O2 Uptake in hyperthyroidism during constant work rate and incremental exercise

1991 ◽  
Vol 62 (4) ◽  
pp. 261-267 ◽  
Author(s):  
I. Ben-Dov ◽  
K. E. Sietsema ◽  
K. Wasserman
Keyword(s):  
Work Rate ◽  
Incremental Exercise ◽  
O2 Uptake ◽  
Constant Work Rate

scholarly journals Establishing the V̇o2 versus constant-work-rate relationship from ramp-incremental exercise: simple strategies for an unsolved problem

2019 ◽  
Vol 127 (6) ◽  
pp. 1519-1527 ◽  
Author(s):  
Danilo Iannetta ◽  
Rafael de Almeida Azevedo ◽  
Daniel A. Keir ◽  
Juan M. Murias
Keyword(s):  
Lactate Threshold ◽  
Unsolved Problem ◽  
Critical Power ◽  
Work Rate ◽  
Incremental Exercise ◽  
Mean Response Time ◽  
Constant Work Rate ◽  
Ramp Exercise ◽  
The Mean ◽  
Highly Correlated

The dissociation between constant work rate of O2 uptake (V̇o2) and ramp V̇o2 at a given work rate might be mitigated during slowly increasing ramp protocols. This study characterized the V̇o2 dynamics in response to five different ramp protocols and constant-work-rate trials at the maximal metabolic steady state (MMSS) to characterize 1) the V̇o2 gain (G) in the moderate, heavy, and severe domains, 2) the mean response time of V̇o2 (MRT), and 3) the work rates at lactate threshold (LT) and respiratory compensation point (RCP). Eleven young individuals performed five ramp tests (5, 10, 15, 25, and 30 W/min), four to five time-to-exhaustions for critical power estimation, and two to three constant-work-rate trials for confirmation of the work rate at MMSS. G was greatest during the slowest ramp and progressively decreased with increasing ramp slopes (from ~12 to ~8 ml·min−1·W−1, P < 0.05). The MRT was smallest during the slowest ramp slopes and progressively increased with faster ramp slopes (1 ± 1, 2 ± 1, 5 ± 3, and 10 ± 4, 15 ± 6 W, P < 0.05). After “left shifting” the ramp V̇o2 by the MRT, the work rate at LT was constant regardless of the ramp slope (~150 W, P > 0.05). The work rate at MMSS was 215 ± 55 W and was similar and highly correlated with the work rate at RCP during the 5 W/min ramp ( P > 0.05, r = 0.99; Lin’s concordance coefficient = 0.99; bias = −3 W; root mean square error = 6 W). Findings showed that the dynamics of V̇o2 (i.e., G) during ramp exercise explain the apparent dichotomy existing with constant-work-rate exercise. When these dynamics are appropriately “resolved”, LT is constant regardless of the ramp slope of choice, and RCP and MMSS display minimal variations between each other. NEW & NOTEWORTHY This study demonstrates that the dynamics of V̇o2 during ramp-incremental exercise are dependent on the characteristics of the increments in work rate, such that during slow-incrementing ramp protocols the magnitude of the dissociation between ramp V̇o2 and constant V̇o2 at a given work rate is reduced. Accurately accounting for these dynamics ensures correct characterizations of the V̇o2 kinetics at ramp onset and allows appropriate comparisons between ramp and constant-work-rate exercise-derived indexes of exercise intensity.

Differential ventilatory control during constant work rate and incremental exercise

1994 ◽  
Vol 97 (2) ◽  
pp. 175-187 ◽  
Author(s):  
N.C. Syabbalo ◽  
B. Krishnan ◽  
T. Zintel ◽  
C.G. Gallagher
Keyword(s):  
Work Rate ◽  
Incremental Exercise ◽  
Ventilatory Control ◽  
Constant Work Rate

scholarly journals The constant work rate critical power protocol overestimates ramp incremental exercise performance

2016 ◽  
Vol 116 (11-12) ◽  
pp. 2415-2422 ◽  
Author(s):  
Matthew I. Black ◽  
Andrew M. Jones ◽  
James A. Kelly ◽  
Stephen J. Bailey ◽  
Anni Vanhatalo
Keyword(s):  
Exercise Performance ◽  
Critical Power ◽  
Work Rate ◽  
Incremental Exercise ◽  
Constant Work Rate

scholarly journals Effect of normobaric hypoxic exercise on blood pressure in old individuals

