Oxygen uptake kinetics in endurance-trained and untrained postmenopausal women

2013 ◽  
Vol 38 (2) ◽  
pp. 154-160 ◽  
Author(s):  
Shilpa Dogra ◽  
Matthew D. Spencer ◽  
Juan M. Murias ◽  
Donald H. Paterson
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Older Women ◽  
Near Infrared ◽  
Ventilatory Threshold ◽  
Vastus Lateralis ◽  
Hemoglobin Concentration ◽  
Oxygen Uptake Kinetics ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise

The rate of adjustment for pulmonary oxygen uptake (τV̇O2p) is slower in untrained and in older adults. Near-infrared spectroscopy (NIRS) has shed light on potential mechanisms underlying this in young men and women and in older men; however, there is no such data available in older women. The purpose of this study was to gain a better understanding of the mechanisms of slower τV̇O2p in older women who were either endurance-trained or untrained. Endurance-trained (n = 10; age, 62.6 ± 1.0 years) and untrained (n = 9; age, 69.1 ± 2.2 years) older women attended 2 maximal and 2 submaximal (90% of ventilatory threshold) exercise sessions. Oxygen uptake (V̇O2) was measured breath by breath, using a mass spectrometer, and changes in deoxygenated hemoglobin concentration of the vastus lateralis ([HHb]) were measured using NIRS. Heart rate was measured continuously with a 3-lead electrocardiogram. τV̇O2p was faster in trained (35.1 ± 5.5 s) than in untrained (57.0 ± 8.1 s) women. The normalized [HHb] to V̇O2 ratio, an indicator of muscle O2 delivery to O2 utilization, indicated a smaller overshoot in trained (1.09 ± 0.1) than in untrained (1.39 ± 0.1) women. Heart rate data indicated a faster adjustment of heart rate in trained (33.0 ± 13.0) than in untrained (68.7 ± 14.1) women. The pairing of V̇O2p data with NIRS-derived [HHb] data indicates that endurance-trained older women likely have better matching of O2 delivery to O2 utilization than older untrained women during moderate-intensity exercise, leading to a more rapid adjustment of V̇O2p.

Moderate and heavy oxygen uptake kinetics in postmenopausal women

2009 ◽  
Vol 34 (6) ◽  
pp. 1065-1072 ◽  
Author(s):  
Liza Stathokostas ◽  
John M. Kowalchuk ◽  
Robert J. Petrella ◽  
Donald H. Paterson
Keyword(s):  
Oxygen Uptake ◽  
Postmenopausal Women ◽  
Older Women ◽  
Ventilatory Threshold ◽  
Hormone Replacement ◽  
Oxygen Uptake Kinetics ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Repeated Exercise ◽  
Exercise Transitions

The lack of estrogen in postmenopausal women not using hormone replacement therapy (HRT), compared with those using HRT, may reduce submaximal blood flow during exercise and result in an oxygen delivery limitation constraining oxygen uptake (VO2) kinetics. The adaptation of pulmonary VO2 (VO2p) during the transition to exercise in older women was examined in this study. Thirty-one healthy postmenopausal women (mean age, 61 ± 6 years), 15 not using HRT and 16 using HRT, performed repeated exercise transitions (6 min) on a cycle, to work rates corresponding to 80% of estimated ventilatory threshold (moderate-intensity exercise) and to Δ50 (heavy-intensity exercise). There was no difference in moderate-intensity τVO2p between non-HRT (40 ± 9 s) and HRT (41 ± 9 s) women. Similarly, there was no difference in heavy-intensity τVO2p between non-HRT (44 ± 8 s) and HRT (45 ± 8 s) women. Thus, HRT did not affect the slowing of VO2 kinetics of older women.

scholarly journals Limitations of skeletal muscle oxygen delivery and utilization during moderate-intensity exercise in moderately impaired patients with chronic heart failure

