%, whereas 2,3-DPG levels, hemoglobin oxygen affinity, buffering capacity and myocardial efficiency remained unchanged. The aerobic capacity in hypoxia was not improved following SP. Additionally, our data revealed high inter-individual variability in response to SP. Therefore, the participants were grouped as Responders and Non-Responders. In the Responders, a significant increase in aerobic performance in the range of 3-5% was observed. In conclusion, SP supplementation is not an ergogenic aid for aerobic capacity in hypoxia. However, in certain individuals, some benefits can be expected, but mainly in athletes with less training-induced central and/or peripheral adaptation.
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Affiliation(s)
- Kamila Płoszczyca
- Department of Kinesiology, Institute of Sport, 01-982 Warsaw, Poland
| | - Małgorzata Chalimoniuk
- Department of Physiotherapy, Faculty of Physical Education and Health in Biala Podlaska, Jozef Pilsudski University of Physical Education in Warsaw, 21-500 Biala Podlaska, Poland
| | - Iwona Przybylska
- Department of Physiotherapy, Faculty of Physical Education and Health in Biala Podlaska, Jozef Pilsudski University of Physical Education in Warsaw, 21-500 Biala Podlaska, Poland
| | - Miłosz Czuba
- Department of Kinesiology, Institute of Sport, 01-982 Warsaw, Poland
- Faculty of Rehabilitation, Jozef Pilsudski University of Physical Education in Warsaw, 00-968 Warsaw, Poland
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Rivera PM, Proppe CE, Beltran E, Hill EC. Acute Effects of Local Ischemic Hypoxia and Systemic Hypoxemia on Neuromuscular and Cognitive Function. High Alt Med Biol 2021; 23:18-25. [PMID: 34936812 DOI: 10.1089/ham.2021.0096] [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: 11/13/2022] Open
Abstract
Rivera, Paola M., Chris E. Proppe, Esther Beltran, and Ethan C. Hill. Acute effects of local ischemic hypoxia and systemic hypoxemia on neuromuscular and cognitive function. High Alt Med Biol. 00:000-000, 2021. Background: The application of blood flow restriction (BFR) induces local ischemic hypoxia within the muscle(s) distal to the restriction device. Systemic hypoxemia via oxygen or barometric pressure manipulation achieves whole-body hypoxia and thus may be a more potent exercise adjunct than BFR. Therefore, the purpose of this study was to examine the acute effects of local ischemic hypoxia versus systemic hypoxemia on maximal voluntary isometric contraction (MVIC) torque, electromyographic amplitude (EMG AMP), EMG mean power frequency (MPF), and cognition. Materials and Methods: Twelve recreationally trained women (mean age ± standard deviation = 21 ± 1.6 years) performed 75 submaximal (1 × 30, 3 × 15) unilateral leg extension muscle actions under normoxia, local ischemic hypoxia, and systemic hypoxemia. Before and immediately after the 75 repetitions, MVIC muscle actions were performed, and surface EMG was simultaneously assessed from the vastus lateralis. Cognitive function was assessed immediately after each exercise using the Automated Neuropsychological Assessment Metrics (ANAM). Separate repeated-measures analyses of variance (ANOVAs) were performed to examine changes in MVIC, reaction time, EMG AMP, and EMG MPF responses during the MVIC muscle actions. Results: There were no significant (p = 0.21-0.953) Condition × Time interactions for MVIC, EMG AMP, or EMG MPF but a significant (p < 0.001-0.005) main effect for the Time collapsed across Condition for MVIC torque (pretest 238.8 ± 19.5, posttest 212.7 ± 20.1 Nm) and EMG MPF (88.5% ± 1.4% of pretest). There were no significant (p = 0.503) differences in reaction time among Conditions. Conclusions: The findings of the present study suggest that all three conditions elicited comparable acute changes in performance as assessed by MVIC torque that were associated with no changes in muscle activation but decrease in action potential conduction velocity. Therefore, the application of local ischemic hypoxia or systemic hypoxemia during low-load resistance exercise can be used to elicit similar acute physiological responses and not adversely affect cognitive function relative to nonhypoxic conditions.
