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 Time course of changes in V̇O2peak and O2 extraction during ramp cycle exercise following 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 ◽  
Moderate Intensity ◽  
Control Group ◽  
Vastus Lateralis Muscle ◽  
Linear Segment ◽  
Maximal Heart Rate ◽  
Low Volume

In the present study we assessed the time course of adaptations in peak oxygen uptake (V̇O2peak) and muscle fractional oxygen (O2) extraction (using near-infrared spectroscopy) following 12 weeks of low-volume high-intensity interval training (HIIT) vs. moderate-intensity continuous endurance training (MICT) in adults with uncomplicated type 2 diabetes (T2D). Participants with T2D were randomly assigned to MICT (n = 12, 50 min of moderate-intensity cycling), HIIT (n = 9, 10 x 1 min at ~90% maximal heart rate) or to a non-exercising control group (n = 9). Exercising groups trained 3 times per week and measurements were taken every 3 weeks. The rate of muscle deoxygenation (i.e. deoxygenated haemoglobin and myoglobin concentration, Δ[HHb+Mb]) profiles of the vastus lateralis muscle were normalised to 100% of the response, plotted against % power output (PO) and fitted with a double linear regression model. V̇O2peak increased (P<0.05) by week 3 of MICT (+17%) and HIIT (+8%), with no further significant changes thereafter. Total increases in V̇O2peak posttraining (P<0.05) were 27% and 14% respectively. The %∆[HHb+Mb] vs %PO slope of the first linear segment (slope1) was reduced (P<0.05) beyond 3 weeks of HIIT and MICT with no further significant changes thereafter. No changes in V̇O2peak or slope1 were observed in the control group. Low-volume HIIT and MICT induced improvements in V̇O2peak following a similar time course and these improvements were likely, at least in part, due to an improved microvascular O2 delivery.

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.

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.

Effect of age on O2 uptake kinetics and the adaptation of muscle deoxygenation at the onset of moderate-intensity cycling exercise

2004 ◽  
Vol 97 (1) ◽  
pp. 165-172 ◽  
Author(s):  
Darren S. DeLorey ◽  
John M. Kowalchuk ◽  
Donald H. Paterson
Keyword(s):  
Time Delay ◽  
Time Constant ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Muscle Blood Flow ◽  
Moderate Intensity ◽  
Vastus Lateralis Muscle ◽  
Phase 2 ◽  
Cycling Exercise ◽  
Muscle Deoxygenation

Phase 2 pulmonary O2 uptake (V̇o2p) kinetics are slowed with aging. To examine the effect of aging on the adaptation of V̇o2p and deoxygenation of the vastus lateralis muscle at the onset of moderate-intensity constant-load cycling exercise, young (Y) ( n = 6; 25 ± 3 yr) and older (O) ( n = 6; 68 ± 3 yr) adults performed repeated transitions from 20 W to work rates corresponding to moderate-intensity (80% estimated lactate threshold) exercise. Breath-by-breath V̇o2p was measured by mass spectrometer and volume turbine. Deoxy (HHb)-, oxy-, and total Hb and/or myoglobin were determined by near-infrared spectroscopy (Hamamatsu NIRO-300). V̇o2p data were filtered, interpolated to 1 s, and averaged to 5-s bins. HHb data were filtered and averaged to 5-s bins. V̇o2p data were fit with a monoexponential model for phase 2, and HHb data were analyzed to determine the time delay from exercise onset to the start of an increase in HHb and thereafter were fit with a single-component exponential model. The phase 2 time constant for V̇o2p was slower ( P < 0.01) in O (Y: 26 ± 7 s; O: 42 ± 9 s), whereas the delay before an increase in HHb (Y: 12 ± 2 s; O: 11 ± 1 s) and the time constant for HHb after the time delay (Y: 13 ± 10 s; O: 9 ± 3 s) were similar in Y and O. However, the increase in HHb for a given increase in V̇o2p (Y: 7 ± 2 μM·l−1·min−1; O: 13 ± 4 μM·l−1·min−1) was greater ( P < 0.01) in O compared with Y. The slower V̇o2p kinetics in O compared with Y adults was accompanied by a slower increase of local muscle blood flow and O2 delivery discerned from a faster and greater muscle deoxygenation relative to V̇o2p in O.

scholarly journals Influence of priming exercise on oxygen uptake and muscle deoxygenation kinetics during moderate-intensity cycling in type 2 diabetes

2019 ◽  
Vol 127 (4) ◽  
pp. 1140-1149 ◽  
Author(s):  
Joel Rocha ◽  
Norita Gildea ◽  
Donal O’Shea ◽  
Simon Green ◽  
Mikel Egaña
Keyword(s):  
Type 2 Diabetes ◽  
Infrared Spectroscopy ◽  
Oxygen Uptake ◽  
Near Infrared ◽  
Moderate Intensity ◽  
Middle Aged ◽  
Pulmonary Oxygen Uptake ◽  
Muscle Deoxygenation ◽  
Priming Exercise

The pulmonary oxygen uptake (V̇o2) kinetics during the transition to moderate-intensity exercise is slowed in individuals with type 2 diabetes (T2D), at least in part because of limitations in O2 delivery. The present study tested the hypothesis that a prior heavy-intensity warm-up or “priming” exercise (PE) bout would accelerate V̇o2 kinetics in T2D, because of a better matching of O2 delivery to utilization. Twelve middle-aged individuals with T2D and 12 healthy controls (ND) completed moderate-intensity constant-load cycling bouts either without (Mod A) or with (Mod B) prior PE. The rates of muscle deoxygenation (i.e., deoxygenated hemoglobin and myoglobin concentration, [HHb+Mb]) and oxygenation (i.e., tissue oxygenation index) were continuously 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]-to-ΔV̇o2 ratio. Both groups demonstrated an accelerated V̇O2 kinetics response during Mod B compared with Mod A (T2D, 32 ± 9 vs. 42 ± 12 s; ND, 28 ± 9 vs. 34 ± 8 s; means ± SD) and an elevated muscle oxygenation throughout Mod B, whereas the [HHb+Mb] amplitude was greater during Mod B only in individuals with T2D. The [HHb+Mb] kinetics remained unchanged in both groups. In T2D, Mod B was associated with a decrease in the “overshoot” relative to steady state in the Δ[HHb+Mb]-to-ΔV̇o2 ratio (1.17 ± 0.17 vs. 1.05 ± 0.15), whereas no overshoot was observed in the control group before (1.04 ± 0.12) or after (1.01 ± 0.12) PE. Our findings support a favorable priming-induced acceleration of the V̇o2 kinetics response in middle-aged individuals with uncomplicated T2D attributed to an enhanced matching of microvascular O2 delivery to utilization. NEW & NOTEWORTHY Heavy-intensity “priming” exercise (PE) elicited faster pulmonary oxygen uptake (V̇o2) kinetics during moderate-intensity cycling exercise in middle-aged individuals with type 2 diabetes (T2D). This was accompanied by greater near-infrared spectroscopy-derived muscle deoxygenation (i.e., deoxygenated hemoglobin and myoglobin concentration, [HHb+Mb]) responses and a reduced Δ[HHb+Mb]-to-ΔV̇o2 ratio. This suggests that the PE-induced acceleration in oxidative metabolism in T2D is a result of greater O2 extraction and better matching between O2 delivery and utilization.

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.

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