V˙o 2 and heart rate kinetics in cycling: transitions from an elevated baseline

2001 ◽  
Vol 90 (6) ◽  
pp. 2081-2087 ◽  
Author(s):  
S. E. Bearden ◽  
R. J. Moffatt
Keyword(s):  
Heart Rate ◽  
Base Excess ◽  
Slow Component ◽  
Lactate Concentration ◽  
Fast Component ◽  
Square Wave ◽  
Mean Response Time ◽  
Rate Kinetics ◽  
Component Amplitude ◽  
Heart Rate Kinetics

The purpose of this study was to examine oxygen consumption (V˙o 2) and heart rate kinetics during moderate and repeated bouts of heavy square-wave cycling from an exercising baseline. Eight healthy, male volunteers performed square-wave bouts of leg ergometry above and below the gas exchange threshold separated by recovery cycling at 35%V˙o 2 peak.V˙o 2 and heart rate kinetics were modeled, after removal of phase I data by use of a biphasic on-kinetics and monoexponential off-kinetics model. Fingertip capillary blood was sampled 45 s before each transition for base excess, HCO[Formula: see text] and lactate concentration, and pH. Base excess and HCO[Formula: see text] concentration were significantly lower, whereas lactate concentration and pH were not different before the second bout. The results confirm earlier reports of a smaller mean response time in the second heavy bout. This was the result of a significantly greater fast-component amplitude and smaller slow-component amplitude with invariant fast-component time constant. A role for local oxygen delivery limitation in heavy exercise transitions with unloaded but not moderate baselines is presented.

scholarly journals Effects of hypoxic hypoxia on O2 uptake and heart rate kinetics during heavy exercise

1996 ◽  
Vol 81 (6) ◽  
pp. 2500-2508 ◽  
Author(s):  
Marielle Engelen ◽  
Janos Porszasz ◽  
Marshall Riley ◽  
Karlman Wasserman ◽  
Kazuhira Maehara ◽  
...  
Keyword(s):  
Heart Rate ◽  
Time Constant ◽  
Slow Component ◽  
Hypoxic Hypoxia ◽  
Baseline Heart Rate ◽  
Heavy Exercise ◽  
Rate Kinetics ◽  
Lactic Acidosis Threshold ◽  
Kinetics Of ◽  
Heart Rate Kinetics

Engelen, Marielle, Janos Porszasz, Marshall Riley, Karlman Wasserman, Kazuhira Maehara, and Thomas J. Barstow. Effects of hypoxic hypoxia on O2 uptake and heart rate kinetics during heavy exercise. J. Appl. Physiol. 81(6): 2500–2508, 1996.—It is unclear whether hypoxia alters the kinetics of O2 uptake (V˙o 2) during heavy exercise [above the lactic acidosis threshold (LAT)] and how these alterations might be linked to the rise in blood lactate. Eight healthy volunteers performed transitions from unloaded cycling to the same absolute heavy work rate for 8 min while breathing one of three inspired O2 concentrations: 21% (room air), 15% (mild hypoxia), and 12% (moderate hypoxia). Breathing 12% O2 slowed the time constant but did not affect the amplitude of the primary rise inV˙o 2 (period of first 2–3 min of exercise) and had no significant effect on either the time constant or the amplitude of the slowV˙o 2 component (beginning 2–3 min into exercise). Baseline heart rate was elevated in proportion to the severity of the hypoxia, but the amplitude and kinetics of increase during exercise and in recovery were unaffected by level of inspired O2. We conclude that the predominant effect of hypoxia during heavy exercise is on the early energetics as a slowed time constant forV˙o 2 and an additional anaerobic contribution. However, the sum total of the processes representing the slow component ofV˙o 2 is unaffected.