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Affiliation(s)
- Paola M Rivera
- Exercise Physiology Intervention and Collaboration Laboratory, Division of Kinesiology, School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, Florida, USA
| | - Christopher E Proppe
- Exercise Physiology Intervention and Collaboration Laboratory, Division of Kinesiology, School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, Florida, USA
| | - Esther Beltran
- Florida Space Institute, University of Central Florida, Orlando, Florida, USA
| | - Ethan C Hill
- Exercise Physiology Intervention and Collaboration Laboratory, Division of Kinesiology, School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, Florida, USA.,Florida Space Institute, University of Central Florida, Orlando, Florida, USA
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11
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Newbury JW, Cole M, Kelly AL, Chessor RJ, Sparks SA, McNaughton LR, Gough LA. The time to peak blood bicarbonate (HCO3-), pH, and the strong ion difference (SID) following sodium bicarbonate (NaHCO3) ingestion in highly trained adolescent swimmers. PLoS One 2021; 16:e0248456. [PMID: 34197456 PMCID: PMC8248647 DOI: 10.1371/journal.pone.0248456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 06/17/2021] [Indexed: 11/18/2022] Open
Abstract
The timing of sodium bicarbonate (NaHCO3) supplementation has been suggested to be most optimal when coincided with a personal time that bicarbonate (HCO3–) or pH peaks in the blood following ingestion. However, the ergogenic mechanisms supporting this ingestion strategy are strongly contested. It is therefore plausible that NaHCO3 may be ergogenic by causing beneficial shifts in the strong ion difference (SID), though the time course of this blood acid base balance variable is yet to be investigated. Twelve highly trained, adolescent swimmers (age: 15.9 ± 1.0 years, body mass: 65.3 ± 9.6 kg) consumed their typical pre-competition nutrition 1–3 hours before ingesting 0.3 g∙kg BM-1 NaHCO3 in gelatine capsules. Capillary blood samples were then taken during seated rest on nine occasions (0, 60, 75, 90, 105, 120, 135, 150, 165 min post-ingestion) to identify the time course changes in HCO3–, pH, and the SID. No significant differences were found in the time to peak of each blood measure (HCO3–: 130 ± 35 min, pH: 120 ± 38 min, SID: 98 ± 37 min; p = 0.08); however, a large effect size was calculated between time to peak HCO3– and the SID (g = 0.88). Considering that a difference between time to peak blood HCO3– and the SID was identified in adolescents, future research should compare the ergogenic effects of these two individualized NaHCO3 ingestion strategies compared to a traditional, standardized approach.
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Affiliation(s)
- Josh W. Newbury
- Human Performance and Health Research Group, Centre for Life and Sport Sciences (CLaSS), Department of Sport and Exercise, Birmingham City University, Birmingham, United Kingdom
| | - Matthew Cole
- Human Performance and Health Research Group, Centre for Life and Sport Sciences (CLaSS), Department of Sport and Exercise, Birmingham City University, Birmingham, United Kingdom
| | - Adam L. Kelly
- Human Performance and Health Research Group, Centre for Life and Sport Sciences (CLaSS), Department of Sport and Exercise, Birmingham City University, Birmingham, United Kingdom
| | - Richard J. Chessor
- Sports Science and Sports Medicine Team, British Swimming, Loughborough, Leicestershire, United Kingdom
| | - S. Andy Sparks
- Sports Nutrition and Performance Research Group, Department of Sport and Physical Activity, Edge Hill University, Ormskirk, United Kingdom
- * E-mail:
| | - Lars R. McNaughton
- Sports Nutrition and Performance Research Group, Department of Sport and Physical Activity, Edge Hill University, Ormskirk, United Kingdom
| | - Lewis A. Gough
- Human Performance and Health Research Group, Centre for Life and Sport Sciences (CLaSS), Department of Sport and Exercise, Birmingham City University, Birmingham, United Kingdom
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12
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Płoszczyca K, Czuba M, Chalimoniuk M, Gajda R, Baranowski M. Red Blood Cell 2,3-Diphosphoglycerate Decreases in Response to a 30 km Time Trial Under Hypoxia in Cyclists. Front Physiol 2021; 12:670977. [PMID: 34211402 PMCID: PMC8239298 DOI: 10.3389/fphys.2021.670977] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/11/2021] [Indexed: 11/14/2022] Open
Abstract
Red blood cell 2,3-diphosphoglycerate (2,3-DPG) is one of the factors of rightward-shifted oxygen dissociation curves and decrease of Hb-O2 affinity. The reduction of Hb-O2 affinity is beneficial to O2 unloading at the tissue level. In the current literature, there are no studies about the changes in 2,3-DPG level following acute exercise in moderate hypoxia in athletes. For this reason, the aim of this study was to analyze the effect of prolonged intense exercise under normoxic and hypoxic conditions on 2,3-DPG level in cyclists. Fourteen male trained cyclists performed a simulation of a 30 km time trial (TT) in normoxia and normobaric hypoxia (FiO2 = 16.5%, ~2,000 m). During the TT, the following variables were measured: power, blood oxygen saturation (SpO2), and heart rate (HR). Before and immediately after exercise, the blood level of 2,3-DPG and acid–base equilibrium were determined. The results showed that the mean SpO2 during TT in hypoxia was 8% lower than in normoxia. The reduction of SpO2 in hypoxia resulted in a decrease of average power by 9.6% (p < 0.001) and an increase in the 30 km TT completion time by 3.8% (p < 0.01) compared to normoxia. The exercise in hypoxia caused a significant (p < 0.001) decrease in 2,3-DPG level by 17.6%. After exercise in normoxia, a downward trend of 2,3-DPG level was also observed, but this effect was not statistically significant. The analysis also revealed that changes of acid–base balance were significantly larger (p < 0.05) after exercise in hypoxia than in normoxia. In conclusion, intense exercise in hypoxic conditions leads to a decrease in 2,3-DPG concentration, primarily due to exercise-induced acidosis.
