Validity and Reliability of the Cosmed K2 to Measure Oxygen Uptake

1993 ◽  
Vol 18 (2) ◽  
pp. 197-206 ◽  
Author(s):  
F. Lothian ◽  
M. R. Farrally ◽  
C. Mahoney
Keyword(s):  
Oxygen Uptake ◽  
Key Words ◽  
Female Subject ◽  
Peak Oxygen Uptake ◽  
Variation Coefficient ◽  
Validity And Reliability ◽  
System A ◽  
On Line ◽  
The Difference ◽  
Line Oxygen

The validity and reliability of the Cosmed K2 was tested in comparison with a Quinton on-line oxygen analysing system. A female subject was monitored on a treadmill using a progressive protocol and was measured on three occasions with each system. It was found at low workloads that the Cosmed K2 and the Quinton gave the same measure of oxygen uptake; at higher workloads the Cosmed K2 gave lower values, and at peak oxygen uptake the Cosmed K2 measured 22.2% less than the Quinton. The difference in the measurement of [Formula: see text] at peak oxygen uptake was 13%. The Cosmed K2's measurement of [Formula: see text] showed a greater variability between trials (variation coefficient 3.0-11.4%) than the Quinton (variation coefficient 1.1-3.9%). Key words: Cosmed K2, validity, telemetry

Kinetics of oxygen uptake at the onset of exercise near or above peak oxygen uptake

2000 ◽  
Vol 88 (5) ◽  
pp. 1812-1819 ◽  
Author(s):  
R. L. Hughson ◽  
D. D. O'Leary ◽  
A. C. Betik ◽  
H. Hebestreit
Keyword(s):  
Oxygen Uptake ◽  
Cardiovascular System ◽  
Time Constant ◽  
Exponential Model ◽  
Peak Oxygen Uptake ◽  
Phase 2 ◽  
Heavy Exercise ◽  
The Difference ◽  
Kinetics Of ◽  
Model Phase

We tested the hypothesis that kinetics of O2 uptake (V˙o 2) measured in the transition to exercise near or above peakV˙o 2(V˙o 2 peak) would be slower than those for subventilatory threshold exercise. Eight healthy young men exercised at ∼57, ∼96, and ∼125%V˙o 2 peak. Data were fit by a two- or three-component exponential model and with a semilogarithmic transformation that tested the difference between required V˙o 2 and measuredV˙o 2. With the exponential model, phase 2 kinetics appeared to be faster at 125% V˙o 2 peak[time constant (τ2) = 16.3 ± 8.8 (SE) s] than at 57%V˙o 2 peak(τ2 = 29.4 ± 4.0 s) but were not different from that at 96%V˙o 2 peakexercise (τ2 = 22.1 ± 2.1 s).V˙o 2 at the completion of phase 2 was 77 and 80%V˙o 2 peak in tests predicted to require 96 and 125%V˙o 2 peak. WhenV˙o 2 kinetics were calculated with the semilogarithmic model, the estimated τ2 at 96%V˙o 2 peak (49.7 ± 5.1 s) and 125%V˙o 2 peak (40.2 ± 5.1 s) were slower than with the exponential model. These results are consistent with our hypothesis and with a model in which the cardiovascular system is compromised during very heavy exercise.

High density culture of mammalian cells with dynamic perfusion based on on-line oxygen uptake rate measurements

1994 ◽  
Vol 14 (3) ◽  
pp. 183-190 ◽  
Author(s):  
Yun-Seung Kyung ◽  
Madhusudan V. Peshwa ◽  
David M. Gryte ◽  
Wei-Shou Hu
Keyword(s):  
Oxygen Uptake ◽  
Uptake Rate ◽  
Mammalian Cells ◽  
Oxygen Uptake Rate ◽  
High Density ◽  
High Density Culture ◽  
On Line ◽  
Line Oxygen

New Control Parameters and Measurement Techniques for the Activated Sludge Process

1993 ◽  
Vol 27 (5-6) ◽  
pp. 287-295 ◽  
Author(s):  
M. Pelkonen ◽  
R. Tenno
Keyword(s):  
Oxygen Uptake ◽  
Production Rate ◽  
Uptake Rate ◽  
Oxygen Uptake Rate ◽  
Measurement Techniques ◽  
Co2 Production ◽  
Carbon Oxidation ◽  
Nitrification Process ◽  
On Line ◽  
Line Oxygen

