Pulmonary oxygen uptake kinetics

2017 ◽  
Author(s):  
Alan R Barker ◽  
Neil Armstrong
Keyword(s):  
Oxygen Uptake ◽  
Oxidative Phosphorylation ◽  
Children And Adolescents ◽  
Phase Ii ◽  
Slow Component ◽  
Moderate Intensity ◽  
Heavy Exercise ◽  
Moderate Intensity Exercise ◽  
Pulmonary Oxygen Uptake ◽  
Age Related

The pulmonary oxygen uptake (pV̇O2) kinetic response to exercise provides valuable non-invasive insight into the control of oxidative phosphorylation and determinants of exercise tolerance in children and adolescents. Few methodologically robust studies have investigated pV̇O2 kinetics in children and adolescents, but age- and sex-related differences have been identified. There is a clear age-related slowing of phase II pV̇O2 kinetics during heavy and very heavy exercise, with a trend showing during moderate intensity exercise. During heavy and very heavy exercise the oxygen cost is higher for phase II and the pV̇O2 component is truncated in children. Sex-related differences occur during heavy, but not moderate, intensity exercise, with boys having faster phase II pV̇O2 kinetics and a smaller pV̇O2 slow component compared to girls. The mechanisms underlying these differences are likely related to changes in phosphate feedback controllers of oxidative phosphorylation, muscle oxygen delivery, and/or muscle fibre recruitment strategies.

Influence of exercise intensity on pulmonary oxygen uptake kinetics at the onset of exercise and recovery in male adolescents

2008 ◽  
Vol 33 (1) ◽  
pp. 107-117 ◽  
Author(s):  
Nicola Lai ◽  
Melita M. Nasca ◽  
Marco A. Silva ◽  
Fatima T. Silva ◽  
Brian J. Whipp ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Slow Component ◽  
Work Rate ◽  
Moderate Intensity ◽  
Heavy Exercise ◽  
Pulmonary Oxygen Uptake ◽  
Square Wave ◽  
Male Adolescents ◽  
Double Exponential ◽  
Single Exponential

The dynamics of the pulmonary oxygen uptake (VO2) responses to square-wave changes in work rate can provide insight into bioenergetic processes sustaining and limiting exercise performance. The dynamic responses at the onset of exercise and during recovery have been investigated systematically and are well characterized at all intensities in adults; however, they have not been investigated completely in adolescents. We investigated whether adolescents display a slow component in their VO2 on- and off-kinetic responses to heavy- and very heavy-intensity exercise, as demonstrated in adults. Healthy African American male adolescents (n = 9, 14–17 years old) performed square-wave transitions on a cycle ergometer (from and to a baseline work rate of 20 W) to work rates of moderate (M), heavy (H), and very heavy (VH) intensity. In all subjects, the VO2 on-kinetics were best described with a single exponential at moderate intensity (τ1, on = 36 ± 11 s) and a double exponential at heavy (τ1, on = 29 ± 9 s; τ2, on = 197 ± 92 s) and very heavy (τ1, on = 36 ± 9 s; τ2, on = 302 ± 14 s) intensities. In contrast, the VO2 off-kinetics were best described with a single exponential at moderate (τ1, off = 48 ± 9 s) and heavy (τ1, off = 53 ± 7 s) intensities and a double exponential at very heavy (τ1, off = 51 ± 3 s; τ2, off = 471 ± 54 s) intensity. In summary, adolescents consistently displayed a slow component during heavy exercise (on- but not off- transition) and very heavy exercise (on- and off-transitions). Although the overall response dynamics in adolescents were similar to those previously observed in adults, their specific characterizations were different, particularly the lack of symmetry between the on- and off-responses.

