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.

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

Exercise intensity and markers of inflammation during and after (neo-) adjuvant cancer treatment

2021 ◽  
Vol 28 (3) ◽  
pp. 191-201
Author(s):  
Tim Schauer ◽  
Anne-Sophie Mazzoni ◽  
Anna Henriksson ◽  
Ingrid Demmelmaier ◽  
Sveinung Berntsen ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Treatment ◽  
Exercise Intensity ◽  
Interleukin 1 ◽  
Secondary Analysis ◽  
Post Treatment ◽  
Moderate Intensity ◽  
Post Intervention ◽  
Necrosis Factor Alpha ◽  
Markers Of Inflammation

Exercise training has been hypothesized to lower the inflammatory burden for patients with cancer, but the role of exercise intensity is unknown. To this end, we compared the effects of high-intensity (HI) and low-to-moderate intensity (LMI) exercise on markers of inflammation in patients with curable breast, prostate and colorectal cancer undergoing primary adjuvant cancer treatment in a secondary analysis of the Phys-Can randomized trial (NCT02473003). Sub-group analyses focused on patients with breast cancer undergoing chemotherapy. Patients performed 6 months of combined aerobic and resistance exercise on either HI or LMI during and after primary adjuvant cancer treatment. Plasma taken at baseline, immediately post-treatment and post-intervention was analyzed for levels of interleukin 1 beta (IL1B), IL6, IL8, IL10, tumor-necrosis factor alpha (TNFA) and C-reactive protein (CRP). Intention-to-treat analyses of 394 participants revealed no significant between-group differences. Regardless of exercise intensity, significant increases of IL6, IL8, IL10 and TNFA post-treatment followed by significant declines, except for IL8, until post-intervention were observed with no difference for CRP or IL1B. Subgroup analyses of 154 patients with breast cancer undergoing chemotherapy revealed that CRP (estimated mean difference (95% CI): 0.59 (0.33; 1.06); P  = 0.101) and TNFA (EMD (95% CI): 0.88 (0.77; 1); P  = 0.053) increased less with HI exercise post-treatment compared to LMI. Exploratory cytokine co-regulation analysis revealed no difference between the groups. In patients with breast cancer undergoing chemotherapy, HI exercise resulted in a lesser increase of CRP and TNFA immediately post-treatment compared to LMI, potentially protecting against chemotherapy-related inflammation.

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.

scholarly journals Objective and subjective measures of exercise intensity during thermo-neutral and hot yoga

2018 ◽  
Vol 43 (4) ◽  
pp. 397-402 ◽  
Author(s):  
Corinne N. Boyd ◽  
Stephanie M. Lannan ◽  
Micah N. Zuhl ◽  
Ricardo Mora-Rodriguez ◽  
Rachael K. Nelson
Keyword(s):  
Oxygen Consumption ◽  
Light Intensity ◽  
Exercise Intensity ◽  
Perceived Exertion ◽  
Maximal Oxygen Consumption ◽  
Rating Of Perceived Exertion ◽  
Moderate Intensity ◽  
Subjective Measures ◽  
Moderate Intensity Exercise ◽  
Constant Intensity