An on-line oxygen uptake and CO2-production rate measurement system was used to analyse the biomass activity. CO2-production rate corresponded well with oxygen uptake rate in the carbon oxidation process. In the nitrification process the ratio CO2-prod./O2-consumed (rq) had a larger variation, but CO2-production had a good correlation with utilized COD; variation of the rq-value indicate differences in the auto-/heterotrop-hic oxidation balarice. From this basis the oxygen uptake rate for carbon oxidation and nitrification can be separated. The comparison with two biomass determination methods based on ATP-analysis shows that for heterotrophic biomass the methods indicate clearly different changes of ATP, for nitrification process the results were more compatible. By combining the biomass and on-line measurements with biomass growth model based on IAWPRC-model equations reasonably good estimates were obtained. Best fit of model was in the nitrification process; by using VSS as the measure of biomass the fit was poor. The differences in the ATP-measurement results affect also the model coefficients.

scholarly journals Noninvasive assessment of muscle temperature during rest, exercise, and postexercise recovery in different environments

2015 ◽  
Vol 118 (10) ◽  
pp. 1310-1320 ◽  
Author(s):  
Andreas D. Flouris ◽  
Paul Webb ◽  
Glen P. Kenny
Keyword(s):  
Relative Humidity ◽  
Oxygen Uptake ◽  
Vastus Lateralis ◽  
Peak Oxygen Uptake ◽  
Muscle Temperature ◽  
Triceps Brachii ◽  
Cycling Exercise ◽  
Small Effect Size ◽  
The Difference ◽  
Postexercise Recovery

We introduced noninvasive and accurate techniques to estimate muscle temperature (Tm) of vastus lateralis (VL), triceps brachii (TB), and trapezius (TRAP) during rest, exercise, and postexercise recovery using the insulation disk (iDISK) technique. Thirty-six volunteers (24 men, 12 women; 73.0 ± 12.2 kg; 1.75 ± 0.07 m; 24.4 ± 5.5 yr; 49.2 ± 6.8 ml·kg−1·min−1 peak oxygen uptake) underwent periods of rest, cycling exercise at 40% of peak oxygen uptake, and postexercise recovery in three environments: Normal (24°C, 56% relative humidity), Hot-Humid (30°C, 60% relative humidity), and Hot-Dry (40°C, 24% relative humidity). Participants were randomly allocated into the “model” and the “validation” groups. Results in the model group demonstrated that Tm (VL: 36.65 ± 1.27°C; TB: 35.76 ± 1.73°C; TRAP: 36.53 ± 0.96°C) was increased compared with iDISK (VL: 35.67 ± 1.71°C; TB: 34.77 ± 2.27°C; TRAP: 35.98 ± 1.34°C) across all environments ( P < 0.001). Stepwise regression analysis generated models that accurately predicted Tm (predTm) of VL ( R2 = 0.73-0.91), TB ( R2 = 0.85–0.93), and TRAP ( R2 = 0.84–0.86) using iDISK and the difference between the current iDISK temperature and that recorded between 1 and 4 min before. Cross-validation analyses in the validation group demonstrated small differences ( P < 0.05) of no physiological significance, small effect size of the differences, and strong associations ( r = 0.85–0.97; P < 0.001) between Tm and predTm. Moreover, narrow 95% limits of agreement and low percent coefficient of variation were observed between Tm and predTm. It is concluded that the developed noninvasive, practical, and inexpensive techniques provide accurate estimations of VL, TB, and TRAP Tm during rest, cycling exercise, and postexercise recovery.

scholarly journals Lung function and peak oxygen uptake in chronic obstructive pulmonary disease phenotypes with and without emphysema

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0252386
Author(s):  
Øystein Rasch-Halvorsen ◽  
Erlend Hassel ◽  
Ben M. Brumpton ◽  
Haldor Jenssen ◽  
Martijn A. Spruit ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Oxygen Uptake ◽  
Pulmonary Disease ◽  
Peak Oxygen Uptake ◽  
Chronic Obstructive ◽  
P Value ◽  
Linear Regression Models ◽  
Obstructive Pulmonary Disease ◽  
The Difference ◽  
Unit Reduction

