Excess VO 2 during ramp exercise is positively correlated to intercostal muscles deoxyhemoglobin levels above the gas exchange threshold in young trained cyclists

2016 ◽  
Vol 228 ◽  
pp. 83-90 ◽  
Author(s):  
Ferid Oueslati ◽  
Olivier Girard ◽  
Zouhair Tabka ◽  
Said Ahmaidi
Keyword(s):  
Gas Exchange ◽  
Intercostal Muscles ◽  
Ramp Exercise ◽  
Gas Exchange Threshold

Gas Exchange Threshold in Male Speed–Power versus Endurance Athletes Ages 20–90 Years

2012 ◽  
Vol 44 (12) ◽  
pp. 2415-2422 ◽  
Author(s):  
KRZYSZTOF KUSY ◽  
MAGDALENA KRÓL-ZIELIŃSKA ◽  
KATARZYNA DOMASZEWSKA ◽  
JAKUB KRYŚCIAK ◽  
TOMASZ PODGÓRSKI ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Endurance Athletes ◽  
Gas Exchange Threshold

scholarly journals A Rapidly-Incremented Tethered-Swimming Test for Defining Domain-Specific Training Zones

2017 ◽  
Vol 57 (1) ◽  
pp. 117-128
Author(s):  
Dalton M. Pessôa Filho ◽  
Leandro O.C. Siqueira ◽  
Astor R. Simionato ◽  
Mário A.C. Espada ◽  
Daniel S. Pestana ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Work Rate ◽  
Metabolic Rates ◽  
Incremental Test ◽  
Domain Specific ◽  
Respiratory Compensation ◽  
Exercise Economy ◽  
Constant Work Rate ◽  
Swimming Test ◽  
Gas Exchange Threshold

AbstractThe purpose of this study was to investigate whether a tethered-swimming incremental test comprising small increases in resistive force applied every 60 seconds could delineate the isocapnic region during rapidly-incremented exercise. Sixteen competitive swimmers (male, n = 11; female, n = 5) performed: (a) a test to determine highest force during 30 seconds of all-out tethered swimming (Favg) and the ΔF, which represented the difference between Favg and the force required to maintain body alignment (Fbase), and (b) an incremental test beginning with 60 seconds of tethered swimming against a load that exceeded Fbase by 30% of ΔF followed by increments of 5% of ΔF every 60 seconds. This incremental test was continued until the limit of tolerance with pulmonary gas exchange (rates of oxygen uptake and carbon dioxide production) and ventilatory (rate of minute ventilation) data collected breath by breath. These data were subsequently analyzed to determine whether two breakpoints defining the isocapnic region (i.e., gas exchange threshold and respiratory compensation point) were present. We also determined the peak rate of O2 uptake and exercise economy during the incremental test. The gas exchange threshold and respiratory compensation point were observed for each test such that the associated metabolic rates, which bound the heavy-intensity domain during constant-work-rate exercise, could be determined. Significant correlations (Spearman’s) were observed for exercise economy along with (a) peak rate of oxygen uptake (ρ = .562; p < 0.025), and (b) metabolic rate at gas exchange threshold (ρ = −.759; p < 0.005). A rapidly-incremented tethered-swimming test allows for determination of the metabolic rates that define zones for domain-specific constant-work-rate training.

Gas Exchange Threshold and V[Combining Dot Above]O2max Testing for Athletes

2013 ◽  
Vol 27 (2) ◽  
pp. 549-555 ◽  
Author(s):  
Robert W. Pettitt ◽  
Ida E. Clark ◽  
Stacy M. Ebner ◽  
Daniel T. Sedgeman ◽  
Steven R. Murray
Keyword(s):  
Gas Exchange ◽  
Gas Exchange Threshold

Airways and alveoli

2020 ◽  
pp. 3937-3946
Author(s):  
Peter D. Wagner ◽  
Pallav L. Shah
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Structure Function ◽  
Lung Diseases ◽  
Passive Diffusion ◽  
Thoracic Cavity ◽  
Intercostal Muscles ◽  
Clinical Consequences

The lung is the organ of gas exchange, providing the means of transferring oxygen (O2) from the air to the blood by passive diffusion for subsequent distribution to the tissues, and of similarly removing metabolically produced carbon dioxide (CO2) from the blood, which is then exhaled to the atmosphere. The lungs are enclosed within the thoracic cavity. Inspiration is driven by contraction of the intercostal muscles and the diaphragm, which expands the ribcage in both anteroposterior and lateral dimensions, such that the pressure inside the thoracic cavity but external to the lungs is reduced to below that of the air, which is thereby drawn in. Lung diseases of many types commonly affect each of the steps involved in gas exchange, and the clinical consequences can usually be readily understood if the structure–function relationships are known.