2016 ◽  
Vol 311 (6) ◽  
pp. H1530-H1539 ◽  
Author(s):  
Victor M. Niemeijer ◽  
Ruud F. Spee ◽  
Thijs Schoots ◽  
Pieter F. F. Wijn ◽  
Hareld M. C. Kemps
Keyword(s):  
Heart Failure ◽  
Skeletal Muscle ◽  
Chronic Heart Failure ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Oxygen Uptake Kinetics ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Exercise Tests ◽  
Mean Response Time

The extent and speed of transient skeletal muscle deoxygenation during exercise onset in patients with chronic heart failure (CHF) are related to impairments of local O2 delivery and utilization. This study examined the physiological background of submaximal exercise performance in 19 moderately impaired patients with CHF (Weber class A, B, and C) compared with 19 matched healthy control (HC) subjects by measuring skeletal muscle oxygenation (SmO2) changes during cycling exercise. All subjects performed two subsequent moderate-intensity 6-min exercise tests (bouts 1 and 2) with measurements of pulmonary oxygen uptake kinetics and SmO2 using near-infrared spatially resolved spectroscopy at the vastus lateralis for determination of absolute oxygenation values, amplitudes, kinetics (mean response time for onset), and deoxygenation overshoot characteristics. In CHF, deoxygenation kinetics were slower compared with HC (21.3 ± 5.3 s vs. 16.7 ± 4.4 s, P < 0.05, respectively). After priming exercise (i.e., during bout 2), deoxygenation kinetics were accelerated in CHF to values no longer different from HC (16.9 ± 4.6 s vs. 15.4 ± 4.2 s, P = 0.35). However, priming did not speed deoxygenation kinetics in CHF subjects with a deoxygenation overshoot, whereas it did reduce the incidence of the overshoot in this specific group ( P < 0.05). These results provide evidence for heterogeneity with respect to limitations of O2 delivery and utilization during moderate-intensity exercise in patients with CHF, with slowed deoxygenation kinetics indicating a predominant O2 utilization impairment and the presence of a deoxygenation overshoot, with a reduction after priming in a subgroup, indicating an initial O2 delivery to utilization mismatch.

Effects of acute hypoxia on the oxygen uptake kinetics of older adults during cycling exercise

2012 ◽  
Vol 37 (4) ◽  
pp. 744-752 ◽  
Author(s):  
Livio Zerbini ◽  
Alfredo Brighenti ◽  
Barbara Pellegrini ◽  
Lorenzo Bortolan ◽  
Tommaso Antonetti ◽  
...  
Keyword(s):  
Older Adults ◽  
Oxygen Uptake ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Oxygen Uptake Kinetics ◽  
Uptake Kinetics ◽  
Moderate Intensity ◽  
Vastus Lateralis Muscle ◽  
Incremental Test ◽  
Square Wave

Pulmonary oxygen uptake, heart rate (HR), and deoxyhemoglobin (HHb) kinetics were studied in a group of older adults exercising in hypoxic conditions. Fourteen healthy older adults (aged 66 ± 6 years) performed 4 exercise sessions that consisted of (i) an incremental test to exhaustion on a cycloergometer while breathing normoxic room air (fractional inspired oxygen (FiO2) = 20.9% O2); (ii) an incremental test to exhaustion on a cycloergometer while breathing hypoxic room air (FiO2 = 15% O2); (iii) 3 repeated square wave cycling exercises at moderate intensity while breathing normoxic room air; and (iv) 3 repeated square wave cycling exercises at moderate intensity while breathing hypoxic room air. During all exercise sessions, pulmonary gas exchange was measured breath-by-breath; HHb was determined on the vastus lateralis muscle by near-infrared spectroscopy; and HR was collected beat-by-beat. The pulomary oxygen uptake kinetics became slower in hypoxia (31 ± 9 s) than in normoxia (27 ± 7 s) because of an increased mismatching between O2 delivery to O2 utilization at the level of the muscle. The HR and HHb kinetics did not change between hypoxia and normoxia,

scholarly journals Effect of creatine supplementation on oxygen uptake kinetics during submaximal cycle exercise