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Affiliation(s)
- Kamila Płoszczyca
- Department of Kinesiology, Institute of Sport - National Research Institute, Warsaw, Poland
| | - Miłosz Czuba
- Department of Kinesiology, Institute of Sport - National Research Institute, Warsaw, Poland
| | - Małgorzata Chalimoniuk
- Department of Physical Education and Health in Biala Podlaska, Józef Piłsudski University of Physical Education in Warsaw, Biala Podlaska, Poland
| | - Robert Gajda
- Center for Sports Cardiology, Gajda-Med Medical Center in Pułtusk, Pułtusk, Poland
| | - Marcin Baranowski
- Department of Physiology, Medical University of Bialystok, Bialystok, Poland
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13
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Zhu Y, Warrenfelt CIC, Flannery JC, Lindgren CA. Extracellular Protons Mediate Presynaptic Homeostatic Potentiation at the Mouse Neuromuscular Junction. Neuroscience 2021; 467:188-200. [PMID: 34215419 DOI: 10.1016/j.neuroscience.2021.01.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 01/27/2023]
Abstract
At the vertebrate neuromuscular junction (NMJ), presynaptic homeostatic potentiation (PHP) refers to the upregulation of neurotransmitter release via an increase in quantal content (QC) when the postsynaptic nicotinic acetylcholine receptors (nAChRs) are partially blocked. The mechanism of PHP has not been completely worked out. In particular, the identity of the presumed retrograde signal is still a mystery. We investigated the role of acid-sensing ion channels (ASICs) and extracellular protons in mediating PHP at the mouse NMJ. We found that blocking AISCs using benzamil, psalmotoxin-1 (PcTx1), or mambalgin-3 (Mamb3) prevented PHP. Likewise, extracellular acidification from pH 7.4 to 7.2 triggered a significant, reversable increase in QC and this increase could be prevented by PcTx1. Interestingly, an acidic saline (pH 7.2) also precluded the subsequent induction of PHP. Using immunofluorescence we observed ASIC2a and ASIC1 subunits at the NMJ. Our results indicate that protons and ASIC channels are involved in activating PHP at the mouse NMJ. We speculate that the partial blockade of nAChRs leads to a modest decrease in the pH of the synaptic cleft (∼0.2 pH units) and this activates ASIC channels on the presynaptic nerve terminal.
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Affiliation(s)
- Yiyang Zhu
- Department of Biology, Grinnell College, Grinnell, IA 50112, USA
| | | | - Jill C Flannery
- Department of Biology, Grinnell College, Grinnell, IA 50112, USA
| | - Clark A Lindgren
- Department of Biology, Grinnell College, Grinnell, IA 50112, USA.
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14
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Serra-Payá N, Garnacho-Castaño MV, Sánchez-Nuño S, Albesa-Albiol L, Girabent-Farrés M, Moizé Arcone L, Fernández AP, García-Fresneda A, Castizo-Olier J, Viñals X, Molina-Raya L, Gomis Bataller M. The Relationship between Resistance Exercise Performance and Ventilatory Efficiency after Beetroot Juice Intake in Well-Trained Athletes. Nutrients 2021; 13:nu13041094. [PMID: 33801665 PMCID: PMC8065812 DOI: 10.3390/nu13041094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/17/2021] [Accepted: 03/25/2021] [Indexed: 11/16/2022] Open
Abstract
The assessment of ventilatory efficiency is critical to understanding the matching of ventilation (VE) and perfusion in the lungs during exercise. This study aimed to establish a causal physiological relationship between ventilatory efficiency and resistance exercise performance after beetroot juice (BJ) intake. Eleven well-trained males performed a resistance exercise test after drinking 140 mL of BJ (~12.8 mmol NO3-) or a placebo (PL). Ventilatory efficiency was assessed by the VE•VCO2-1 slope, the oxygen uptake efficiency slope and the partial pressure of end-tidal carbon dioxide (PetCO2). The two experimental conditions were controlled using a randomized, double-blind crossover design. The resistance exercise test involved repeating the same routine twice, which consisted of wall ball shots plus a full squat (FS) with a 3 min rest or without a rest between the two exercises. A higher weight lifted was detected in the FS exercise after BJ intake compared with the PL during the first routine (p = 0.004). BJ improved the VE•VCO2-1 slope and the PetCO2 during the FS exercise in the first routine and at rest (p < 0.05). BJ intake improved the VE•VCO2-1 slope and the PetCO2 coinciding with the resistance exercise performance. The ergogenic effect of BJ could be induced under aerobic conditions at rest.
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Affiliation(s)
- Noemí Serra-Payá
- School of Health Sciences, TecnoCampus Pompeu Fabra University, Ernest Lluch, 32 (Porta Laietana), 08302 Mataró-Barcelona, Spain; (N.S.-P.); (S.S.-N.); (L.A.-A.); (M.G.-F.); (L.M.A.); (A.P.F.); (A.G.-F.); (J.C.-O.); (X.V.); (M.G.B.)
| | - Manuel Vicente Garnacho-Castaño
- School of Health Sciences, TecnoCampus Pompeu Fabra University, Ernest Lluch, 32 (Porta Laietana), 08302 Mataró-Barcelona, Spain; (N.S.-P.); (S.S.-N.); (L.A.-A.); (M.G.-F.); (L.M.A.); (A.P.F.); (A.G.-F.); (J.C.-O.); (X.V.); (M.G.B.)