Mechanistic basis for the gas exchange threshold in Thoroughbred horses

2002 ◽  
Vol 92 (4) ◽  
pp. 1499-1505 ◽  
Author(s):  
Paul McDonough ◽  
Casey A. Kindig ◽  
Howard H. Erickson ◽  
David C. Poole
Keyword(s):  
Gas Exchange ◽  
Ventilatory Threshold ◽  
Healthy Humans ◽  
Thoroughbred Horses ◽  
Ventilatory Equivalent ◽  
Mechanistic Basis ◽  
Cardiopulmonary Performance ◽  
The Relationship ◽  
Peak Blood ◽  
Gas Exchange Threshold

The exercising Thoroughbred horse (TB) is capable of exceptional cardiopulmonary performance. However, because the ventilatory equivalent for O2(V˙e/V˙o 2) does not increase above the gas exchange threshold (Tge), hypercapnia and hypoxemia accompany intense exercise in the TB compared with humans, in whom V˙e/V˙o 2 increases during supra-Tge work, which both removes the CO2 produced by the HCO[Formula: see text] buffering of lactic acid and prevents arterial partial pressure of CO2 (PaCO2 ) from rising. We used breath-by-breath techniques to analyze the relationship between CO2 output (V˙co 2) andV˙o 2 [V-slope lactate threshold (LT) estimation] during an incremental test to fatigue (7 to ∼15 m/s; 1 m · s−1 · min−1) in six TB. Peak blood lactate increased to 29.2 ± 1.9 mM/l. However, as neither V˙e/V˙o 2 norV˙e/V˙co 2 increased, PaCO2 increased to 56.6 ± 2.3 Torr at peakV˙o 2(V˙o 2 max). Despite the presence of a relative hypoventilation (i.e., no increase inV˙e/V˙o 2 orV˙e/V˙co 2), a distinct Tge was evidenced at 62.6 ± 2.7%V˙o 2 max. Tge occurred at a significantly higher ( P < 0.05) percentage ofV˙o 2 max than the lactate (45.1 ± 5.0%) or pH (47.4 ± 6.6%) but not the bicarbonate (65.3 ± 6.6%) threshold. In addition, PaCO2 was elevated significantly only at a workload > Tge. Thus, in marked contrast to healthy humans, pronounced V-slope (↑V˙co 2/V˙o 2) behavior occurs in TB concomitant with elevated PaCO2 and without evidence of a ventilatory threshold.

scholarly journals Exercise Testing of Adolescents and Young Adults With Sickle Cell Disease: Perceptual Responses and the Gas Exchange Threshold

2019 ◽  
Vol 36 (5) ◽  
pp. 310-320
Author(s):  
Suzanne Ameringer ◽  
R. K. Elswick ◽  
India Sisler ◽  
Wally Smith ◽  
Thokozeni Lipato ◽  
...  
Keyword(s):  
Young Adults ◽  
Sickle Cell Disease ◽  
Gas Exchange ◽  
Sickle Cell ◽  
Self Regulation ◽  
Adolescents And Young Adults ◽  
Published Data ◽  
Cell Disease ◽  
Perceived Effort ◽  
Gas Exchange Threshold

For individuals with sickle cell disease (SCD), mild to moderate exercise is advised, but self-regulation of these intensities is difficult. To regulate intensity, one SCD recommendation is to stop exercising at the first perception of fatigue. However, perceived effort and affect (how one feels) are perceptual cues that are commonly used to guide exercise intensity. This study (a) examined perceived effort, affect, and fatigue in relation to metabolic state (gas exchange) in adolescents and young adults (AYAs) with SCD, (b) explored guidelines AYAs use to self-regulate exercise, and (c) compared perceived effort and affect at gas exchange threshold (GET) with healthy counterparts. Twenty-two AYAs with SCD completed an incremental cycle test. Perceived effort, affect, and fatigue were assessed every 2 minutes. A mixed-effects linear model was conducted to model changes in effort, affect, and fatigue across time. Mean scores of effort and affect at GET were compared with published data of healthy counterparts. Participants were queried about self-regulation exercise strategies. Findings indicated that both perceived fatigue and effort at GET was lower than expected. Perceived effort was lower ( p < .0001), and perceived affect was significantly higher ( p = .0009) than healthy counterparts. Interviews revealed that most participants (95%) do not stop exercising until fatigue is moderate to severe, and many (73%) do not stop until symptoms are severe (chest tightness, blurry vision). Nurses should review guidelines for safe exercise with AYAs with SCD. Exercise training may be beneficial to AYAs with SCD for learning how to interpret bodily responses to exercise to improve self-regulation.