Oxygen Uptake Kinetics in Children and Adolescents: A Review

2009 ◽  
Vol 21 (2) ◽  
pp. 130-147 ◽  
Author(s):  
Neil Armstrong ◽  
Alan R. Barker
Keyword(s):  
Oxygen Uptake ◽  
Children And Adolescents ◽  
Phase Ii ◽  
Slow Component ◽  
Fiber Type ◽  
Muscle Metabolism ◽  
Oxygen Uptake Kinetics ◽  
Exponential Phase ◽  
Future Research ◽  
Age Related

The pulmonary oxygen uptake (pVO2) kinetic response at the onset of exercise provides a noninvasive window into the metabolic activity of the muscle and a valuable means of increasing our understanding of developmental muscle metabolism. However, to date only limited research has been devoted to investigating the pVO2 kinetic response during exercise in children and adolescents. From the rigorous studies that have been conducted, both age- and sex-related differences have been identified. Specifically, children display a faster exponential rise in the phase II pVO2 kinetics, which are purported to reflect the rise in muscle O2 consumption, during moderate, heavy and very heavy intensity exercise compared with adults. Furthermore, for heavy and very heavy exercise, the O2 cost of exercise is higher for the exponential phase and the magnitude of the pVO2 slow component is smaller in young children. Sex-related differences have been identified during heavy, but not moderate exercise, with prepubertal boys displaying a faster exponential phase II pVO2 kinetic response and a smaller pVO2 slow component compared with prepubertal girls. The mechanisms underlying these differences are currently poorly understood, and form the basis for future research in this area. However, it is hypothesized that an age-related modulation of the muscle phosphate feedback controllers to signal an increased rate of oxidative phosphorylation and/or altered muscle fiber type recruitment strategies have the potential to play an important role. Overall, the data support the view that at the onset of exercise children have an enhanced potential for oxidative metabolism in the myocyte compared with adults.

Influence of exercise intensity on pulmonary oxygen uptake kinetics in young and late middle-aged adults

2012 ◽  
Vol 303 (8) ◽  
pp. R791-R798 ◽  
Author(s):  
Melitta A. McNarry ◽  
Michael I. C. Kingsley ◽  
Michael J. Lewis
Keyword(s):  
Gas Exchange ◽  
Oxygen Uptake ◽  
Phase Ii ◽  
Slow Component ◽  
Primary Component ◽  
Oxygen Availability ◽  
Large Sample Size ◽  
Heavy Exercise ◽  
Middle Aged ◽  
Pulmonary Oxygen Uptake

It is unclear whether pulmonary oxygen uptake (V̇o2) kinetics demonstrate linear, first-order behavior during supra gas exchange threshold exercise. Resolution of this issue is pertinent to the elucidation of the factors regulating oxygen uptake (V̇o2) kinetics, with oxygen availability and utilization proposed as putative mediators. To reexamine this issue with the advantage of a relatively large sample size, 50 young (24 ± 4 yr) and 15 late middle-aged (54 ± 3 yr) participants completed repeated bouts of moderate and heavy exercise. Pulmonary gas exchange, heart rate (HR), and cardiac output (Q̇) variables were measured throughout. The phase II τ was slower during heavy exercise in both young (moderate: 22 ± 9; heavy: 29 ± 9 s; P ≤ 0.001) and middle-aged (moderate: 22 ± 9; heavy: 30 ± 8 s; P ≤ 0.001) individuals. The HR τ was slower during heavy exercise in young (moderate: 33 ± 10; heavy: 44 ± 15 s; P ≤ 0.05) and middle-aged (moderate: 30 ± 12; heavy: 50 ± 20 s; P ≤ 0.05) participants, and the Q̇ τ showed a similar trend (young moderate: 21 ± 13; heavy: 28 ± 16 s; middle-aged moderate: 32 ± 13; heavy: 40 ± 15 s; P ≥ 0.05). There were no differences in primary component V̇o2 kinetics between age groups, but the middle-aged group had a significantly reduced V̇o2 slow component amplitude in both absolute (young: 0.25 ± 0.09; middle-aged: 0.11 ± 0.06 l/min; P ≤ 0.05) and relative terms (young: 15 ± 10; middle-aged: 9 ± 4%; P ≤ 0.05). Thus V̇o2 kinetics do not demonstrate dynamic linearity during heavy intensity exercise. Speculatively, the slower phase II τ during heavy exercise might be attributable to reduced oxygen availability. Finally, the primary and slow components of V̇o2 kinetics appear to be differentially influenced by middle age.

