414 Nutrition
Authors
W. A. Welch, S. J. Strath, A. M. Swartz
Affiliation
Kinesiology, University of Wisconsin-Milwaukee, Milwaukee, United States
Key words ▶ oxygen consumption ● ▶ energy expenditure ● ▶ indirect calorimetry ● ▶ measurement ●
Abstract
▼
Determine the congruent validity and intra- and inter-day reliability of RMR measures assessed by the ParvoMedics Trueone 2 400 hood dilution method (Parvo) and Cosmed K4b2 (Cosmed) breath-by-breath metabolic systems. Participants underwent 6 RMR assessments over 2 consecutive mornings, 3 with the Parvo (Day 1: Parvo 1; Day 2: Parvo 2, 3), 3 with the Cosmed (Day 1: Cosmed 1; Day 2: Cosmed 2, 3). Measured VE, FEO2, FECO2, VO2, VCO2, kcal/day, and HR values were averaged over a minimum of 10 min. Intra- and inter-day reliability within each system was determined with RMANOVA, and congruent validity was assessed via paired sample t-tests.
Introduction
▼ accepted after revision January 12, 2014 Bibliography DOI http://dx.doi.org/ 10.1055/s-0034-1398575 Published online: February 20, 2015 Int J Sports Med 2015; 36: 414–418 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0172-4622 Correspondence Whitney A. Welch Kinesiology University of WisconsinMilwaukee P.O. Box 413 Milwaukee United States 53202 Tel.: + 1/414/229 5676 Fax: + 1/414/229 3166 [email protected]
Over 66 % of the US population is classified as overweight or obese according to data using body mass index [16]. Obesity increases the risk of chronic diseases such as cardiovascular disease and type 2 diabetes [5]. Research has demonstrated that a 10 % loss of body weight results in a significant increase in health benefits and decreased risk of chronic disease [1]. Therefore, of significant interest are interventional strategies to decrease body weight among overweight and obese individuals. The majority of researchers, dieticians and other clinicians prescribe to the notion that in order to decrease body weight a shift in energy balance must take place, with energy expended exceeding energy taken in, thus creating a negative energy balance [9]. To accurately predict energy expenditure to prescribe energy intake, valid measurements of total daily energy expenditure are needed. There are 3 distinct contributors to total daily energy expenditure; resting metabolic rate (RMR), the thermic effect of food and daily
Welch WA et al. Congruent Validity and Reliability … Int J Sports Med 2015; 36: 414–418
31 participants (13 females, 18 males; 27.3 ± 7 years, 24.8 ± 3.1 kg.m2) completed the study. There were no significant differences in any within or between day Parvo values or Cosmed values. When systems were compared, there was a significant difference between VE (Parvo2: 25.03 L/min, Cosmed2: 8.98 L/min) and FEO2 (Parvo2: 19.68 %, Cosmed2: 16.63 %), however, there were no significant difference in device-calculated RMR (kcals/day). The Parvo and Cosmed are reliable metabolic system with no intra- or inter-day differences in RMR. Due to differences in measurement technology, FEO2, VE were significantly different between systems, but the resultant RMR values were not significantly different.
physical activity. The largest of these portions of total daily energy expenditure is RMR, accounting for 60–75 % of an individuals’ energy expended each day [13]. The most convenient estimate of RMR is to use a prediction equation. However, research has shown these equations often under- or over-estimate RMR in many populations [6]. Therefore, alternative methods that are also easily applied should be used, when applicable, in order to provide a more accurate assessment. Indirect calorimeter measures of energy expenditure have previously been shown to be a feasible and valid means of assessing RMR [8, 10, 12, 17]. 2 indirect calorimeter systems, the Parvo Medics Trueone 2 400 metabolic system (Parvo) (Parvo Medics, Sandy, UT) and Cosmed K4b2 portable metabolic system (Cosmed) (COSMED, Rome, Italy) are commonly used metabolic measurement systems. The Parvo is a laboratory-based metabolic cart system that uses the canopy dilution technique to estimate RMR. The Cosmed is a small, portable breath-by-breath analysis system that is worn by the participant on a harness, and
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
Congruent Validity and Reliability of Two Metabolic Systems to Measure Resting Metabolic Rate
Methods
▼
Participants
Participants were recruited from a large midwestern university and the surrounding metropolitan area. Participants qualified for the study, if they were between the ages of 18–50 years old and were free of any metabolic, cardiovascular or pulmonary diseases. Exclusion from participation included taking any medication that may alter metabolism, inability to lie supine on a table for 90 continuous minutes, or if the participant were pregnant.