2002 ◽  
Vol 92 (6) ◽  
pp. 2571-2577 ◽  
Author(s):  
Andrew M. Jones ◽  
Helen Carter ◽  
Jamie S. M. Pringle ◽  
Iain T. Campbell
Keyword(s):  
Oxygen Uptake ◽  
Ventilatory Threshold ◽  
Vastus Lateralis ◽  
Creatine Supplementation ◽  
Oxygen Uptake Kinetics ◽  
Primary Component ◽  
Heavy Exercise ◽  
Cycle Exercise ◽  
Oral Consumption ◽  
Type Ii Fibers

The purpose of this study was to test the effect of oral creatine (Cr) supplementation on pulmonary oxygen uptake (V˙o 2) kinetics during moderate [below ventilatory threshold (VT)] and heavy (above VT) submaximal cycle exercise. Nine subjects (7 men; means ± SD: age 28 ± 3 yr, body mass 73.2 ± 5.6 kg, maximalV˙o 2 46.4 ± 8.0 ml · kg−1 · min−1) volunteered to participate in this study. Subjects performed transitions of 6-min duration from unloaded cycling to moderate (80% VT; 8–12 repeats) and heavy exercise (50% change; i.e., halfway between VT and maximal V˙o 2; 4–6 repeats), both in the control condition and after Cr loading, in a crossover design. The Cr loading regimen involved oral consumption of 20 g/day of Cr monohydrate for 5 days, followed by a maintenance dose of 5 g/day thereafter. V˙o 2 was measured breath by breath and modeled by using two (moderate) or three (heavy) exponential terms. For moderate exercise, there were no differences in the parameters of the V˙o 2 kinetic response between control and Cr-loaded conditions. For heavy exercise, the time-based parameters of the V˙o 2response were unchanged, but the amplitude of the primary component was significantly reduced with Cr loading (means ± SE: control 2.00 ± 0.12 l/min; Cr loaded 1.92 ± 0.10 l/min; P < 0.05) as was the end-exerciseV˙o 2 (control 2.19 ± 0.13 l/min; Cr loaded 2.12 ± 0.14 l/min; P < 0.05). The magnitude of the reduction in submaximalV˙o 2 with Cr loading was significantly correlated with the percentage of type II fibers in the vastus lateralis ( r = 0.87; P < 0.01; n = 7), indicating that the effect might be related to changes in motor unit recruitment patterns or the volume of muscle activated.

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 Similar pattern of change in V̇o2 kinetics, vascular function, and tissue oxygen provision following an endurance training stimulus in older and young adults

2017 ◽  
Vol 312 (4) ◽  
pp. R467-R476 ◽  
Author(s):  
Kaitlin M. McLay ◽  
Juan M. Murias ◽  
Donald H. Paterson
Keyword(s):  
Exercise Training ◽  
Vascular Function ◽  
Time Course ◽  
Near Infrared ◽  
Training Stimulus ◽  
Hemoglobin Concentration ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Similar Time ◽  
Endurance Cycling

