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 Impact of l-citrulline supplementation on oxygen uptake kinetics during walking

2018 ◽  
Vol 43 (6) ◽  
pp. 631-637 ◽  
Author(s):  
John Ashley ◽  
Youngdeok Kim ◽  
Joaquin U. Gonzales
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Oxygen Uptake ◽  
Oxygen Uptake Kinetics ◽  
Uptake Kinetics ◽  
Oxygen Deficit ◽  
Moderate Intensity ◽  
Oxygen Cost ◽  
Cohen’S D ◽  
Cohen's D

Supplementation with l-citrulline (Cit) has been shown to improve muscle oxygenation and oxygen uptake kinetics during moderate- to high-intensity cycling in young men. The aim of this study was to test the hypothesis that Cit would improve oxygen uptake kinetics during walking in older and young adults. In a randomized, double-blind study, 26 (15 women, 11 men) adults between the ages of 20–35 years (n = 15) and 64–86 years (n = 11) completed 7-day periods of taking placebo and Cit (6 g/day) in a crossover manner. Participants walked on a treadmill at 40% heart rate reserve while pulmonary oxygen uptake was measured using indirect calorimetry. Net oxygen cost, mean response time (MRT), and the oxygen deficit were calculated before and after each supplement period. There was no significant change (P > 0.05) in net oxygen cost, MRT, or the oxygen deficit after Cit in older adults, while young adults showed a decrease (P = 0.05) in the oxygen deficit after Cit that tended (P = 0.053) to be different than the change after placebo. Sex-stratified analysis revealed that Cit decreased MRT (P = 0.04, Cohen’s d = 0.41) and the oxygen deficit (P < 0.01, Cohen’s d = 0.56) in men with the change after Cit being greater than the change after placebo (MRT: −4.5 ± 2.1 vs. 3.4 ± 2.1 s, P = 0.01; deficit: −0.15 ± 0.05 vs. 0.01 ± 0.05 L, P = 0.02). All oxygen uptake parameters were unchanged (P > 0.05) following Cit and placebo in women. Cit does not alter the oxygen cost of moderate-intensity walking in young or older adults, but Cit improved the rate of rise in oxygen uptake at exercise onset in men.

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.

Effects of prior heavy-intensity exercise on pulmonary O2 uptake and muscle deoxygenation kinetics in young and older adult humans

2004 ◽  
Vol 97 (3) ◽  
pp. 998-1005 ◽  
Author(s):  
Darren S. DeLorey ◽  
John M. Kowalchuk ◽  
Donald H. Paterson
Keyword(s):  
Older Adults ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Muscle Blood Flow ◽  
Moderate Intensity ◽  
Vastus Lateralis Muscle ◽  
Warm Up ◽  
Muscle Deoxygenation ◽  
Older Subjects ◽  
Young Subjects

Pulmonary O2 uptake (V̇o2p) and muscle deoxygenation kinetics were examined during moderate-intensity cycling (80% lactate threshold) without warm-up and after heavy-intensity warm-up exercise in young ( n = 6; 25 ± 3 yr) and older ( n = 5; 68 ± 3 yr) adults. We hypothesized that heavy warm-up would speed V̇o2p kinetics in older adults consequent to an improved intramuscular oxygenation. Subjects performed step transitions ( n = 4; 6 min) from 20 W to moderate-intensity exercise preceded by either no warm-up or heavy-intensity warm-up (6 min). V̇o2p was measured breath by breath. Oxy-, deoxy-(HHb), and total hemoglobin and myoglobin (Hbtot) of the vastus lateralis muscle were measured continuously by near-infrared spectroscopy (NIRS). V̇o2p (phase 2; τ) and HHb data were fit with a monoexponential model. After heavy-intensity warm-up, oxyhemoglobin (older subjects: 13 ± 9 μM; young subjects: 9 ± 8 μM) and Hbtot (older subjects: 12 ± 8 μM; young subjects: 14 ± 10 μM) were elevated ( P < 0.05) relative to the no warm-up pretransition baseline. In older adults, τV̇o2p adapted at a faster rate ( P < 0.05) after heavy warm-up (30 ± 7 s) than no warm-up (38 ± 5 s), whereas in young subjects, τV̇o2p was similar in no warm-up (26 ± 7 s) and heavy warm-up (25 ± 5 s). HHb adapted at a similar rate in older and young adults after no warm-up; however, in older adults after heavy warm-up, the adaptation of HHb was slower ( P < 0.01) compared with young and no warm-up. These data suggest that, in older adults, V̇o2p kinetics may be limited by a slow adaptation of muscle blood flow and O2 delivery.

