Limits...
Comparison of the Cosmed K4b(2) portable metabolic system in measuring steady-state walking energy expenditure.

Schrack JA, Simonsick EM, Ferrucci L - PLoS ONE (2010)

Bottom Line: Average oxygen consumption (VO2) and carbon dioxide production (VCO2) from each walk were compared.Comparison of the average values obtained using the Cosmed K4b(2) and Medgraphics systems using paired t-tests indicate no significant difference for VO2 (ml/kg/min) overall (p = 0.25), or when stratified by sex (p = 0.21 women, p = 0.69 men).Results were not significantly different for VO(2) (ml/min) or VCO2) (ml/min) within the study population (p = 0.16 and p = 0.08, respectively), or when stratified by sex (VO(2): p = 0.51 women, p = 0.16 men; VCO2: p = .11 women, p = 0.53 men).

View Article: PubMed Central - PubMed

Affiliation: Longitudinal Studies Section, Clinical Research Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America. schrackja@mail.nih.gov

ABSTRACT

Background and aims: Recent introduction of the Cosmed K4b(2) portable metabolic analyzer allows measurement of oxygen consumption outside of a laboratory setting in more typical clinical or household environments and thus may be used to obtain information on the metabolic costs of specific daily life activities. The purpose of this study was to assess the accuracy of the Cosmed K4b(2) portable metabolic analyzer against a traditional, stationary gas exchange system (the Medgraphics D-Series) during steady-state, submaximal walking exercise.

Methods: Nineteen men and women (9 women, 10 men) with an average age of 39.8 years (+/-13.8) completed two 400 meter walk tests using the two systems at a constant, self-selected pace on a treadmill. Average oxygen consumption (VO2) and carbon dioxide production (VCO2) from each walk were compared.

Results: Intraclass Correlation Coefficient (ICC) and Pearson correlation coefficients between the two systems for weight indexed VO2 (ml/kg/min), total VO2 (ml/min), and VCO2 (ml/min) ranged from 0.93 to 0.97. Comparison of the average values obtained using the Cosmed K4b(2) and Medgraphics systems using paired t-tests indicate no significant difference for VO2 (ml/kg/min) overall (p = 0.25), or when stratified by sex (p = 0.21 women, p = 0.69 men). The mean difference between analyzers was - 0.296 ml/kg/min (+/-0.26). Results were not significantly different for VO(2) (ml/min) or VCO2) (ml/min) within the study population (p = 0.16 and p = 0.08, respectively), or when stratified by sex (VO(2): p = 0.51 women, p = 0.16 men; VCO2: p = .11 women, p = 0.53 men).

Conclusion: The Cosmed K4b(2) portable metabolic analyzer provides measures of VO2 and VCO2 during steady-state, submaximal exercise similar to a traditional, stationary gas exchange system.

Show MeSH
Comparison of VCO2 (ml/min) values between the Cosmed K4b2 and Medgraphics metabolic analyzers.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2823789&req=5

pone-0009292-g003: Comparison of VCO2 (ml/min) values between the Cosmed K4b2 and Medgraphics metabolic analyzers.

Mentions: All participants (N = 19) successfully completed both tests. Pearson and intraclass (ICC) correlation coefficients for the average values are shown in Table 2. VO2 normalized for body weight (ml/kg/min), VO2 (ml/min), and VCO2 (ml/min) were highly intercorrelated, suggesting a strong, positive linear relationship. The bar graphs in Figures 1, Figure 2 and Figure 3 clearly show that the values generated by the two different analyzers were nearly super-imposable. The Bland-Altman plot (Figure 4) indicates acceptable limits of agreement between the two systems for VO2 (ml/kg/min), with all but one of the data points falling within two standard deviations of the mean value [18]. Additionally, the Pitman's test of difference in variance indicates that the two groups have identical probability distributions (p = 0.125).


Comparison of the Cosmed K4b(2) portable metabolic system in measuring steady-state walking energy expenditure.

Schrack JA, Simonsick EM, Ferrucci L - PLoS ONE (2010)

Comparison of VCO2 (ml/min) values between the Cosmed K4b2 and Medgraphics metabolic analyzers.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2823789&req=5

pone-0009292-g003: Comparison of VCO2 (ml/min) values between the Cosmed K4b2 and Medgraphics metabolic analyzers.
Mentions: All participants (N = 19) successfully completed both tests. Pearson and intraclass (ICC) correlation coefficients for the average values are shown in Table 2. VO2 normalized for body weight (ml/kg/min), VO2 (ml/min), and VCO2 (ml/min) were highly intercorrelated, suggesting a strong, positive linear relationship. The bar graphs in Figures 1, Figure 2 and Figure 3 clearly show that the values generated by the two different analyzers were nearly super-imposable. The Bland-Altman plot (Figure 4) indicates acceptable limits of agreement between the two systems for VO2 (ml/kg/min), with all but one of the data points falling within two standard deviations of the mean value [18]. Additionally, the Pitman's test of difference in variance indicates that the two groups have identical probability distributions (p = 0.125).

Bottom Line: Average oxygen consumption (VO2) and carbon dioxide production (VCO2) from each walk were compared.Comparison of the average values obtained using the Cosmed K4b(2) and Medgraphics systems using paired t-tests indicate no significant difference for VO2 (ml/kg/min) overall (p = 0.25), or when stratified by sex (p = 0.21 women, p = 0.69 men).Results were not significantly different for VO(2) (ml/min) or VCO2) (ml/min) within the study population (p = 0.16 and p = 0.08, respectively), or when stratified by sex (VO(2): p = 0.51 women, p = 0.16 men; VCO2: p = .11 women, p = 0.53 men).

View Article: PubMed Central - PubMed

Affiliation: Longitudinal Studies Section, Clinical Research Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America. schrackja@mail.nih.gov

ABSTRACT

Background and aims: Recent introduction of the Cosmed K4b(2) portable metabolic analyzer allows measurement of oxygen consumption outside of a laboratory setting in more typical clinical or household environments and thus may be used to obtain information on the metabolic costs of specific daily life activities. The purpose of this study was to assess the accuracy of the Cosmed K4b(2) portable metabolic analyzer against a traditional, stationary gas exchange system (the Medgraphics D-Series) during steady-state, submaximal walking exercise.

Methods: Nineteen men and women (9 women, 10 men) with an average age of 39.8 years (+/-13.8) completed two 400 meter walk tests using the two systems at a constant, self-selected pace on a treadmill. Average oxygen consumption (VO2) and carbon dioxide production (VCO2) from each walk were compared.

Results: Intraclass Correlation Coefficient (ICC) and Pearson correlation coefficients between the two systems for weight indexed VO2 (ml/kg/min), total VO2 (ml/min), and VCO2 (ml/min) ranged from 0.93 to 0.97. Comparison of the average values obtained using the Cosmed K4b(2) and Medgraphics systems using paired t-tests indicate no significant difference for VO2 (ml/kg/min) overall (p = 0.25), or when stratified by sex (p = 0.21 women, p = 0.69 men). The mean difference between analyzers was - 0.296 ml/kg/min (+/-0.26). Results were not significantly different for VO(2) (ml/min) or VCO2) (ml/min) within the study population (p = 0.16 and p = 0.08, respectively), or when stratified by sex (VO(2): p = 0.51 women, p = 0.16 men; VCO2: p = .11 women, p = 0.53 men).

Conclusion: The Cosmed K4b(2) portable metabolic analyzer provides measures of VO2 and VCO2 during steady-state, submaximal exercise similar to a traditional, stationary gas exchange system.

Show MeSH