The purpose of this study was to examine the time course of changes in the oxygen uptake (V̇o2) kinetics response subsequent to short-term exercise training (i.e., 24, 48, 72, and 120 h posttraining) and examine the relationship with the time course of changes in microvascular [deoxygenated hemoglobin concentration ([HHb])-to-V̇o2 ratio ([HHb])/V̇o2)] and macrovascular [flow-mediated dilation (FMD)] O2 delivery to the active tissues/limbs. Seven healthy older [OA; 74 ± 6 (SD) yr] and young men (YA; 25 ± 3 yr) completed three endurance cycling exercise training sessions at 70% V̇o2peak. Moderate-intensity exercise on-transient V̇o2 (measured breath by breath) and [HHb] (measured by near-infrared spectroscopy) were modeled with a monoexponential and normalized (0–100% of response), and the [HHb])/V̇o2 was calculated. Ultrasound-derived FMD of the popliteal artery was assessed after 5 min of cuff occlusion. %FMD was calculated as the greatest percent change in diameter from baseline. Time constant of V̇o2 (τV̇o2) was significantly reduced in both OA (~18%) and YA (~23%) at 24 h ( P < 0.001) posttraining and remained decreased at 48 h before returning toward pretraining (PRE) values. Both groups showed a significant decrease in the [HHb])/V̇o2 at 24, 48, and 72 h ( P = 0.001, 0.01, and 0.03, respectively) posttraining before returning toward PRE values at 120 h. %FMD followed a similar time course to that of changes in the [HHb])/V̇o2, being significantly greater in both OA (by ~64%) and YA (by ~26%) at 24 h ( P < 0.001), remaining increased at 48 and 72 h ( P = 0.02 and 0.03, respectively), and returning toward PRE values at 120 h. These data suggest the rate of adjustment of V̇o2 may be constrained by O2 availability in the active tissues.

Relationship between pulmonary O2 uptake kinetics and muscle deoxygenation during moderate-intensity exercise

2003 ◽  
Vol 95 (1) ◽  
pp. 113-120 ◽  
Author(s):  
Darren S. DeLorey ◽  
John M. Kowalchuk ◽  
Donald H. Paterson
Keyword(s):  
Near Infrared ◽  
Vastus Lateralis ◽  
Metabolic Activation ◽  
Moderate Intensity ◽  
Vastus Lateralis Muscle ◽  
Phase 2 ◽  
Moderate Intensity Exercise ◽  
Muscle Deoxygenation ◽  
Monoexponential Model ◽  
Kinetics Of

The temporal relationship between the kinetics of phase 2 pulmonary O2 uptake (V̇o2p) and deoxygenation of the vastus lateralis muscle was examined during moderate-intensity leg-cycling exercise. Young adults (5 men, 6 women; 23 ± 3 yr; mean ± SD) performed repeated transitions on 3 separate days from 20 W to a constant work rate corresponding to 80% of lactate threshold. Breath-by-breath V̇o2p was measured by mass spectrometer and volume turbine. Deoxyhemoglobin (HHb), oxyhemoglobin, and total hemoglobin and myoglobin were sampled each second by near-infrared spectroscopy (Hamamatsu NIRO-300). V̇o2p data were filtered, interpolated to 1 s, and averaged to 5-s bins; HHb data were averaged to 5-s bins. Phase 2 V̇o2p data were fit with a monoexponential model. For HHb, a time delay (TDHHb) from exercise onset to an increase in HHb was determined, and thereafter data were fit with a monoexponential model. The time constant for V̇o2p (30 ± 8 s) was slower ( P < 0.01) than that for HHb (10 ± 3 s). The TDHHb before an increase in HHb was 13 ± 2 s. The possible mechanisms of the TDHHb are discussed with reference to metabolic activation and matching of local muscle O2 delivery and O2 utilization. After this initial TDHHb, the kinetics of local muscle deoxygenation were faster than those of phase 2 V̇o2p (and presumably muscle O2 consumption), reflecting increased O2 extraction and a mismatch between local muscle O2 consumption and perfusion.

scholarly journals Adjustments of pulmonary O2 uptake and muscle deoxygenation during ramp incremental exercise and constant-load moderate-intensity exercise in young and older adults

2012 ◽  
Vol 113 (9) ◽  
pp. 1466-1475 ◽  
Author(s):  
Braden M. R. Gravelle ◽  
Juan M. Murias ◽  
Matthew D. Spencer ◽  
Donald H. Paterson ◽  
John M. Kowalchuk
Keyword(s):  
Older Adults ◽  
Lactate Threshold ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Constant Load ◽  
Moderate Intensity ◽  
Sigmoid Function ◽  
Moderate Intensity Exercise ◽  
Muscle Deoxygenation ◽  
Age Related

