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.

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 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 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 Cocoa-flavanols enhance moderate-intensity pulmonary V̇O2 kinetics but not exercise tolerance in sedentary middle-aged adults: A randomised controlled trial

2020 ◽  
Author(s):  
Daniel Sadler ◽  
Richard Draijer ◽  
Claire E. Stewart ◽  
Helen Jones ◽  
Simon Marwood ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Exercise Tolerance ◽  
Oxygen Uptake Kinetics ◽  
Uptake Kinetics ◽  
Moderate Intensity ◽  
Moderate Activity ◽  
Middle Aged ◽  
Severe Intensity ◽  
Middle Aged Adults ◽  
Cocoa Flavanols

Abstract Background: Cocoa flavanols (CF) may exert health benefits through their potent vasodilatory effects which are perpetuated by elevations in nitric oxide (NO) bioavailability. These vasodilatory effects may contribute to improved delivery of blood and oxygen to exercising muscle.Objective: Therefore, the objective of this study was to examine how CF supplementation impacts pulmonary oxygen uptake (V̇O2) kinetics and exercise tolerance in sedentary middle-aged adults.Methods: We employed a double-blind cross-over, placebo-controlled design whereby 17 participants (11 male, 6 female; mean±SD, 45±6 years) randomly received either 7 days of daily CF (400 mg) or placebo (PL) supplementation. On day 7, participants completed a series of ‘step’ moderate- and severe-intensity exercise tests for the determination of oxygen uptake kinetics.Results: During moderate-intensity exercise, the time constant of the fundamental phase of V̇O2 kinetics (τV̇O2) was decreased by 15% in CF as compared to PL (mean±SD; PL: 40±12 vs. CF: 34±9 s, P=0.019), with no differences in the amplitude of V̇O2 (AV̇O2; PL: 0.77±0.32 vs. CF: 0.79±0.34 l min−1, P=0.263). However, during severe-intensity exercise, τV̇O2,the amplitude of the slow component (SCV̇O2) and exercise tolerance (PL: 435±58 vs. CF: 424±47 s, P=0.480) were unchanged between conditions.Conclusions: Our data show that acute CF supplementation enhanced oxygen uptake kinetics during moderate-, but not severe-intensity exercise in middle-aged participants. These novel effects of CFs, in this demographic, may contribute to improved tolerance of moderate-activity physical activities, which appear commonly present in daily life.Registered under ClinicalTrials.gov Identifier no. NCT04370353

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

Morning–evening differences in response to exhaustive severe-intensity exercise

2014 ◽  
Vol 39 (2) ◽  
pp. 248-254 ◽  
Author(s):  
David W. Hill
Keyword(s):  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Anaerobic Capacity ◽  
Oxygen Uptake Kinetics ◽  
Sport Performance ◽  
Time Of Day ◽  
Uptake Kinetics ◽  
Oxygen Deficit ◽  
Time To Exhaustion ◽  
Severe Intensity

The aim was to investigate the effect of time of day on 4 variables that are related to sport performance. Twenty healthy young men (mean ± SD: 22 ± 3 years, 1.78 ± 0.08 m, 72.0 ± 7.0 kg) performed exhaustive severe-intensity cycle ergometer tests at 278 ± 35 W (3.8 ± 0.4 W·kg–1) in the morning (between 0630 h and 0930 h) and in the evening (between 1700 h and 2000 h). Despite that gross efficiency was lower in the evening (estimated oxygen demand was 6% higher, P < 0.05), time to exhaustion was 20% greater (P < 0.01) in the evening (329 ± 35 s) than in the morning (275 ± 29 s). Performance in the evening was associated with a 4% higher (P < 0.01) maximal oxygen uptake (54 ± 7 mL·kg–1·min–1 vs. 52 ± 6 mL·kg–1·min–1, for the evening and the morning, respectively) and a 7% higher (P < 0.01) anaerobic capacity (as reflected by maximal accumulated oxygen deficit: 75 ± 9 mL·kg–1 vs. 70 ± 7 mL·kg–1, for the evening and the morning, respectively). In addition, oxygen uptake kinetics was faster in the evening, which resulted in slower utilization of the anaerobic reserves. It is concluded that modest morning–evening differences in maximal oxygen uptake, anaerobic capacity, and oxygen uptake kinetics conflate to produce a markedly longer performance in the evening than in the morning. Time of day must be considered for exercise testing and perhaps for exercise training.

Oxygen uptake kinetics in children and adults after the onset of moderate-intensity exercise

2002 ◽  
Vol 20 (4) ◽  
pp. 319-326 ◽  
Author(s):  
Samantha G. Fawkner ◽  
Neil Armstrong ◽  
Christopher R. Potter ◽  
Joanne R. Welsman
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Uptake Kinetics ◽  
Uptake Kinetics ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise
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