The Effect of Prior Moderate- and Heavy-Intensity Running on the VO2 Response to Exhaustive Severe-Intensity Running

2006 ◽  
Vol 1 (4) ◽  
pp. 361-374 ◽  
Author(s):  
Stephen B. Draper ◽  
Dan M. Wood ◽  
Jo Corbett ◽  
David V.B. James ◽  
Christopher R. Potter
Keyword(s):  
Oxygen Uptake ◽  
Slow Component ◽  
Maximum Oxygen Uptake ◽  
Moderate Intensity ◽  
Time To Exhaustion ◽  
Heavy Exercise ◽  
Square Wave ◽  
Severe Intensity ◽  
The Difference ◽  
Trained Runners

We tested the hypothesis that prior heavy-intensity exercise reduces the difference between asymptotic oxygen uptake (VO2) and maximum oxygen uptake (VO2max) during exhaustive severe-intensity running lasting ≍2 minutes. Ten trained runners each performed 2 ramp tests to determine peak VO2 (VO2peak) and speed at venti-latory threshold. They performed exhaustive square-wave runs lasting ≍2 minutes, preceded by either 6 minutes of moderate-intensity running and 6 minutes rest (SEVMOD) or 6 minutes of heavy-intensity running and 6 minutes rest (SEVHEAVY). Two transitions were completed in each condition. VO2 was determined breath by breath and averaged across the 2 repeats of each test; for the square-wave test, the averaged VO2 response was then modeled using a monoexponential function. The amplitude of the VO2 response to severe-intensity running was not different in the 2 conditions (SEVMOD vs SEVHEAVY; 3925 ± 442 vs 3997 ± 430 mL/min, P = .237), nor was the speed of the response (τ; 9.2 ± 2.1 vs 10.0 ± 2.1 seconds, P = .177). VO2peak from the square-wave tests was below that achieved in the ramp tests (91.0% ± 3.2% and 92.0% ± 3.9% VO2peak, P < .001). There was no difference in time to exhaustion between conditions (110.2 ± 9.7 vs 111.0 ± 15.2 seconds, P = .813). The results show that the primary VO2 response is unaffected by prior heavy exercise in running performed at intensities at which exhaustion will occur before a slow component emerges.

scholarly journals PO-098 Effect of HIIT on mitochondrial telomerase of skeletal muscle in aged rats

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
Yiyi Liu ◽  
Hao Su ◽  
Zhongye Jiang ◽  
Tianhao Wen ◽  
Jia Shao
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Uptake ◽  
Intervention Group ◽  
Exercise Group ◽  
Moderate Intensity ◽  
Control Group ◽  
Moderate Intensity Exercise ◽  
Aging Rats ◽  
Age Related ◽  
Significant Difference