Overview
Day 1 *Metabolic systems were randomly ordered.
ParvoMedics Trueone 2400 metabolic system
The ventilated canopy and dilution pump method was used to assess RMR in this study. Prior to all tests, a gas analyzer calibration using a known gas mixture (1.00 % CO2, 19.51 % O2) and flowmeter calibration using a 3 L calibration syringe were performed. Participants were draped with the hood canopy and connected plastic sheet. A breathing tube connected the hood to the metabolic system. Primary outcome variables calculated by the Parvo included: fraction of expired oxygen (FEO2), fraction of expired carbon dioxide (FECO2) and volume of expired air (VE) were sampled within the hood to determine volume of carbon dioxide produced (VCO2), VO2, RQ and kilocalories per day (kcals) values. Parvo data were averaged over 1 min and exported into a spreadsheet.
Cosmed K4b2 portable metabolic system
Prior to all testing the room air, reference gas, delay and turbine calibration were performed. The reference gas calibration used a 5 % CO2, 16 % O2 gas mixture, and the turbine calibration was done using a 3 L calibration syringe. Participants were fitted with a Vmask (Hans Rudolf, Inc., Kansas City, MO) covering their nose and mouth. The mask was secured to the participant’s head using a mesh head strap. All masks were secured while the participants were lying down to ensure a tight seal. Since all testing was performed supine, the system was placed on a table next to the participant. The Cosmed system used breath by breath measurements of FEO2, FECO2 and VE to determine VCO2, VO2, RQ and kcals which were the primary outcome variables. Cosmed data were downloaded to a laboratory computer and averaged over 1 min.
Measurement 5 Cosmed3/Parvo3*
Measurement 4 Cosmed2/Parvo2*
Measurement 3 Cosmed2/Parvo2*
Rest Period
Measurement 2 Cosmed1/Parvo1*
Measurement 1 Cosmed1/Parvo1*
Rest Period
Participants made 2 visits to the laboratory on 2 consecutive mornings, immediately after waking. Prior to each visit participants were instructed to refrain from eating or drinking any calorie- or stimulant-containing items and from exercising for 12 h. During the first visit, participants signed an informed consent approved by the university’s Institutional Review Board, and conducted in accordance with the ethical principles in the Declaration of Helsinki [7]. A health history questionnaire was completed and body height (Detecto 3PHTROD-WM, Webb City, MO) and mass (Detecto 339, Web City, MO) were measured using American College of Sports Medicine standard procedures [15]. Participants were asked to lie on a padded table and were rested for at least 10 min prior to beginning the measurements. All RMR measurements were completed with participants lying supine and they remained lying in between tests. 2 resting met-
abolic rate tests were performed (Parvo1, Cosmed1) followed by body composition measurements using dual energy x-ray absorptiometry. During the second visit, the same pre-participation guidelines were followed. Participants arrived at the laboratory immediately after waking, and were asked to lie and rest for at least 10 min prior to beginning the measurements. 4 resting metabolic rate tests were performed during this visit (Parvo2, Parvo3, Cosmed2, Cosmed3). All RMR tests were randomly ordered (within day) between the 2 metabolic systems. ● ▶ Fig. 1 depicts the protocol of the RMR measurements for both laboratory visits. Additionally, a heart rate monitor (Polar T41, Polar Electro, Kempele, Finland) was worn throughout all metabolic measurement procedures. All metabolic tests were ended once 10 continuous minutes of resting, steady state oxygen consumption (VO2), respiratory quotient (RQ) and heart rate (HR) values were recorded, defined as
Authors
W. A. Welch, S. J. Strath, A. M. Swartz
Affiliation
Kinesiology, University of Wisconsin-Milwaukee, Milwaukee, United States
Key words ▶ oxygen consumption ● ▶ energy expenditure ● ▶ indirect calorimetry ● ▶ measurement ●
Abstract
▼
Determine the congruent validity and intra- and inter-day reliability of RMR measures assessed by the ParvoMedics Trueone 2 400 hood dilution method (Parvo) and Cosmed K4b2 (Cosmed) breath-by-breath metabolic systems. Participants underwent 6 RMR assessments over 2 consecutive mornings, 3 with the Parvo (Day 1: Parvo 1; Day 2: Parvo 2, 3), 3 with the Cosmed (Day 1: Cosmed 1; Day 2: Cosmed 2, 3). Measured VE, FEO2, FECO2, VO2, VCO2, kcal/day, and HR values were averaged over a minimum of 10 min. Intra- and inter-day reliability within each system was determined with RMANOVA, and congruent validity was assessed via paired sample t-tests.