- Correspondence: ; Tel.: +34-606275392
| | - Sergio Sánchez-Nuño
- School of Health Sciences, TecnoCampus Pompeu Fabra University, Ernest Lluch, 32 (Porta Laietana), 08302 Mataró-Barcelona, Spain; (N.S.-P.); (S.S.-N.); (L.A.-A.); (M.G.-F.); (L.M.A.); (A.P.F.); (A.G.-F.); (J.C.-O.); (X.V.); (M.G.B.)
| | - Lluís Albesa-Albiol
- School of Health Sciences, TecnoCampus Pompeu Fabra University, Ernest Lluch, 32 (Porta Laietana), 08302 Mataró-Barcelona, Spain; (N.S.-P.); (S.S.-N.); (L.A.-A.); (M.G.-F.); (L.M.A.); (A.P.F.); (A.G.-F.); (J.C.-O.); (X.V.); (M.G.B.)
| | - Montserrat Girabent-Farrés
- School of Health Sciences, TecnoCampus Pompeu Fabra University, Ernest Lluch, 32 (Porta Laietana), 08302 Mataró-Barcelona, Spain; (N.S.-P.); (S.S.-N.); (L.A.-A.); (M.G.-F.); (L.M.A.); (A.P.F.); (A.G.-F.); (J.C.-O.); (X.V.); (M.G.B.)
| | - Luciana Moizé Arcone
- School of Health Sciences, TecnoCampus Pompeu Fabra University, Ernest Lluch, 32 (Porta Laietana), 08302 Mataró-Barcelona, Spain; (N.S.-P.); (S.S.-N.); (L.A.-A.); (M.G.-F.); (L.M.A.); (A.P.F.); (A.G.-F.); (J.C.-O.); (X.V.); (M.G.B.)
| | - Alba Pardo Fernández
- School of Health Sciences, TecnoCampus Pompeu Fabra University, Ernest Lluch, 32 (Porta Laietana), 08302 Mataró-Barcelona, Spain; (N.S.-P.); (S.S.-N.); (L.A.-A.); (M.G.-F.); (L.M.A.); (A.P.F.); (A.G.-F.); (J.C.-O.); (X.V.); (M.G.B.)
| | - Adrián García-Fresneda
- School of Health Sciences, TecnoCampus Pompeu Fabra University, Ernest Lluch, 32 (Porta Laietana), 08302 Mataró-Barcelona, Spain; (N.S.-P.); (S.S.-N.); (L.A.-A.); (M.G.-F.); (L.M.A.); (A.P.F.); (A.G.-F.); (J.C.-O.); (X.V.); (M.G.B.)
| | - Jorge Castizo-Olier
- School of Health Sciences, TecnoCampus Pompeu Fabra University, Ernest Lluch, 32 (Porta Laietana), 08302 Mataró-Barcelona, Spain; (N.S.-P.); (S.S.-N.); (L.A.-A.); (M.G.-F.); (L.M.A.); (A.P.F.); (A.G.-F.); (J.C.-O.); (X.V.); (M.G.B.)
| | - Xavier Viñals
- School of Health Sciences, TecnoCampus Pompeu Fabra University, Ernest Lluch, 32 (Porta Laietana), 08302 Mataró-Barcelona, Spain; (N.S.-P.); (S.S.-N.); (L.A.-A.); (M.G.-F.); (L.M.A.); (A.P.F.); (A.G.-F.); (J.C.-O.); (X.V.); (M.G.B.)
| | - Lorena Molina-Raya
- Campus Docent Sant Joan de Déu, Fundación Privada, 08304 Barcelona, Spain;
| | - Manuel Gomis Bataller
- School of Health Sciences, TecnoCampus Pompeu Fabra University, Ernest Lluch, 32 (Porta Laietana), 08302 Mataró-Barcelona, Spain; (N.S.-P.); (S.S.-N.); (L.A.-A.); (M.G.-F.); (L.M.A.); (A.P.F.); (A.G.-F.); (J.C.-O.); (X.V.); (M.G.B.)
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15
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Hackett D. Acute impairment in respiratory muscle strength following a high-volume versus low-volume resistance exercise session. J Sports Med Phys Fitness 2021; 62:395-403. [PMID: 33721982 DOI: 10.23736/s0022-4707.21.12116-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Diminished respiratory muscle has been shown following a strenuous bout of sit-ups however there is a paucity of evidence for this effect following a strenuous upper and lower body resistance training session. This study investigated the acute effect of a highvolume compared to a low-volume resistance exercise session on respiratory muscle strength. METHODS Twenty resistance-trained males (age 25.1 ± 7.4 y) participated in this randomised and cross-over design study. Participants completed two resistance training protocols (highand low-volume) and a control session (no exercise). Sessions involved 5 sets (high-volume) and 2 sets (low-volume) of 10 repetitions at 65% one-repetition maximum for each exercise (bench press, squat, seated shoulder press, and deadlift) with 90 s recovery between sets. Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) was assessed pre-and post-session and respiratory gases were measured during the recovery between sets. RESULTS Following the high-volume session MIP and MEP decreased by a median of 10.0% (interquartile range, IQR = -15.2 to -2.6%) and 12.1% (IQR = -22.2 to -3.9%), respectively, which was significant compared to the low-volume (p<0.001) and control sessions (p≤ 0.001). At 20-min post high-volume session MEP returned to baseline whereas MIP returned to baseline values at 40-min. Greater metabolic stress was associated with the higher-volume session as demonstrated by a lower recovery end-tidal CO2 partial pressure across the majority of exercises (p≤0.008). CONCLUSIONS Findings suggest that respiratory muscle strength is impaired following a highvolume session resistance exercise session, however it appears to be restored within an hour post-exercise.