Use of the Gas Exchange Threshold to Noninvasively Determine the Lactate Threshold in Patients With Cystic Fibrosis

CHEST Journal ◽  
2002 ◽  
Vol 121 (6) ◽  
pp. 1761-1770 ◽  
Author(s):  
Alasdair G. Thin ◽  
Seamus J. Linnane ◽  
Edward F. McKone ◽  
Rosemarie Freaney ◽  
Muiris X. FitzGerald ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Gas Exchange ◽  
Lactate Threshold ◽  
Gas Exchange Threshold

scholarly journals Muscle metabolic and neuromuscular determinants of fatigue during cycling in different exercise intensity domains

2017 ◽  
Vol 122 (3) ◽  
pp. 446-459 ◽  
Author(s):  
Matthew I. Black ◽  
Andrew M. Jones ◽  
Jamie R. Blackwell ◽  
Stephen J. Bailey ◽  
Lee J. Wylie ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Exercise Intensity ◽  
Wave Amplitude ◽  
Critical Power ◽  
Moderate Intensity ◽  
Neural Drive ◽  
M Wave ◽  
Fatigue Development ◽  
Neuromuscular Responses ◽  
Gas Exchange Threshold

Lactate or gas exchange threshold (GET) and critical power (CP) are closely associated with human exercise performance. We tested the hypothesis that the limit of tolerance (Tlim) during cycle exercise performed within the exercise intensity domains demarcated by GET and CP is linked to discrete muscle metabolic and neuromuscular responses. Eleven men performed a ramp incremental exercise test, 4–5 severe-intensity (SEV; >CP) constant-work-rate (CWR) tests until Tlim, a heavy-intensity (HVY; <CP but >GET) CWR test until Tlim, and a moderate-intensity (MOD; <GET) CWR test until Tlim. Muscle biopsies revealed that a similar ( P > 0.05) muscle metabolic milieu (i.e., low pH and [PCr] and high [lactate]) was attained at Tlim (approximately 2–14 min) for all SEV exercise bouts. The muscle metabolic perturbation was greater at Tlim following SEV compared with HVY, and also following SEV and HVY compared with MOD (all P < 0.05). The normalized M-wave amplitude for the vastus lateralis (VL) muscle decreased to a similar extent following SEV (−38 ± 15%), HVY (−68 ± 24%), and MOD (−53 ± 29%), ( P > 0.05). Neural drive to the VL increased during SEV (4 ± 4%; P < 0.05) but did not change during HVY or MOD ( P > 0.05). During SEV and HVY, but not MOD, the rates of change in M-wave amplitude and neural drive were correlated with changes in muscle metabolic ([PCr], [lactate]) and blood ionic/acid-base status ([lactate], [K+]) ( P < 0.05). The results of this study indicate that the metabolic and neuromuscular determinants of fatigue development differ according to the intensity domain in which the exercise is performed. NEW & NOTEWORTHY The gas exchange threshold and the critical power demarcate discrete exercise intensity domains. For the first time, we show that the limit of tolerance during whole-body exercise within these domains is characterized by distinct metabolic and neuromuscular responses. Fatigue development during exercise greater than critical power is associated with the attainment of consistent “limiting” values of muscle metabolites, whereas substrate availability and limitations to muscle activation may constrain performance at lower intensities.

scholarly journals Constant Load Exercise at Gas Exchange Threshold is Accompanied by a Distinct Elevation in Blood Lactate Level

2020 ◽  
Author(s):  
kazuyuki kominami ◽  
Hirotaka Nishijima ◽  
Keiko Imahashi ◽  
Toko Katsuragawa ◽  
Mitsuyo Murakami ◽  
...  
Keyword(s):  
Steady State ◽  
Gas Exchange ◽  
Blood Lactate ◽  
Perceived Exertion ◽  
State Level ◽  
The Elderly ◽  
Constant Load ◽  
Healthy Elderly ◽  
Gas Exchange Threshold ◽  
Constant Load Exercise

Abstract Background: The gas exchange threshold (GET) is determined during incremental exercise (Inc-Ex) testing. It is generally considered to be a safe training intensity, with little or no elevation in blood lactate (BLa). However, actual exercise training at GET is carried out primarily as a constant load exercise (CL-Ex). The dynamics of BLa during CL-Ex at GET have not been studied. This study was conducted particularly among the elderly population. Methods: We recruited 20 healthy elderly individuals (H: age 69.4±6.8 years) and 10 patients with cardiovascular diseases or under medication for cardiovascular risk factors (P: age 73.0±8.8 years). On day 1, we determined GET during symptomatic maximal Inc-Ex. On day 2, CL-Ex at GET intensity was performed for 20 min. Arterialized blood lactate levels were determined. Results: The mean BLa at GET during Inc-Ex was 1.51±0.29 mmol/L in H and 1.78±0.42 mmol/L in P (p < 0.05). During CL-Ex, BLa increased significantly more than that at GET, reaching a steady state level of 2.65±1.56 (H) and 2.53±0.95 (P) mmol/L (ns), with a mean respiratory exchange ratio (RER) of 0.94±0.05 (H) and 0.93±0.05 (P) (ns). Oxygen uptake (VO2) also reached a steady state in all participants. All participants were able to complete CL-Ex with mean perceived exertion ratings (Borg/20) of 11.8±1.3 (H) and 12.2±1.3 (P) (ns). Conclusions: CL-Ex at GET occurred at distinctly increased BLa levels; however, BLa reached a steady state, together with VO2 and RER, indicating that exercise intensity was metabolically moderate.

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