2020 ◽  
Author(s):  
Markus Hein ◽  
Kristine Chobanyan-Jürgens ◽  
Uwe Tegtbur ◽  
Stefan Engeli ◽  
Jens Jordan ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Endurance Training ◽  
Perceived Exertion ◽  
Work Rate ◽  
Incremental Exercise ◽  
Exercise Tests ◽  
Exercise Blood Pressure ◽  
Constant Work Rate ◽  
Registration Number ◽  
Rate Test

Abstract Purpose To test the hypothesis that the combination of endurance training and hypoxia leads to greater improvements in resting and exercise blood pressure in old sedentary individuals compared to endurance training only. Methods We randomly assigned 29 old overweight participants (age: 62 ± 6 years, body mass index (BMI): 28.5 ± 0.5 kg/m2, 52% men) to single blind 8-week bicycle exercise in hypoxia (fraction of inspired oxygen (FIO2) = 0.15) or normoxia (FIO2 = 0.21). Brachial blood pressure was measured at rest, during maximal incremental exercise testing, and during a 30 min constant work rate test, at baseline and after the training period. Results Work rate, heart rate and perceived exertion during training were similar in both groups, with lower oxygen saturation for participants exercising under hypoxia (88.7 ± 1.5 vs. 96.2 ± 1.2%, t(27) = − 13.04, p < 0.001, |g|= 4.85). Office blood pressure and blood pressure during incremental exercise tests did not change significantly in either group after the training program. Systolic blood pressure during the constant work rate test was reduced after training in hypoxia (160 ± 18 vs. 151 ± 14 mmHg, t(13) = 2.44 p < 0.05, |d|= 0.55) but not normoxia (154 ± 22 vs. 150 ± 16 mmHg, t(14) = 0.75, p = 0.46, |d|= 0.18) with no difference between groups over time (F = 0.08, p = 0.77, η2 = 0.01). Conclusion In old individuals hypoxia in addition to exercise does not have superior effects on office or exercise blood pressure compared to training in normoxia. Trial registration number ClinicalTrials.gov No. NCT02196623 (registered 22 July 2014).

Quantitation of progressive muscle fatigue during dynamic leg exercise in humans

1995 ◽  
Vol 79 (6) ◽  
pp. 2154-2162 ◽  
Author(s):  
C. S. Fulco ◽  
S. F. Lewis ◽  
P. N. Frykman ◽  
R. Boushel ◽  
S. Smith ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Biceps Femoris ◽  
Knee Extension ◽  
Quadriceps Femoris ◽  
Work Rate ◽  
Myoelectric Activity ◽  
Work Intensity ◽  
O2 Uptake ◽  
Constant Work Rate ◽  
Leg Exercise

There is virtually no published information on muscle fatigue, defined as a gradual decline in force-generating capacity, during conventional dynamic (D) leg exercise. To quantitate progression of fatigue, we developed 1) a model featuring integration of maximal voluntary static contraction (MVC) of knee extension (KE) muscles with ongoing DKE and 2) a device that allows frequent rapid transfer between DKE isolated to the quadriceps femoris muscles and measurement of KE MVC. Eight healthy men performed graded and submaximal constant work rate one-leg DKE to exhaustion while seated. Work rate, a product of a contraction rate (1 Hz), force measured at the ankle, and distance of ankle movement from 90 degrees to 150 degrees of KE, was precisely controlled. Lack of rise in myoelectric activity in biceps femoris of the active leg during DKE and MVC was consistent with restriction of muscle action to quadriceps femoris. The slope of the linear relationship between O2 uptake and work rate was 13.7 ml O2/W (r = 0.93). This slope and the increase of heart rate relative to increasing work intensity agreed with published values for D leg exercise. Test-retest values for O2 uptake were similar (P > 0.05) for matched DKE work rates. To track fatigue, MVC (90 degrees knee angle) was performed every 2 min of DKE. After 4 min of DKE at work rates corresponding to (mean +/- SE) 66 +/- 2, 78 +/- 2, and 100% of peak DKE O2 uptake, MVC fell to 95 +/- 3, 90 +/- 5, and 65 +/- 7%* of MVC of rested muscle, respectively (*P < 0.01 from previous work rates). Virtually identical declines in MVC were observed by the end of graded work rate DKE and submaximal constant work rate DKE tests. Quantitation of progressive muscle fatigue during D leg exercise provides a framework to study the effects of a variety of interventions on the fatigue process and may permit unique insights into the involved mechanisms.

