Youth Metabolic Equivalents Differ Depending on Operational Definitions.

Area of Science:

• Exercise Physiology
• Pediatric Health
• Metabolic Research

Background:

• Youth metabolic equivalents (METy) are crucial for assessing physical activity energy expenditure.
• Operational definitions of METy vary, using either predicted basal metabolic rate (METyBMR) or measured resting metabolic rate (METyRMR).
• This inconsistency complicates comparisons across studies and accurate interpretation of youth physical activity levels.

Purpose of the Study:

• To compare the comparability of METyBMR and METyRMR in youth.
• To determine if different calculation methods yield significantly different METy values.
• To inform standardized methodologies for assessing physical activity in pediatric populations.

Main Methods:

• Analyzed indirect calorimetry data from 245 youth (ages 6-18).
• Calculated METyBMR using Schofield equations and METyRMR from 30-minute resting measurements.
• Compared METyBMR and METyRMR across various physical activities using ANOVA and categorized intensity levels.

Main Results:

• A significant interaction was found between activity and METy calculation method (P < 0.001).
• METyBMR was significantly higher than METyRMR for 28 of 31 activities, with differences ranging from 15.6% to 23.1%.
• Intensity classifications matched for both methods in 69.0% of cases.

Conclusions:

• METyBMR and METyRMR demonstrate considerable differences in youth.
• A consensus is needed on the operational definition of metabolic equivalents for youth.
• Clear distinction between METyBMR and METyRMR is essential for accurate research and application.