While hot yoga has gained enormous popularity in recent years, owing in part to increased environmental challenge associated with exercise in the heat, it is not clear whether hot yoga is more vigorous than thermo-neutral yoga. Therefore, the aim of this study was to determine objective and subjective measures of exercise intensity during constant intensity yoga in a hot and thermo-neutral environment. Using a randomized, crossover design, 14 participants completed 2 identical ∼20-min yoga sessions in a hot (35.3 ± 0.8 °C; humidity: 20.5% ± 1.4%) and thermo-neutral (22.1 ± 0.2 °C; humidity: 27.8% ± 1.6%) environment. Oxygen consumption and heart rate (HR) were recorded as objective measures (percentage of maximal oxygen consumption and percentage of maximal HR (%HRmax)) and rating of perceived exertion (RPE) was recorded as a subjective measure of exercise intensity. There was no difference in exercise intensity based on percentage of maximal oxygen consumption during hot versus thermo-neutral yoga (30.9% ± 2.3% vs. 30.5% ± 1.8%, p = 0.68). However, exercise intensity was significantly higher during hot versus thermo-neutral yoga based on %HRmax (67.0% ± 2.3% vs. 60.8% ± 1.9%, p = 0.01) and RPE (12 ± 1 vs. 11 ± 1, p = 0.04). According to established exercise intensities, hot yoga was classified as light-intensity exercise based on percentage of maximal oxygen consumption but moderate-intensity exercise based on %HRmax and RPE while thermo-neutral yoga was classified as light-intensity exercise based on percentage of maximal oxygen uptake, %HRmax, and RPE. Despite the added hemodynamic stress and perception that yoga is more strenuous in a hot environment, we observed similar oxygen consumption during hot versus thermo-neutral yoga, classifying both exercise modalities as light-intensity exercise.

scholarly journals Validity of Reporting Oxygen Uptake Efficiency Slope from Submaximal Exercise Using Respiratory Exchange Ratio as Secondary Criterion

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Wilby Williamson ◽  
Jonathan Fuld ◽  
Kate Westgate ◽  
Karl Sylvester ◽  
Ulf Ekelund ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Test Data ◽  
Exercise Intensity ◽  
Respiratory Exchange Ratio ◽  
Fold Increase ◽  
Moderate Intensity ◽  
Uptake Efficiency ◽  
Highly Correlated ◽  
Oxygen Uptake Efficiency Slope ◽  
Treadmill Protocol

Background. Oxygen uptake efficiency slope (OUES) is a reproducible, objective marker of cardiopulmonary function. OUES is reported as being relatively independent of exercise intensity. Practical guidance and criteria for reporting OUES from submaximal tests has not been established.Objective. Evaluate the use of respiratory exchange ratio (RER) as a secondary criterion for reporting OUES.Design. 100 healthy volunteers (53 women) completed a ramped treadmill protocol to exhaustive exercise. OUES was calculated from data truncated to RER levels from 0.85 to 1.2 and compared to values generated from full test data. Results. Mean (sd) OUES from full test data and data truncated to RER 1.0 and RER 0.9 was 2814 (718), 2895 (730), and 2810 (789) mL/min per 10-fold increase in VE, respectively. Full test OUES was highly correlated with OUES from RER 1.0 (r=0.9) and moderately correlated with OUES from RER 0.9 (r=0.79).Conclusion. OUES values peaked in association with an RER level of 1.0. Sub-maximal OUES values are not independent of exercise intensity. There is a significant increase in OUES value as exercise moves from low to moderate intensity. RER can be used as a secondary criterion to define this transition.

scholarly journals Physiological Effects of Exercising at Different Intensities Wearing TNT or Double-layer Cotton Facemasks Compared to Not Wearing a Mask

2020 ◽  
Author(s):  
Fabrício Braga ◽  
Gabriel Espinosa ◽  
Amanda Monteiro ◽  
Beatriz Marinho ◽  
Eduardo Drummond
Keyword(s):  
Gas Exchange ◽  
Double Layer ◽  
Breathing Pattern ◽  
Pulmonary Ventilation ◽  
Effect Sizes ◽  
Moderate Intensity ◽  
List Type ◽  
Physiological Effects ◽  
Physiological Dead Space ◽  
End Tidal

