EE: Rest Period Duration (2013)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
  • To assess if REE measurement is reproducible in stable hospitalized patients
  • To investigate the influence of hospital meals and physical activities on the REE measurements
  • To estimate EE change in patients receiving TPN
  • To assess energy metabolism change after enteral nutritional support.
Inclusion Criteria:
  • Understand and give written consent
  • Conditions in patients that were included depending on the questions to be answered.
Exclusion Criteria:
  • Refusal to consent
  • Not meeting inclusion criteria.
Description of Study Protocol:

REE was measured in different patients under different conditions, depending on the questions to be answered.

Question Number One: Within-patient variability of REE measured in a hospital setting

  • Two REE measurements in the morning
  • Two with a 24-hour interval. Measurements were standardized after an overnight fast.

Questions Number Two: Changes in metabolic rate during the day. The effect of food intake (breakfast, lunch) and physical activity on REE.

  • Stable patients: REE was measured in the morning and in the mid-afternoon, three hours after lunch
  • Lung and colorectal cancer patients: REE was measured early in the morning, while fasting, and a few hours later (mid-morning). Five patients had eaten breakfast, while 12 had not. All patients were ambulatory and had limited activities.
  • Healthy adults: REE was measured at 9:00 a.m, after a 10-hour fast. REE was carried out again after 30 minutes of bed-rest. At second day, subjects spent the night at the hospital and REE was taken the next day, controlling for activities (i.e., controlling for washing, dressing and traveling).

Question Number Three: The effect of the administration of continuous TPN on EE

REE was measured in the morning, before TPN. Second measurement was performed during TPN administration on the ninth day of TPN.

Question Number Four: Effect of nine days' enteral nutritional support on energy metabolism

EE was measured before and after nine days of enteral feedings. Both measurements were performed in the morning.


  • Height measured: Not specified
  • Weight measured: Reported, but not specified
  • Fat-free mass measured: No.


  • Monitored heart rate: Not specified
  • Body temperature: Not specified
  • Medications administered: Not reported, but most likely allowed in lung and colorectal cancer patients.

Resting energy expenditure

  • IC type: Mijinhardt module
  • Equipment of calibration: Yes
  • Coefficient of variation using standard gases: Yes
  • Rest before measure (state length of time rested, if available): After overnight fast
  • Measurement length: 30 minutes at complete rest
  • Steady state: Not specified
  • Fasting length: Overnight (ON)
  • Exercise restrictions XX hours prior to test: Not applicable
  • Room temperature: Not specified
  • Number of measures within the measurement period: One
  • Were some measures eliminated? No
  • Were a set of measurements averaged? No
  • Coefficient of variation in subjects measures: No
  • Training of measurer: Not specified
  • Subject training of measuring process: No
  • Statistical tests
    • Student's paired T-test
    • The Mann-Whitney U-test and the Wilcoxon matched-pairs signed-ranks test were used for non-parametric data.
Data Collection Summary:

Outcomes and Other Measures

  • Measured REE [(VO2, L per minute)
  • VCO2 (L per minute; ml per kg per minute)
  • RQ, ventilation (L per minute).

Blinding Used


Description of Actual Data Sample:

Actual Sample

Varied, based on questions.

Question Number One: Within-patient variability of REE

  • Setting: Hospital
  • N=14 stable hospitalized patients
    [Reviewer’s note: Table indicates 15 stable hospital patients?]
    • Nine males; six females
    • Age: 40±20 years
    • Weight: 74±12kg
    • Percentage IBW: 108±13. 

Questions Number Two: Changes in metabolic rate during the day; the effect of food intake and physical activity on REE

  • Setting: Hospital and research
  • Total: N=62
  • 15 stable hospitalized patients (as discussed in Question Number One)
  • 17 hospitalized patients with lung or colorectal cancer
    • 15 males; two females
    • Age: 70±10 years
    • Weight: 70±10kg
    • Percentage IBW: 100±13
  • 30 healthy adults: 11 males, 19 females
    • Age: 69±7 years
    • Weight: 70±10kg
    • Percentage IBW: 105±11.

Question Number Three: Effect of administration of continuous TPN on EE

14 hospitalized gastric and colorectal cancer patients on enteral feeding

  • Five males; nine females
  • Age: 72±5 years
  • Weight: 63±8kg
  • Percentage IBW: 97±12.
Summary of Results:

Question Number One

No difference in REE between two measurements in the morning. The test-retest reliability coefficient was high (R=0.98; P<0.001). The 95% confidence interval for the difference between repeat measurements was -148kcal to +176kcal per day.