Introduction
▼ accepted after revision January 12, 2014 Bibliography DOI http://dx.doi.org/ 10.1055/s-0034-1398575 Published online: February 20, 2015 Int J Sports Med 2015; 36: 414–418 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0172-4622 Correspondence Whitney A. Welch Kinesiology University of WisconsinMilwaukee P.O. Box 413 Milwaukee United States 53202 Tel.: + 1/414/229 5676 Fax: + 1/414/229 3166 [email protected]
Over 66 % of the US population is classified as overweight or obese according to data using body mass index [16]. Obesity increases the risk of chronic diseases such as cardiovascular disease and type 2 diabetes [5]. Research has demonstrated that a 10 % loss of body weight results in a significant increase in health benefits and decreased risk of chronic disease [1]. Therefore, of significant interest are interventional strategies to decrease body weight among overweight and obese individuals. The majority of researchers, dieticians and other clinicians prescribe to the notion that in order to decrease body weight a shift in energy balance must take place, with energy expended exceeding energy taken in, thus creating a negative energy balance [9]. To accurately predict energy expenditure to prescribe energy intake, valid measurements of total daily energy expenditure are needed. There are 3 distinct contributors to total daily energy expenditure; resting metabolic rate (RMR), the thermic effect of food and daily
Welch WA et al. Congruent Validity and Reliability … Int J Sports Med 2015; 36: 414–418
31 participants (13 females, 18 males; 27.3 ± 7 years, 24.8 ± 3.1 kg.m2) completed the study. There were no significant differences in any within or between day Parvo values or Cosmed values. When systems were compared, there was a significant difference between VE (Parvo2: 25.03 L/min, Cosmed2: 8.98 L/min) and FEO2 (Parvo2: 19.68 %, Cosmed2: 16.63 %), however, there were no significant difference in device-calculated RMR (kcals/day). The Parvo and Cosmed are reliable metabolic system with no intra- or inter-day differences in RMR. Due to differences in measurement technology, FEO2, VE were significantly different between systems, but the resultant RMR values were not significantly different.
physical activity. The largest of these portions of total daily energy expenditure is RMR, accounting for 60–75 % of an individuals’ energy expended each day [13]. The most convenient estimate of RMR is to use a prediction equation. However, research has shown these equations often under- or over-estimate RMR in many populations [6]. Therefore, alternative methods that are also easily applied should be used, when applicable, in order to provide a more accurate assessment. Indirect calorimeter measures of energy expenditure have previously been shown to be a feasible and valid means of assessing RMR [8, 10, 12, 17]. 2 indirect calorimeter systems, the Parvo Medics Trueone 2 400 metabolic system (Parvo) (Parvo Medics, Sandy, UT) and Cosmed K4b2 portable metabolic system (Cosmed) (COSMED, Rome, Italy) are commonly used metabolic measurement systems. The Parvo is a laboratory-based metabolic cart system that uses the canopy dilution technique to estimate RMR. The Cosmed is a small, portable breath-by-breath analysis system that is worn by the participant on a harness, and
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
Congruent Validity and Reliability of Two Metabolic Systems to Measure Resting Metabolic Rate
Methods
▼
Participants
Participants were recruited from a large midwestern university and the surrounding metropolitan area. Participants qualified for the study, if they were between the ages of 18–50 years old and were free of any metabolic, cardiovascular or pulmonary diseases. Exclusion from participation included taking any medication that may alter metabolism, inability to lie supine on a table for 90 continuous minutes, or if the participant were pregnant.