Abstract We compared the physiological differences between exercising wearing a TNT or a double-layer-cotton (DLC) facemask (FM) and not wearing a mask (NM). Sixteen volunteers underwent 4 sets (S) of 2 sequential bouts (B). B1 and B2 corresponded to light and moderate intensity cycling, respectively. FMs were used as follows: S1: NM; S2: TNT or DLC; S3: DLC or TNT; and S4: NM. Metabolic, pulmonary, and perceptual variables were collected. The main results are expressed as effect sizes and confidence intervals (ES [95%CI]) for TNT and DLC unless otherwise indicated. Compared to NM, FM increased the duty cycle (B1=1.11[0.58-1.61] and 1.53[0.81-2.18]; B2=1.27[0.63-1.84] and 1.93[0.97-2.68]) and decreased breath frequency (B1=0.59[0.23-0.94] and 1.43[0.79-2.07], B2=0.39[0.05-0.71] and 1.33[0.71-1.94]). Only B1 tidal volume increased (0.33[0.09-0.56] and 0.62[0.18-1.05]) enough to avoid a ventilation reduction with TNT but not with DLC (B1=0.52[0.23-0.79]; B2=0.84[0.44-1.22]). Both FMs reduced oxygen saturation in B1 (0.56 [0.07-1.03] and 0.69 [0.09-1.28]) but only DLC did so in B2 (0.66 [0.11-1.13]). Both end tidal CO2 (B1=0.23[0.05-0.4] and 0.71[0.38-1.02]; B2=0.56[0.2-0.9] and 1.20[0.65-1.68]) and mixed-expired-CO2 (B1=0.74[0.38-1.08] 1.71[1.03-2.37], B2=0.94[0.45-1.38] and 1.78[0.97-2.42]) increased with FMs. Ventilatory adaptations imposed during FM exercising influenced blood-lung gas exchange. Larger ESs were seen with DLC. No adverse changes to human health were observed. Novelty Bullets Facemasks affect the breathing pattern by changing the frequency and amplitude of pulmonary ventilation. The augmented ventilatory work increases VO2, VCO2, and RPE and promotes non-concerning drops in SpO2 and CO2 retention. Increased inspiratory and expiratory pressure can account for the reduction in pulmonary physiological dead space.

scholarly journals The acute effects of resistance training on fatigue in patients with pulmonary sarcoidosis

2019 ◽  
Author(s):  
Anita Grongstad ◽  
Nina Køpke Vøllestad ◽  
Line Merethe Oldervoll ◽  
Martijn A Spruit ◽  
Anne Edvardsen
Keyword(s):  
Resistance Training ◽  
High Intensity ◽  
Pulmonary Sarcoidosis ◽  
Moderate Intensity ◽  
Exercise Session ◽  
Long Term Effects ◽  
Single Session ◽  
Skeletal Muscle Dysfunction ◽  
Fatigue Development ◽  
Acute Increase

Abstract Introduction: Sarcoidosis-related fatigue and skeletal muscle dysfunction are frequent symptoms in patients with sarcoidosis. Despite lacking knowledge whether high-intensity resistance training (RT) will worsen fatigue, low to moderate intensity is commonly recommended. This study aimed to investigate whether a single session of high-intensity RT will induce a larger acute increase in fatigue than a single RT session of moderate-intensity. Methods: In this crossover study, 41 patients with pulmonary sarcoidosis (age: 53 ± 11 yr) were recruited. They randomly performed one session of high-intensity, 4 sets x 5 repetitions maximum (5RM), and one session of moderate-intensity, 2 sets x 25 RM. Fatigue was assessed with the Visual Analogue Scale (0-100 mm) before (T0), immediately after (T1) and 24 hours after (T2) each exercise session. Results: Fatigue development from T0 to T1 was significantly lower after 5RM (– 3 ± 18 mm) than after 25RM (5 ± 15 mm), p = 0.004. No difference was seen from T0 to T2 between 5RM (0 ± 17 mm) and 25RM (6 ± 18 mm), p = 0.147. Conclusion: Since the 5RM session did not induce a larger increase in fatigue than the 25RM session, a single session of RT thus appears feasible and safe in patients with pulmonary sarcoidosis irrespective of the RT intensity. The long-term effects of high-intensity RT on fatigue should be explored in a RT program of longer duration.

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
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