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Affiliation(s)
- Daniel Hackett
- Exercise, Health and Performance Faculty Research Group, School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Lidcombe, Australia -
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16
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Nam SS, Park HY. Effects of endurance exercise under hypoxia on acid-base and ion balance in healthy males. Phys Act Nutr 2020; 24:7-12. [PMID: 33108712 PMCID: PMC7669468 DOI: 10.20463/pan.2020.0015] [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] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 09/14/2020] [Indexed: 11/22/2022] Open
Abstract
[Purpose] This study was performed to investigate the acid-base and ion balance at rest and after exercise in healthy males under normoxia, moderate hypoxia, and severe hypoxia. [Methods] Ten healthy Korean males completed three different trials on different days, comprising exercise under normoxia (FiO2 = 20.9%, N trial), moderate hypoxia (FiO2 = 16.5%, MH trial), and severe hypoxia (FiO2 = 12.8%, SH trial). They undertook endurance exercise for 30 min on a cycle ergometer at the same relative exercise intensity equivalent to 80% maximal heart rate under all conditions. Capillary blood samples were obtained to determine acid-base and ion balance at rest and after exercise. [Results] Exercise-induced blood lactate elevations were significantly increased as hypoxic conditions became more severe; SH > MH > N trials (P = 0.003). After exercise, blood glucose levels were significantly higher in the SH trial than in the N and MH trials (P = 0.001). Capillary oxygen saturation (SCO2) levels were significantly lowered as hypoxic conditions became more severe; SH > MH > N trials (P < 0.001). The pH levels were significantly lower in the MH trial than that in the N trial (P = 0.010). Moreover, HCO3- levels were significantly lower in the SH trial than in the N trial, with significant interaction (P = 0.003). There were no significant differences in blood Na+, K+, and Ca2+ levels between the trials. [Conclusion] MH and SH trials induced greater differences in glucose, lactate, SCO2, pH, and HCO3- levels in capillary blood compared to the N trial. Additionally, lactate, SCO2, and HCO3- levels showed greater changes in the SH trial than in the MH trial. However, there were no significant differences in Na+, K+, and Ca2+ levels in MH and SH trials compared to the N trial.
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Affiliation(s)
- Sang-Seok Nam
- Taekwondo Research Institute of Kukkiwon, Seoul, Korea
| | - Hun-Young Park
- Department of Sports Medicine and Science of Graduated School, Konkuk University, Seoul, Korea.,Physical Activity and Performance Institute (PAPI), Konkuk University, Seoul, Korea
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17
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Hackett D. Acute effects of high-volume compared to low-volume resistance exercise on lung function. J Exerc Rehabil 2020; 16:450-457. [PMID: 33178647 PMCID: PMC7609852 DOI: 10.12965/jer.2040656.328] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 09/23/2020] [Indexed: 12/19/2022] Open
Abstract
The aim of this study was to examine whether a high-volume compared to low-volume resistance exercise session acutely impairs lung function. Fourteen males (age 23.8±6.5 years) with resistance training experience participated in this study. Participants completed two resistance training protocols (high- and low-volume) and a control session (no exercise) with the sequence randomised. High- and low-volume sessions involved 5 sets (5-SETS) and 2 sets (2-SETS), respectively of 10 repetitions at 65% one-repetition maximum for each exercise (bench press, squat, seated shoulder press, and deadlift) with 90-sec recovery between sets. Lung function was evaulated pre- and postsession and respiratory gases were measured during the recovery between sets of exercises. An increase in the ratio of forced expiratory volume in 1 sec (FEV1) to forced vital capacity was found following the 5-SETS compared to 2-SETS (P=0.033). There was a significant reduction in inspiratory capacity following 5-SETS compared to control session (P=0.049). No other lung function parameter was affected postsession. During training sessions, the squat and deadlift required greater ventilatory demands compared to the bench press and shoulder press (P<0.001). Across most exercises during 5-SETS compared to 2-SETS, there was a lower end-tidal CO2 partial pressure. Across most exercises during 5-SETS compared to 2-SETS there was a lower end-tidal CO2 partial pressure (PETCO2) (P≤0.013), although there were no other differences in physiological responses between the sessions. The findings tend to suggest that the ventilatory and respiratory muscle demands of a strenuous resistance exercise session are not great enough to acutely impair indices of lung function.
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Affiliation(s)
- Daniel Hackett
- Physical Activity, Lifestyle, Ageing and Wellbeing Faculty Research Group, School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
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18
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Limmer M, de Marées M, Platen P. Alterations in acid-base balance and high-intensity exercise performance after short-term and long-term exposure to acute normobaric hypoxic conditions. Sci Rep 2020; 10:13732. [PMID: 32792614 PMCID: PMC7426914 DOI: 10.1038/s41598-020-70762-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 08/04/2020] [Indexed: 11/21/2022] Open
Abstract
This investigation assessed the course of renal compensation of hypoxia-induced respiratory alkalosis by elimination of bicarbonate ions and impairments in anaerobic exercise after different durations of hypoxic exposure. Study A: 16 participants underwent a resting 12-h exposure to normobaric hypoxia (3,000 m). Blood gas analysis was assessed hourly. While blood pH was significantly increased, PO2, PCO2, and SaO2 were decreased within the first hour of hypoxia, and changes remained consistent. A substantial reduction in [HCO3-] levels was observed after 12 h of hypoxic exposure (- 1.35 ± 0.29 mmol/L, p ≤ 0.05). Study B: 24 participants performed in a randomized, cross-over trial portable tethered sprint running (PTSR) tests under normoxia and after either 1 h (n = 12) or 12 h (n = 12) of normobaric hypoxia (3,000 m). No differences occurred for PTSR-related performance parameters, but the reduction in blood lactate levels was greater after 12 h compared with 1 h (- 1.9 ± 2.2 vs 0.0 ± 2.3 mmol/L, p ≤ 0.05). These results indicate uncompensated respiratory alkalosis after 12 h of hypoxia and similar impairment of high-intensity exercise after 1 and 12 h of hypoxic exposure, despite a greater reduction in blood lactate responses after 12 h compared with 1 h of hypoxic exposure.