Objective The HIIT and moderate-intensity exercise are two different exercise models among the public fitness. In recent years, HIIT become more and more popular, unfortunately, there is a tremendous lack of research being done effects of mitochondrial reverse transcriptase (TERT) on age-related degeneration of skeletal muscle by HIIT. The purpose of this study was to compare the HIIT group and moderate-intensity group, and research difference of telomerase expression and cardiopulmonary endurance between the exercise group and the quiet control group was discussed. Methods  fifty-nine male Wistar rats were divided into three groups at random: control group (Q=19), moderate-intensity intervention group (M=20), and HIIT intervention group (H=20). The rats in Q group did not any exercise, and the rats in M group developed the exercise with 60% VO2max intensity for 8 weeks. H group did a training program for an 8-week exercise with alternating 40%, 60%, and 80% VO2max intensities. The rats in the experimental group were exercised for 50 minutes every day and trained for 5 days per week. After the baseline value group was sampled, each group of rats was selected after the training reached the specified number of weeks (4 and 8 weeks), and the maximum oxygen uptake test was performed before the material was taken. Single factor analysis of variance were used to assess differences in VO2max, and expression of protein between conditions. Results It was found that H group VO2max was significantly higher than M group and Q group (P<0.05). At same time, the mTERT expression of the M group at the 4th week was significantly higher than that of the Q group (P<0.05). The mTERT expression in group H was significantly higher than that in group Q at week 8 (P<0.05).There was no significant difference between the H group and the Q group at 8th week (P<0.05). Conclusions 1. HIIT exercise lasting for 8 weeks can effectively inhibit the decrease of maximal oxygen uptake in aging rats compared with moderate exercise. 2. HIIT training for 8 weeks promotes the expression of mTERT; 3. The maintenance of VO2max in aging rats may be related to the enhancement of mitochondrial antioxidant function by HIIT-promoted TERT to mitochondrial translocation.

Muscle phosphocreatine and pulmonary oxygen uptake kinetics in children at the onset and offset of moderate intensity exercise

2008 ◽  
Vol 102 (6) ◽  
pp. 727-738 ◽  
Author(s):  
Alan R. Barker ◽  
Joanne R. Welsman ◽  
Jonathan Fulford ◽  
Deborah Welford ◽  
Craig A. Williams ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Uptake Kinetics ◽  
Uptake Kinetics ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Pulmonary Oxygen Uptake

scholarly journals Effects of prior heavy exercise on phase II pulmonary oxygen uptake kinetics during heavy exercise

2000 ◽  
Vol 89 (4) ◽  
pp. 1387-1396 ◽  
Author(s):  
Mark Burnley ◽  
Andrew M. Jones ◽  
Helen Carter ◽  
Jonathan H. Doust
Keyword(s):  
Oxygen Uptake ◽  
Phase Ii ◽  
Slow Component ◽  
Exercise Bout ◽  
Oxygen Uptake Kinetics ◽  
Cycle Ergometer ◽  
Moderate Exercise ◽  
Heavy Exercise ◽  
Mean Response Time ◽  
The Mean

We tested the hypothesis that heavy-exercise phase II oxygen uptake (V˙o 2) kinetics could be speeded by prior heavy exercise. Ten subjects performed four protocols involving 6-min exercise bouts on a cycle ergometer separated by 6 min of recovery: 1) moderate followed by moderate exercise; 2) moderate followed by heavy exercise; 3) heavy followed by moderate exercise; and 4) heavy followed by heavy exercise. The V˙o 2 responses were modeled using two (moderate exercise) or three (heavy exercise) independent exponential terms. Neither moderate- nor heavy-intensity exercise had an effect on the V˙o 2 kinetic response to subsequent moderate exercise. Although heavy-intensity exercise significantly reduced the mean response time in the second heavy exercise bout (from 65.2 ± 4.1 to 47.0 ± 3.1 s; P < 0.05), it had no significant effect on either the amplitude or the time constant (from 23.9 ± 1.9 to 25.3 ± 2.9 s) of theV˙o 2 response in phase II. Instead, this “speeding” was due to a significant reduction in the amplitude of the V˙o 2 slow component. These results suggest phase II V˙o 2 kinetics are not speeded by prior heavy exercise.

Muscle damage slows oxygen uptake kinetics during moderate-intensity exercise performed at high pedal rate

2011 ◽  
Vol 36 (6) ◽  
pp. 848-855 ◽  
Author(s):  
Renato Molina ◽  
Benedito Sérgio Denadai
Keyword(s):  
Oxygen Uptake ◽  
Muscle Damage ◽  
Phase Ii ◽  
Oxygen Uptake Kinetics ◽  
Cycle Ergometer ◽  
Moderate Intensity ◽  
Isokinetic Dynamometer ◽  
Moderate Intensity Exercise ◽  
Exercise Induced ◽  
Type Ii Fibers