Time-course of V̇O2 kinetics responses during moderate-intensity exercise subsequent to HIIT vs moderate-intensity continuous training in type 2 diabetes.

2021 ◽  
Author(s):  
Norita Gildea ◽  
Adam McDermott ◽  
Joel Rocha ◽  
Donal O'Shea ◽  
Simon Green ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Time Course ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Moderate Intensity ◽  
Vastus Lateralis Muscle ◽  
Maximal Heart Rate ◽  
Continuous Training ◽  
Muscle Deoxygenation

We assessed the time course of changes in oxygen uptake (V̇O2) and muscle deoxygenation (i.e., deoxygenated haemoglobin and myoglobin, [HHb+Mb]) kinetics during transitions to moderate-intensity cycling following 12-weeks of low-volume high-intensity interval training (HIIT) vs. moderate-intensity continuous training (MICT) in adults with type 2 diabetes (T2D). Participants were randomly assigned to MICT (n=10, 50 min of moderate-intensity cycling), HIIT (n=9, 10x1 min at ~90% maximal heart rate) or non-exercising control (n=9) groups. Exercising groups trained 3 times per week and measurements were taken every 3 weeks. [HHb+Mb] kinetics were measured by near-infrared spectroscopy at the vastus lateralis muscle. The local matching of O2 delivery to O2 utilization was assessed by the Δ[HHb+Mb]/ΔV̇O2ratio. The pretraining time constant of the primary phase of V̇O2 (τV̇O2p ) decreased (P<0.05) at wk 3 of training in both MICT (from 44±12 to 32±5 s) and HIIT (from 42±8 to 32 ± 4 s) with no further changes thereafter; while no changes were reported in controls. The pretraining overall dynamic response of muscle deoxygenation (τ'[HHb+Mb]) was faster than τV̇O2p in all groups, resulting in Δ[HHb+Mb]/V̇O2p showing a transient "overshoot" relative to the subsequent steady-state level. After 3 wks, the Δ[HHb+Mb]/V̇O2p overshoot was eliminated only in the training groups, so that τ'[HHb+Mb] was not different to τV̇O2p in MICT and HIIT. The enhanced V̇O2 kinetics response consequent to both MICT and HIIT in T2D was likely attributed to a training-induced improvement in matching of O2 delivery to utilization.

scholarly journals Oxygen Uptake Kinetics During Arm Cranking Within The Moderate Intensity Domain

2009 ◽  
Vol 41 ◽  
pp. 116
Author(s):  
Surendran Sabapathy ◽  
Norman R. Morris ◽  
Donald A. Schneider ◽  
Donald H. Paterson
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Uptake Kinetics ◽  
Uptake Kinetics ◽  
Moderate Intensity ◽  
Arm Cranking

scholarly journals Comparison of femoral blood gases and muscle near-infrared spectroscopy at exercise onset in humans

1999 ◽  
Vol 86 (2) ◽  
pp. 687-693 ◽  
Author(s):  
Maureen J. MacDonald ◽  
Mark A. Tarnopolsky ◽  
Howard J. Green ◽  
Richard L. Hughson
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Femoral Vein ◽  
Blood Gases ◽  
Moderate Intensity ◽  
Reliable Estimate ◽  
Vastus Lateralis Muscle ◽  
Exercise Onset