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Affiliation(s)
- Mirjam Limmer
- Institute of Sports Medicine and Sports Nutrition, Ruhr-University Bochum, Bochum, Germany.
- Institute of Outdoor Sports and Environmental Science, German Sports University Cologne, Cologne, Germany.
| | - Markus de Marées
- Institute of Sports Medicine and Sports Nutrition, Ruhr-University Bochum, Bochum, Germany
| | - Petra Platen
- Institute of Sports Medicine and Sports Nutrition, Ruhr-University Bochum, Bochum, Germany
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19
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Liu C, Shao C, Du Q, He C, Sun X, Lou A, Ma Z, Yu J. Mechanism and effects of fructose diphosphate on anti-hypoxia fatigue and learning memory ability. Can J Physiol Pharmacol 2020; 98:733-740. [PMID: 32551885 DOI: 10.1139/cjpp-2019-0690] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
This study aims to investigate the mechanisms through which fructose diphosphate (FDP) causes anti-hypoxia and anti-fatigue effects and improves learning and memory. Mice were divided into three groups: low-dose FDP (FDP-L), high-dose FDP (FDP-H), and a control group. Acute toxic hypoxia induced by carbon monoxide, sodium nitrite, and potassium cyanide and acute cerebral ischemic hypoxia were used to investigate the anti-hypoxia ability of FDP. The tests of rod-rotating, mouse tail suspension, and swimming endurance were used to explore the anti-fatigue effects of FDP. The Morris water maze experiment was used to determine the impact of FDP on learning and memory ability. Poisoning-induced hypoxic tests showed that mouse survival time was significantly prolonged in the FDP-L and FDP-H groups compared with the control group (p < 0.05). In the exhaustive swimming test, FDP significantly shortened struggling time and prolonged the time of mass-loaded swimming; the rod-rotating test showed that endurance time was significantly prolonged by using FDP (p < 0.05). FDP significantly decreased lactate and urea nitrogen levels and increased hepatic and muscle glycogen and glucose transporter-4 and Na+-K+-ATPase (p < 0.05). To conclude, FDP enhances hypoxia tolerance and fatigue resistance and improves learning and memory ability through regulating glucose and energy metabolism.
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Affiliation(s)
- Chunna Liu
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, People's Republic of China.,Department of Pharmacology, Jinzhou Medical University, Jinzhou 121001, People's Republic of China
| | - Chunhua Shao
- Faculty of Health and Life Sciences, Coach Lane Campus, Northumbria University, Newcastle upon Tyne, NE7 7LN, UK
| | - Qi Du
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, People's Republic of China
| | - Chaoran He
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, People's Republic of China
| | - Xinyuan Sun
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, People's Republic of China
| | - Anqi Lou
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, People's Republic of China
| | - Zhijie Ma
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, People's Republic of China
| | - Junxian Yu
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, People's Republic of China
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20
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Factors Related to Cardiac Troponin T Increase after Participation in a 100 Km Ultra-Marathon. Diagnostics (Basel) 2020; 10:diagnostics10030167. [PMID: 32204320 PMCID: PMC7151175 DOI: 10.3390/diagnostics10030167] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/15/2020] [Accepted: 03/16/2020] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Intensive and prolonged exercise leads to a rise of troponin concentration in blood. The mechanism responsible for troponin release during exercise remains ill-defined. The study aim was to search for risk factors of troponin increase after a prolonged endurance competition. METHODS The study included a group of 18 amateurs, healthy volunteers (median age 41.5 years, interquartile range - IQR 36-53 years, 83% male) who participated in a 100 km running ultra-marathon. Information on demographic characteristics, pre- and post-race heart rate, blood pressure, body composition and glucose, lactate (L), troponin T (hs-TnT) and C reactive protein (hs-CRP) concentration were obtained. Additionally, data on L and glucose levels every 9.2 km and fluid/food intakes during the race were collected. RESULTS There was a significant hs-TnT increase after the race exceeding upper reference values in 66% of runners (from 5 IQR 3-7 ng/L to 14 IQR 12-26 ng/L, p < 0.0001). None of the baseline parameters predicted a post-race hs-TnT increase. The only factors, correlating with changes of hs-TnT were mean L concentration during the race (rho = 0.52, p = 0.03) and change of hs-CRP concentration (rho = 0.59, p = 0.01). CONCLUSIONS Participation in a 100 km ultra-marathon leads to a modest, but significant hs-TnT increase in the majority of runners. Among analysed parameters only mean lactate concentration during the race and change in hs-CRP correlated with troponin change.