Overview
Day 1 *Metabolic systems were randomly ordered.
ParvoMedics Trueone 2400 metabolic system
The ventilated canopy and dilution pump method was used to assess RMR in this study. Prior to all tests, a gas analyzer calibration using a known gas mixture (1.00 % CO2, 19.51 % O2) and flowmeter calibration using a 3 L calibration syringe were performed. Participants were draped with the hood canopy and connected plastic sheet. A breathing tube connected the hood to the metabolic system. Primary outcome variables calculated by the Parvo included: fraction of expired oxygen (FEO2), fraction of expired carbon dioxide (FECO2) and volume of expired air (VE) were sampled within the hood to determine volume of carbon dioxide produced (VCO2), VO2, RQ and kilocalories per day (kcals) values. Parvo data were averaged over 1 min and exported into a spreadsheet.
Cosmed K4b2 portable metabolic system
Prior to all testing the room air, reference gas, delay and turbine calibration were performed. The reference gas calibration used a 5 % CO2, 16 % O2 gas mixture, and the turbine calibration was done using a 3 L calibration syringe. Participants were fitted with a Vmask (Hans Rudolf, Inc., Kansas City, MO) covering their nose and mouth. The mask was secured to the participant’s head using a mesh head strap. All masks were secured while the participants were lying down to ensure a tight seal. Since all testing was performed supine, the system was placed on a table next to the participant. The Cosmed system used breath by breath measurements of FEO2, FECO2 and VE to determine VCO2, VO2, RQ and kcals which were the primary outcome variables. Cosmed data were downloaded to a laboratory computer and averaged over 1 min.
Measurement 5 Cosmed3/Parvo3*
Measurement 4 Cosmed2/Parvo2*
Measurement 3 Cosmed2/Parvo2*
Rest Period
Measurement 2 Cosmed1/Parvo1*
Measurement 1 Cosmed1/Parvo1*
Rest Period
Participants made 2 visits to the laboratory on 2 consecutive mornings, immediately after waking. Prior to each visit participants were instructed to refrain from eating or drinking any calorie- or stimulant-containing items and from exercising for 12 h. During the first visit, participants signed an informed consent approved by the university’s Institutional Review Board, and conducted in accordance with the ethical principles in the Declaration of Helsinki [7]. A health history questionnaire was completed and body height (Detecto 3PHTROD-WM, Webb City, MO) and mass (Detecto 339, Web City, MO) were measured using American College of Sports Medicine standard procedures [15]. Participants were asked to lie on a padded table and were rested for at least 10 min prior to beginning the measurements. All RMR measurements were completed with participants lying supine and they remained lying in between tests. 2 resting met-
abolic rate tests were performed (Parvo1, Cosmed1) followed by body composition measurements using dual energy x-ray absorptiometry. During the second visit, the same pre-participation guidelines were followed. Participants arrived at the laboratory immediately after waking, and were asked to lie and rest for at least 10 min prior to beginning the measurements. 4 resting metabolic rate tests were performed during this visit (Parvo2, Parvo3, Cosmed2, Cosmed3). All RMR tests were randomly ordered (within day) between the 2 metabolic systems. ● ▶ Fig. 1 depicts the protocol of the RMR measurements for both laboratory visits. Additionally, a heart rate monitor (Polar T41, Polar Electro, Kempele, Finland) was worn throughout all metabolic measurement procedures. All metabolic tests were ended once 10 continuous minutes of resting, steady state oxygen consumption (VO2), respiratory quotient (RQ) and heart rate (HR) values were recorded, defined as