scholarly journals Oxygen uptake dynamics during high-intensity exercise in children and adults

1991 ◽  
Vol 70 (2) ◽  
pp. 841-848 ◽  
Author(s):  
Y. Armon ◽  
D. M. Cooper ◽  
R. Flores ◽  
S. Zanconato ◽  
T. J. Barstow
Keyword(s):  
High Intensity ◽  
Cycle Ergometer ◽  
Work Rate ◽  
High Intensity Exercise ◽  
O2 Uptake ◽  
Low Intensity ◽  
Ergometer Exercise ◽  
Constant Work Rate ◽  
The Difference ◽  
Low Intensity Exercise

We hypothesized that the O2 uptake (Vo2) response to high-intensity exercise would be different in children than in adults. To test this hypothesis, 22 children (6-12 yr old) and 7 adults (27-40 yr old) performed 6 min of constant-work-rate cycle-ergometer exercise. Sixteen children performed a single test above their anaerobic threshold (AT). In a separate protocol, six children and all adults exercised at low and high intensity. Low-intensity exercise corresponded to the work rate at 80% of each subject's AT. High-intensity exercise (above the AT) was determined first by calculating the difference in work rate between the AT and the maximal Vo2 (delta). Twenty-five, 50, and 75% of this difference were added to the work rate at the subject's AT, and these work rates were referred to as 25% delta, 50% delta, and 75% delta. For exercise at 50% delta and 75% delta, Vo2 increased throughout exercise (O2 drift, linear regression slope of Vo2 as a function of time from 3 to 6 min) in all the adults, and the magnitude of the drift was correlated with increasing work rates in the above-AT range (r = 0.91, P less than 0.0001). In contrast, no O2 drift was observed in over half of the children during above-AT exercise. The O2 drifts were much higher in adults (1.76 +/- 0.63 ml O2.kg-1.min-2 at 75% delta) than in children (0.20 +/- 0.42, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Early dynamics of O2 uptake and heart rate as affected by exercise work rate

1989 ◽  
Vol 67 (6) ◽  
pp. 2535-2541 ◽  
Author(s):  
K. E. Sietsema ◽  
J. A. Daly ◽  
K. Wasserman
Keyword(s):  
Heart Rate ◽  
Steady State ◽  
Phase I ◽  
Response Times ◽  
Normal Subjects ◽  
Work Rate ◽  
O2 Uptake ◽  
Constant Work Rate ◽  
Two Phases ◽  
Few Data

The kinetics of O2 uptake (Vo2) and heart rate (HR) in response to constant work rate exercise have been characterized as two phases, an immediate response as the result largely of abrupt hemodynamic changes and a slower response as the result of increases in both blood flow and arteriovenous O2 difference (avDo2). There are few data reported concerning Vo2 and HR during phase I or the relationship between their kinetics and work rate or intensity. Because phase I responses depend on abrupt cardiovascular adjustments, it was hypothesized that phase I increases in Vo2 and HR would be greater the more “fit” the subject and would be relatively independent of work rate. To test this, 10 normal subjects exercised from rest to each of five work rates ranging from unloaded cycling to 150 W. The phase I increases of Vo2, HR, and Vo2/HR had small but significant correlations with work rate but not with fitness. At very low work rates (unloaded cycling and 25 W), Vo2 and HR often exceeded their steady-state levels in phase I. There was therefore no phase II increase for Vo2 or HR at these work rates, the entire O2 requirement having been met by phase I circulatory adjustments. For all other work rates, mean response times for Vo2 and HR were related to fitness and were slower than those for Vo2/HR, suggesting that avDo2 reached a steady state before cardiac output did.

Comparative Measurement Properties of Constant Work-Rate Cycling and Endurance Shuttle Walking in Patients with COPD: Data from the TORRACTO Study

Pneumologie ◽  
2018 ◽  
Vol 72 (S 01) ◽  
pp. S90-S90
Author(s):  
K Siemon ◽  
F Maltais ◽  
DE O'Donnell ◽  
A Hamilton ◽  
Y Zhao ◽  
...  
Keyword(s):  
Work Rate ◽  
Measurement Properties ◽  
Comparative Measurement ◽  
Constant Work Rate

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.

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