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21
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Effects of 2-Week Exercise Training in Hypobaric Hypoxic Conditions on Exercise Performance and Immune Function in Korean National Cycling Athletes with Disabilities: A Case Report. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17030861. [PMID: 32019079 PMCID: PMC7037344 DOI: 10.3390/ijerph17030861] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 01/29/2020] [Accepted: 01/29/2020] [Indexed: 12/18/2022]
Abstract
We aimed to evaluate the effects of a 2-week exercise training program in hypobaric hypoxic conditions on exercise performance and immune function in Korean national cycling athletes with disabilities. Six Korean national cycling athletes with disabilities participated in exercise training consisting of continuous aerobic exercise and anaerobic interval exercise in hypobaric hypoxic conditions. The exercise training frequency was 60 min (5 days per week for 2 weeks). Before and after the exercise training, exercise performance and immune function were measured in all athletes. Regarding the exercise performance parameters, the 3-km time trial significantly decreased and blood lactate levels after the 3-km time trial test significantly increased by exercise training in hypobaric hypoxic conditions. Regarding the oxygen-transporting capacity, significant differences were not observed. Regarding immune function, the number of leukocytes and natural killer cells significantly decreased and that of eosinophils, B cells, and T cells significantly increased. These results indicated that our 2-week hypoxic training showed the potential to improve exercise performance in Korean national disabled athletes. However, the effects of our hypoxic training method on immune function remained unclear.
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Emrich IE, Dederer J, Kircher A, Klemis V, Lennartz CS, Untersteller K, Wagenpfeil S, Fliser D, Wolf M, Heine GH. Does a rise in plasma erythropoietin after high-altitude exposure affect FGF23 in healthy volunteers on a normal or low-phosphorus diet? Nutr Metab Cardiovasc Dis 2019; 29:1361-1367. [PMID: 31653518 DOI: 10.1016/j.numecd.2019.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 08/11/2019] [Accepted: 09/02/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIMS Data of experimental rodent models suggest that hypoxia with subsequent increase in erythropoietin stimulates the expression of the phosphaturic hormone fibroblast growth factor 23 (FGF23). METHODS AND RESULTS To translate the findings of animal studies into human physiology, herein we exposed eight healthy volunteers to high altitude (2656 m above sea level) for four days. The volunteers were randomized on a low-phosphorous diet (n = 4) or a normal phosphorus diet (n = 4). Although high-altitude exposure caused a significant increase in plasma erythropoietin (EPO) (before high-altitude exposure: low phosphorus: median EPO 6.6 mIU/ml [interquartile range (IQR) 6.0; 8.2], normal phosphorus: median EPO 9.0 mIU/ml [IQR 7.9; 11.5]; at day 2: low phosphorus: median EPO 21.3 mIU/ml [IQR 19.5; 23.8], normal phosphorus: median EPO 19.4 mIU/ml [IQR 18.0; 20.8]), there was no consistent increase in plasma c-terminal FGF23 or plasma intact FGF23. We observed only a single, intermittent peak in c-terminal FGF23 levels after 5 h of maximal aerobic exercise. CONCLUSION These data do not support a substantial effect of moderate hypoxia alone on the expression of FGF23, but they suggest that combined exercise and high-altitude exposure may temporarily induce FGF23 expression.
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Affiliation(s)
- Insa E Emrich
- Saarland University Medical Center, Internal Medicine IV - Nephrology and Hypertension, Homburg, Germany.
| | - Juliane Dederer
- Saarland University Medical Center, Internal Medicine III - Cardiology, Angiology and Intensive Care Medicine, Homburg, Germany
| | - Angelika Kircher
- Saarland University Medical Center, Internal Medicine IV - Nephrology and Hypertension, Homburg, Germany
| | - Verena Klemis
- Saarland University, Department of Transplant and Infection Immunology, Homburg, Germany
| | - Claudia S Lennartz
- Saarland University Medical Center, Internal Medicine IV - Nephrology and Hypertension, Homburg, Germany
| | - Kathrin Untersteller
- Saarland University Medical Center, Internal Medicine IV - Nephrology and Hypertension, Homburg, Germany
| | - Stefan Wagenpfeil
- Saarland University Medical Center, Institute for Medical Biometry, Epidemiology and Medical Informatics, Homburg, Germany
| | - Danilo Fliser
- Saarland University Medical Center, Internal Medicine IV - Nephrology and Hypertension, Homburg, Germany
| | - Myles Wolf
- Division of Nephrology, Department of Medicine, Duke University School of Medicine and Duke Clinical Research Institute, Durham, NC, USA
| | - Gunnar H Heine
- Saarland University Medical Center, Internal Medicine IV - Nephrology and Hypertension, Homburg, Germany; Agaplesion Markus Krankenhaus, Frankfurt (Main), Germany
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23
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Gough LA, Deb SK, Brown D, Sparks SA, McNaughton LR. The effects of sodium bicarbonate ingestion on cycling performance and acid base balance recovery in acute normobaric hypoxia. J Sports Sci 2019; 37:1464-1471. [PMID: 30668281 DOI: 10.1080/02640414.2019.1568173] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
This study investigated the effects of two separate doses of sodium bicarbonate (NaHCO3) on 4 km time trial (TT) cycling performance and post-exercise acid base balance recovery in hypoxia. Fourteen club-level cyclists completed four cycling TT's, followed by a 40 min passive recovery in normobaric hypoxic conditions (FiO2 = 14.5%) following one of either: two doses of NaHCO3 (0.2 g.kg-1 BM; SBC2, or 0.3 g.kg-1 BM; SBC3), a taste-matched placebo (0.07 g.kg-1 BM sodium chloride; PLA), or a control trial in a double-blind, randomized, repeated-measures and crossover design study. Compared to PLA, TT performance was improved following SBC2 (p = 0.04, g = 0.16, very likely beneficial), but was improved to a greater extent following SBC3 (p = 0.01, g = 0.24, very likely beneficial). Furthermore, a likely benefit of ingesting SBC3 over SBC2 was observed (p = 0.13, g = 0.10), although there was a large inter-individual variation. Both SBC treatments achieved full recovery within 40 min, which was not observed in either PLA or CON following the TT. In conclusion, NaHCO3 improves 4 km TT performance and acid base balance recovery in acute moderate hypoxic conditions, however the optimal dose warrants an individual approach.