The matching of muscle O2 delivery to O2 utilization can be inferred from the adjustments in muscle deoxygenation (Δ[HHb]) and pulmonary O2 uptake (V̇o2p). This study examined the adjustments of V̇o2p and Δ[HHb] during ramp incremental (RI) and constant-load (CL) exercise in adult males. Ten young adults (YA; age: 25 ± 5 yr) and nine older adults (OA; age: 70 ± 3 yr) completed two RI tests and six CL step transitions to a work rate (WR) corresponding to 1) 80% of the estimated lactate threshold (same relative WR) and 2) 50 W (same absolute WR). V̇o2p was measured breath by breath, and Δ[HHb] of the vastus lateralis was measured using near-infrared spectroscopy. Δ[HHb]-WR profiles were normalized from baseline (0%) to peak Δ[HHb] (100%) and fit using a sigmoid function. The sigmoid slope ( d) was greater ( P < 0.05) in OA (0.027 ± 0.01%/W) compared with YA (0.017 ± 0.01%/W), and the c/ d value (a value corresponding to 50% of the amplitude) was smaller ( P < 0.05) for OA (133 ± 40 W) than for YA (195 ± 51 W). No age-related differences in the sigmoid parameters were reported when WR was expressed as a percentage of peak WR. V̇o2p kinetics compared with Δ[HHb] kinetics for the 50-W transition were similar between YA and OA; however, Δ[HHb] kinetics during the transition to 80% of the lactate threshold were faster than V̇o2p kinetics in both groups. The greater reliance on O2 extraction displayed in OA during RI exercise suggests a lower O2 delivery-to-O2 utilization relationship at a given absolute WR compared with YA.

Faster oxygen uptake, heart rate, and ventilatory kinetics in stepping compared with cycle ergometry in patients with COPD during moderate-intensity exercise

2019 ◽  
Vol 44 (8) ◽  
pp. 879-885 ◽  
Author(s):  
Paulo de Tarso Müller ◽  
João Henrique Zardetti Nogueira ◽  
Tiago Rodrigues de Lemos Augusto ◽  
Gaspar Rogério Chiappa
Keyword(s):  
Heart Rate ◽  
Steady State ◽  
Oxygen Uptake ◽  
Minute Ventilation ◽  
Cycle Ergometry ◽  
Aerobic Performance ◽  
Moderate Intensity ◽  
Chronic Obstructive ◽  
Moderate Intensity Exercise ◽  
Time Constants

Step tests are a stressful and feasible cost-effective modality to evaluate aerobic performance. However, the eccentric in addition to concentric muscle contractions of the legs on stepping emerge as a potential speeding factor for cardioventilatory and metabolic adjustments towards a steady-state, since eccentric contractions would prompt an earlier and stronger mechanoreceptor activation, as well as higher heart rate/cardiac output adjustments to the same metabolic demand. Moreover, shorter tests are ideal for exercise-limited subjects. Nine subjects with chronic obstructive pulmonary disease were invited to participate in comprehensive lung function tests and constant work tests performed on different days at a 90% gas exchange threshold for 6 min, in single-step tests or cycle ergometry. After careful monoexponential regression modelling, statistically relevant faster phase II time constants for oxygen uptake (45 ± 18 s vs 53 ± 17 s, p = 0.017) and minute ventilation (61 ± 13 s vs 74 ± 17 s, p = 0.027) were observed in the 6-min step tests compared with cycle ergometry, respectively. Despite an absence of heart rate time constant difference (43 ± 20 s vs 69 ± 46 s, p = 0.167), there was a significantly faster rate constant toward a steady state for heart rate (p = 0.02). In addition, 4-min compared with 6-min analysis presented similar results (p > 0.05), providing an appropriate steady-state. We conclude that step tests might elicit faster time constants compared with cycle ergometry, at the same average metabolic level, and 4-min analysis has similar mean errors compared with 6-min analysis within an acceptable range. New studies, comprising mechanisms and detailed physiological backgrounds, are necessary.

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