This study aimed to investigate the dependence of oxygen uptake (VO2) kinetics on pedal cadence during moderate-intensity exercise following exercise-induced muscle damage (EIMD). Twenty untrained males were randomly assigned to a 50 revolution per minute (rpm) (age, 23.3 ± 1.8 years; VO2max, 38.9 ± 2.8 mL·kg–1·min–1) or 100 rpm group (age, 24.4 ± 3.5 years, VO2max, 42.9 ± 4.3 mL·kg–1·min–1). Participants completed “step” tests to moderate-intensity exercise from an unloaded baseline on a cycle ergometer before (baseline) and at 24 and 48 h after muscle-damaging exercise (10 sets of 10 eccentric contractions performed on an isokinetic dynamometer with a 2-min rest between each set). Pedal cadence was kept constant throughout each cycling trial (50 or 100 rpm). There were no changes in phase II pulmonary VO2 kinetics following EIMD for the 50 rpm group (baseline = 35 ± 4 s; 24 h = 35 ± 7 s; and 48 h = 36 ± 9 s). However, the phase II VO2 was significantly greater at 24 h (59 ± 27 s) compared with baseline (39 ± 6 s) and 48 h (40 ± 9 s) for the 100 rpm group. It is concluded that the effects of EIMD on phase II VO2 kinetics during moderate-intensity cycling exercise is dependent on pedal cadence. The slower VO2 kinetics after muscle damage suggests that type II fibers are involved during transition to moderate-intensity exercise at high pedal cadence.

Impaired pulmonary oxygen uptake kinetics and reduced peak aerobic power during small muscle mass exercise in heart transplant recipients

2007 ◽  
Vol 103 (5) ◽  
pp. 1722-1727 ◽  
Author(s):  
Nicholas G. Jendzjowsky ◽  
Corey R. Tomczak ◽  
Richard Lawrance ◽  
Dylan A. Taylor ◽  
Wayne J. Tymchak ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Uptake ◽  
Phase Ii ◽  
Heart Transplant ◽  
Moderate Intensity ◽  
Peak Exercise ◽  
Transplant Recipients ◽  
Pulmonary Oxygen Uptake ◽  
Significant Difference ◽  
Heart Transplant Recipients

We examined peak and reserve cardiovascular function and skeletal muscle oxygenation during unilateral knee extension (ULKE) exercise in five heart transplant recipients (HTR, mean ± SE; age: 53 ± 3 years; years posttransplant: 6 ± 4) and five age- and body mass-matched healthy controls (CON). Pulmonary oxygen uptake (V̇o2p), heart rate (HR), stroke volume (SV), cardiac output (Q̇), and skeletal muscle deoxygenation (HHb) kinetics were assessed during moderate-intensity ULKE exercise. Peak exercise and reserve V̇o2p, Q̇, and systemic arterial-venous oxygen difference (a-vO2diff) were 23–52% lower ( P < 0.05) in HTR. The reduced Q̇ and a-vO2diff reserves were associated with lower HR and HHb reserves, respectively. The phase II V̇o2p time delay was greater (HTR: 38 ± 2 vs. CON: 25 ± 1 s, P < 0.05), while time constants for phase II V̇o2p (HTR: 54 ± 8 vs. CON: 31 ± 3 s), Q̇ (HTR: 66 ± 8 vs. CON: 28 ± 4 s), and HHb (HTR: 27 ± 5 vs. CON: 13 ± 3 s) were significantly slower in HTR. The HR half-time was slower in HTR (113 ± 21 s) vs. CON (21 ± 2 s, P < 0.05); however, no significant difference was found between groups for SV kinetics (HTR: 39 ± 8 s vs. CON 31 ± 6 s). The lower peak V̇o2p and prolonged V̇o2p kinetics in HTR were secondary to impairments in both cardiovascular and skeletal muscle function that result in reduced oxygen delivery and utilization by the active muscles.

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