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Affiliation(s)
- Lewis A Gough
- a Sport and Physical Activity Department, Faculty of Health and Life Sciences , Birmingham City University , Birmingham , UK.,b Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK
| | - Sanjoy K Deb
- b Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK.,c Life Sciences Department , University of Westminster , London , UK
| | - Danny Brown
- b Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK
| | - S Andy Sparks
- b Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK
| | - Lars R McNaughton
- b Sports Nutrition and Performance Group, Department of Sport and Physical Activity , Edge Hill University , Ormskirk , UK.,d Department of Sport and Movement Studies, Faculty of Health Science , University of Johannesburg , Johannesburg , South Africa
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24
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박훈영, 임기원, 김지수. Exercise physiology basis and necessity of hypoxic training to improve exercise performance in elite athletes. ACTA ACUST UNITED AC 2018. [DOI: 10.24985/kjss.2018.29.4.737] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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25
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Mourot L. Limitation of Maximal Heart Rate in Hypoxia: Mechanisms and Clinical Importance. Front Physiol 2018; 9:972. [PMID: 30083108 PMCID: PMC6064954 DOI: 10.3389/fphys.2018.00972] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/02/2018] [Indexed: 12/17/2022] Open
Abstract
The use of exercise intervention in hypoxia has grown in popularity amongst patients, with encouraging results compared to similar intervention in normoxia. The prescription of exercise for patients largely rely on heart rate recordings (percentage of maximal heart rate (HRmax) or heart rate reserve). It is known that HRmax decreases with high altitude and the duration of the stay (acclimatization). At an altitude typically chosen for training (2,000-3,500 m) conflicting results have been found. Whether or not this decrease exists or not is of importance since the results of previous studies assessing hypoxic training based on HR may be biased due to improper intensity. By pooling the results of 86 studies, this literature review emphasizes that HRmax decreases progressively with increasing hypoxia. The dose–response is roughly linear and starts at a low altitude, but with large inter-study variabilities. Sex or age does not seem to be a major contributor in the HRmax decline with altitude. Rather, it seems that the greater the reduction in arterial oxygen saturation, the greater the reduction in HRmax, due to an over activity of the parasympathetic nervous system. Only a few studies reported HRmax at sea/low level and altitude with patients. Altogether, due to very different experimental design, it is difficult to draw firm conclusions in these different clinical categories of people. Hence, forthcoming studies in specific groups of patients are required to properly evaluate (1) the HRmax change during acute hypoxia and the contributing factors, and (2) the physiological and clinical effects of exercise training in hypoxia with adequate prescription of exercise training intensity if based on heart rate.
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Affiliation(s)
- Laurent Mourot
- EA 3920 Prognostic Markers and Regulatory Factors of Cardiovascular Diseases and Exercise Performance, Health, Innovation Platform, University of Franche-Comté, Besançon, France.,Tomsk Polytechnic University, Tomsk, Russia
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26
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Böning D, Maassen N. Relation between lactic acid and base excess during muscular exercise. Eur J Appl Physiol 2018; 118:863-864. [PMID: 29450628 DOI: 10.1007/s00421-018-3824-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 02/10/2018] [Indexed: 10/18/2022]
Affiliation(s)
- Dieter Böning
- Institut für Physiologie, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
| | - Norbert Maassen
- Institut für Sportmedizin, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625, Hanover, Germany
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27
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Lühker O, Pohlmann A, Hochreiter M, Berger MM. Acid-base balance during muscular exercise: response to Dr. Böning and Dr. Maassen. Eur J Appl Physiol 2018; 118:865-866. [PMID: 29470641 DOI: 10.1007/s00421-018-3825-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 02/10/2018] [Indexed: 11/25/2022]
Affiliation(s)
- Olaf Lühker
- Department of Anesthesiology, University Medical Centre Groningen, Groningen, The Netherlands
- Department of Anesthesiology, University Hospital Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany
| | - Alexander Pohlmann
- Department of Anesthesiology, University Hospital Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany
| | - Marcel Hochreiter
- Department of Anesthesiology, University Hospital Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany.
| | - Marc Moritz Berger
- Department of Anesthesiology, University Hospital Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
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