Effect of heliox on heart rate kinetics and dynamic hyperinflation during high-intensity exercise in COPD

2010 ◽  
Vol 111 (2) ◽  
pp. 225-234 ◽  
Author(s):  
Pierantonio Laveneziana ◽  
Gabriele Valli ◽  
Paolo Onorati ◽  
Patrizia Paoletti ◽  
Alessandro Maria Ferrazza ◽  
...  
Keyword(s):  
Heart Rate ◽  
High Intensity ◽  
High Intensity Exercise ◽  
Dynamic Hyperinflation ◽  
Rate Kinetics ◽  
Heart Rate Kinetics

Muscle Metaboreflex Modulation of Heart Rate Kinetics During the Transition to Low-Moderate and High-Moderate Exercise Intensities

2017 ◽  
Vol 49 (5S) ◽  
pp. 725
Author(s):  
Natasha G. Boyes ◽  
Josie T.J. Fries ◽  
Stephanie Fusnik ◽  
Paul J. Fadel ◽  
Corey R. Tomczak
Keyword(s):  
Heart Rate ◽  
Moderate Exercise ◽  
Muscle Metaboreflex ◽  
Rate Kinetics ◽  
Heart Rate Kinetics

Bronchodilator effect on ventilatory, pulmonary gas exchange, and heart rate kinetics during high-intensity exercise in COPD

2009 ◽  
Vol 107 (6) ◽  
pp. 633-643 ◽  
Author(s):  
Pierantonio Laveneziana ◽  
Paolo Palange ◽  
Josuel Ora ◽  
Dario Martolini ◽  
Denis E. O’Donnell
Keyword(s):  
Heart Rate ◽  
Gas Exchange ◽  
High Intensity ◽  
Pulmonary Gas Exchange ◽  
High Intensity Exercise ◽  
Bronchodilator Effect ◽  
Rate Kinetics ◽  
Heart Rate Kinetics

Abnormal oxygen uptake kinetic responses in women with type II diabetes mellitus

1998 ◽  
Vol 85 (1) ◽  
pp. 310-317 ◽  
Author(s):  
Judith G. Regensteiner ◽  
Timothy A. Bauer ◽  
Jane E. B. Reusch ◽  
Suzanne L. Brandenburg ◽  
Jeffrey M. Sippel ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Heart Rate ◽  
Oxygen Consumption ◽  
Type Ii Diabetes ◽  
Lactate Threshold ◽  
Type Ii Diabetes Mellitus ◽  
Constant Load ◽  
Type Ii ◽  
Rate Kinetics ◽  
Heart Rate Kinetics

Persons with type II diabetes mellitus (DM), even without cardiovascular complications have a decreased maximal oxygen consumption (V˙o2 max) and submaximal oxygen consumption (V˙o2) during graded exercise compared with healthy controls. We evaluated the hypothesis that change in the rate ofV˙o2in response to the onset of constant-load exercise (measured byV˙o2-uptake kinetics) was slowed in persons with type II DM. Ten premenopausal women with uncomplicated type II DM, 10 overweight, nondiabetic women, and 10 lean, nondiabetic women had aV˙o2 maxtest. On two separate occasions, subjects performed 7-min bouts of constant-load bicycle exercise at workloads below and above the lactate threshold to enable measurements of V˙o2kinetics and heart rate kinetics (measuring rate of heart rate rise).V˙o2 maxwas reduced in subjects with type II DM compared with both lean and overweight controls ( P < 0.05). Subjects with type II DM had slowerV˙o2and heart rate kinetics than did controls at constant workloads below the lactate threshold. The data suggest a notable abnormality in the cardiopulmonary response at the onset of exercise in people with type II DM. The findings may reflect impaired cardiac responses to exercise, although an additional defect in skeletal muscle oxygen diffusion or mitochondrial oxygen utilization is also possible.

scholarly journals Modelling Heart Rate Kinetics

PLoS ONE ◽  
2015 ◽  
Vol 10 (4) ◽  
pp. e0118263 ◽  
Author(s):  
Maria S. Zakynthinaki
Keyword(s):  
Heart Rate ◽  
Rate Kinetics ◽  
Heart Rate Kinetics

Heart Rate Variability Threshold Determined from Heart Rate Kinetics and Perceived Exertion in Overweight Young

2015 ◽  
Vol 47 ◽  
pp. 909
Author(s):  
Gisela Arsa ◽  
André R.L. Dias ◽  
Kamila M. Santos ◽  
Fabiula Isoton Novelli ◽  
Katrice A. Souza ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Perceived Exertion ◽  
Rate Kinetics ◽  
Heart Rate Kinetics
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