We hypothesized that near-infrared spectroscopy (NIRS) measures of hemoglobin and/or myoglobin O2 saturation (IR-So 2) in the vascular bed of exercising muscle would parallel changes in femoral venous O2 saturation (S[Formula: see text]) at the onset of leg-kicking exercise in humans. Six healthy subjects performed transitions from rest to 48 ± 3 (SE)-W two-legged kicking exercise while breathing 14, 21, or 70% inspired O2. IR-So 2 was measured over the vastus lateralis muscle continuously during all tests, and femoral venous and radial artery blood samples were drawn simultaneously during rest and during 5 min of exercise. In all gas-breathing conditions, there was a rapid decrease in both IR-So 2 and SfvO2 at the onset of moderate-intensity leg-kicking exercise. Although SfvO2 remained at low levels throughout exercise, IR-So 2increased significantly after the first minute of exercise in both normoxia and hyperoxia. Contrary to the hypothesis, these data show that NIRS does not provide a reliable estimate of hemoglobin and/or O2 saturation as reflected by direct femoral vein sampling.

scholarly journals Chronic Adaptations On The Oxygen Uptake Kinetics In Trained Older Adults With Coronary Artery Disease

2019 ◽  
Vol 51 (Supplement) ◽  
pp. 257
Author(s):  
Rita Pinto ◽  
Joana Reis ◽  
Vitor Angarten ◽  
Madalena Lemos Pires ◽  
Mariana Borges ◽  
...  
Keyword(s):  
Older Adults ◽  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Oxygen Uptake ◽  
Oxygen Uptake Kinetics ◽  
Uptake Kinetics ◽  
Artery Disease

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.

scholarly journals Blood flow occlusion-related O2 extraction “reserve” is present in different muscles of the quadriceps but greater in deeper regions after ramp-incremental test

2018 ◽  
Vol 125 (2) ◽  
pp. 313-319 ◽  
Author(s):  
Danilo Iannetta ◽  
Dai Okushima ◽  
Erin Calaine Inglis ◽  
Narihiko Kondo ◽  
Juan M Murias ◽  
...  
Keyword(s):  
Blood Flow ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Incremental Exercise ◽  
Vastus Lateralis Muscle ◽  
Incremental Test ◽  
Time Resolved ◽  
Blood Flow Occlusion ◽  
Flow Occlusion

It was recently demonstrated that an O2 extraction reserve, as assessed by the near-infrared spectroscopy (NIRS)-derived deoxygenation signal ([HHb]), exists in the superficial region of vastus lateralis (VL) muscle during an occlusion performed at the end of a ramp-incremental test. However, it is unknown whether this reserve is present and/or different in magnitude in other portions and depths of the quadriceps muscles. We tested the hypothesis that an O2 extraction reserve would exist in other regions of this muscle but is greater in deep compared with more superficial portions. Superficial (VL-s) and deep VL (VL-d) as well as superficial rectus femoris (RF-s) were monitored by a combination of low- and high-power time-resolved (TRS) NIRS. During the occlusion immediately post-ramp-incremental test there was a significant overshoot in the [HHb] signal ( P < 0.05). However, the magnitude of this increase was greater in VL-d (93.2 ± 42.9%) compared with VL-s (55.0 ± 19.6%) and RF-s (47.8 ± 14.0%) ( P < 0.05). The present study demonstrated that an O2 extraction reserve exists in different pools of active muscle fibers of the quadriceps at the end of a ramp exercise to exhaustion. The greater magnitude in the reserve observed in the deeper portion of VL, however, suggests that this portion of muscle may present a greater surplus of oxygenated blood, which is likely due to a greater population of slow-twitch fibers. These findings add to the notion that the plateau in the [HHb] signal toward the end of a ramp-incremental exercise does not indicate the upper limit of O2 extraction. NEW & NOTEWORTHY Different portions of the quadriceps muscles exhibited an untapped O2 extraction reserve during a blood flow occlusion performed at the end of a ramp-incremental exercise. In the deeper portion of the vastus lateralis muscle, this reserve was greater compared with superficial vastus lateralis and rectus femoris. These data suggest that the O2 extraction reserve may be dependent on the vascular and/or oxidative capacities of the muscles.

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