Question Number Two

  • REE measured in mid-afternoon, after lunch, was higher than REE measured in the morning. Mean rise was 15% (243kcal). All patients showed an increase in metabolic rate with a range from less than 5% to 25%.
  • The patients who ate breakfast between the two measurements showed an increase in REE (+8.8±4.9%) in contrast to patients who had not eaten (they showed a decrease in REE: -1.6±4.0%)
  • REE measured in healthy volunteers that had spent the night in the hospital was not significantly different from REE measured according to the normal routine for outpatients. 

Question Number Three

  • EE measured before and after nine days of TPN increased significantly with 11.8% (142±132kcal)
  • RQ increased from 0.77 to a RQ of almost 1.0.

Question Number Four

REE measured before and after nine days of enteral feeding increased only 3.1% (37±49kcal). RQ increased from 0.78 to 0.87. This significance was lessened when REE was expressed per kg body weight (P=0.07).

Measurement Process

  • Number of measurements: Not specified
  • Length of measurements: Not specified.

Measurement Timing

Depended on questions being asked.

Individual Characteristics

Described above.

Author Conclusion:

As stated by the author in body of report:

  • “In our study, REE measured early in the morning after an overnight fast was highly reproducible.”
  • “Results of this study suggest that diet-induced thermogenesis is important even 3 hr after a meal. To avoid the effect of diet-induced thermogenesis in the measurement a patient must be measured in the morning in the post-absorptive state.”
  • “Variations because of limited physical activities maybe neglected, including a short travel from home to the hospital, which implies that REE may be measured in an outpatient basis.”
  • “The effect of TPN on EE was a 12% increase, while 9 days of enteral nutritional support did not increase REE substantially when corrected for the increase in body weight.”
  • “Surprisingly, post-absorptive RQ was 0.87 after 9 days of enteral nutritional support, while RQ was 0.78 before. However, based on the fuel mix oxidized there is still an effect of the enteral feeding on energy metabolism after an overnight fast. This should be considered when energy metabolism is measured in patients under these conditions.”
  • “This study confirmed that TPN-induced thermogenesis is of a similar magnitude to diet-induced thermogenesis of normal oral diets (±10% of energy intake).”
Funding Source:
University/Hospital: University of Limburg, Maastricht, The Netherlands
Reviewer Comments:


  • "Study was clinically relevant and results are applicable."
  • “Included stable patients, ill patients, and healthy adults in analyzing the effect of physical activities in REE measurements.”
  • Discussed impact of weight on REE
  • Appropriate statistical analysis.
  • “Very small sample sizes, and many do not meet n=10 for gender subsamples”
  • “Convenience sample of healthy adults.”
  • “IC measurement process was standardized but steady state and training of measurer not discussed; weighing procedures also not identified. ”
  • “Difficulty with accepting discussion that healthy volunteers in a research setting or hospitalized lung and cancer patients can conclude that REE can be measured in outpatient setting.”
  • “Did not identify intervening variables such as medications or cancer disease stage and treatment variations.”

[Analyst note: Post-prandial increases is suggested as a potential confounding factor in reported group mean REE difference; therefore, was not considered in Conclusion Statement.]

Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? N/A
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? N/A
  1.3. Were the target population and setting specified? N/A
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? N/A
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? N/A
  2.4. Were the subjects/patients a representative sample of the relevant population? N/A
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? No
  4.1. Were follow-up methods described and the same for all groups? N/A
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? N/A
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? No
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? No
  7.1. Were primary and secondary endpoints described and relevant to the question? N/A
  7.2. Were nutrition measures appropriate to question and outcomes of concern? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? N/A
  7.5. Was the measurement of effect at an appropriate level of precision? N/A
  7.6. Were other factors accounted for (measured) that could affect outcomes? N/A
  7.7. Were the measurements conducted consistently across groups? N/A
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? N/A
  8.2. Were correct statistical tests used and assumptions of test not violated? N/A
  8.3. Were statistics reported with levels of significance and/or confidence intervals? N/A
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? N/A
  8.6. Was clinical significance as well as statistical significance reported? N/A
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? N/A
  9.2. Are biases and study limitations identified and discussed? N/A
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? N/A
  10.2. Was the study free from apparent conflict of interest? N/A