Previous studies of associations of forced expiratory lung volume in one second (FEV1) with peak oxygen uptake (VO2peak) in chronic obstructive pulmonary disease (COPD) have not taken sex, age and height related variance of dynamic lung volumes into account. Nor have such demographic spread of spirometric measures been considered in studies comparing VO2peak between COPD phenotypes characterized by degree of emphysema. We aimed to assess the association of FEV1Z-score with VO2peak in COPD (n = 186) and investigate whether this association differs between emphysema (E-COPD) and non-emphysema (NE-COPD) phenotypes. Corresponding assessments using standardized percent predicted FEV1 (ppFEV1) were performed for comparison. Additionally, phenotype related differences in VO2peak were compared using FEV1Z-score and ppFEV1 as alternative expressions of FEV1. E-COPD and NE-COPD were defined by transfer factor of the lung for carbon monoxide below and above lower limits of normal (LLN), respectively. The associations were assessed in linear regression models. One unit reduction in FEV1Z-score was associated with 1.9 (95% CI 1.4, 2.5) ml/kg/min lower VO2peak. In stratified analyses, corresponding estimates were 2.2 (95% CI 1.4, 2.9) and 1.2 (95% CI 0.2, 2.2) ml/kg/min lower VO2peak in E-COPD and NE-COPD, respectively. The association did not differ statistically by COPD phenotype (p-value for interaction = 0.153). Similar estimates were obtained in analyses using standardized ppFEV1. Compared to NE-COPD, VO2peak was 2.2 (95% CI 0.8, 3.6) and 2.1 (95% CI 0.8, 3.5) ml/kg/min lower in E-COPD when adjusted for FEV1Z-score and ppFEV1, respectively. In COPD, FEV1Z-score is positively associated with VO2peak. This association was stronger in E-COPD but did not differ statistically by phenotype. Both the association of FEV1 with VO2peak and the difference in VO2peak comparing COPD phenotypes seems independent of sex, age and height related variance in FEV1. Mechanisms leading to reduction in FEV1 may contribute to lower VO2peak in E-COPD.

Effect of acute nitrate ingestion on V̇O2 response at different exercise intensity domains

2017 ◽  
Vol 42 (11) ◽  
pp. 1127-1134 ◽  
Author(s):  
Thaysa Ghiarone ◽  
Thays Ataide-Silva ◽  
Romulo Bertuzzi ◽  
Glenn Kevin McConell ◽  
Adriano Eduardo Lima-Silva
Keyword(s):  
Oxygen Uptake ◽  
Exercise Intensity ◽  
Slow Component ◽  
Peak Oxygen Uptake ◽  
Time To Exhaustion ◽  
Severe Exercise ◽  
Nitrate Supplementation ◽  
The Difference ◽  
Response To Exercise ◽  
Gas Exchange Threshold

While nitrate supplementation influences oxygen uptake (V̇O2) response to exercise, this effect may be intensity dependent. The purpose of this study was to investigate the effect of acute nitrate supplementation on V̇O2 response during different exercise intensity domains in humans. Eleven men ingested 10 mg·kg−1 body mass (8.76 ± 1.35 mmol) of sodium nitrate or sodium chloride (placebo) 2.5 h before cycling at moderate (90% of gas exchange threshold; GET), heavy (GET + 40% of the difference between GET and peak oxygen uptake (V̇O2peak), Δ 40) or severe (GET + 80% of the difference between GET and V̇O2peak, Δ 80) exercise intensities. Volunteers performed exercise for 10 min (moderate), 15 min (heavy) or until exhaustion (severe). Acute nitrate supplementation had no effect on any V̇O2 response parameters during moderate and severe exercise intensities. However, the V̇O2 slow amplitude (nitrate: 0.93 ± 0.36 L·min−1 vs. placebo: 1.13 ± 0.59 L·min−1, p = 0.04) and V̇O2 slow gain (nitrate: 5.81 ± 2.37 mL·min–1·W−1 vs. placebo: 7.09 ± 3.67 mL·min–1·W−1, p = 0.04) were significantly lower in nitrate than in placebo during the heavy exercise intensity. There was no effect of nitrate on plasma lactate during any exercise intensity (p > 0.05). Time to exhaustion during the severe exercise intensity was also not affected by nitrate (p > 0.05). In conclusion, acute nitrate supplementation reduced the slow component of V̇O2 only when performing heavy-intensity exercise, which might indicate an intensity-dependent effect of nitrate on V̇O2 response.

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