Energy Expenditure

EE: Evidence Analysis: Measuring RMR with Indirect Calorimetry (IC) (2006)

Measuring RMR with Indirect Calorimetry: What Does the Evidence Tell Us?

Measuring resting metabolic rate with indirect calorimetry is a way to improve the accuracy of the RMR value as compared to the common prediction equations. However, IC is not free from error. Another evidence analysis project conducted by the ADA examined factors that may impact indirect calorimetry measurements in healthy and ill populations.

Three broad areas were evaluated for their impact upon IC:

  1. the procedures (e.g., length of measurement, type of equipment)
  2. timing (e.g., physical activity, food ingestion)
  3. intra-subject variability (e.g., circulatory hormones, medication use) (1).

Summary of the Evidence

Table 4 summarizes the conclusion statements for each of the factors evaluated.

Table 5 includes the medications examined as part of the evidence analysis.

The full description of the evidence analyzed is provided in the Evidence Analysis Library 

Additional Factors To Consider in Indirect Calorimetry

Additional factors for consideration when measuring RMR include:

  • equipment malfunction
  • a patient/client’s ability to tolerate and comply with IC measurement
  • practitioner’s access to and competency in using IC

Yet with these considerations, IC can provide a more accurate RMR value if appropriate conditions exist and all of the factors potentially impacting RMR are taken into consideration.