The difference between the basal metabolic rate and the sleeping metabolic rate in Japanese.
Level 4 - case-series / case-control
Cross-sectional physiological comparative study without randomization or clinical outcome follow-up.
PubMed 15895522 · doi:10.3177/jnsv.50.441
What was done
Basal metabolic rate (BMR) and sleeping metabolic rate (SMR) were measured in a respiratory chamber in 94 healthy Japanese adults (37 males, 57 females; age 39 ± 12 years; body fat 22.0 ± 7.4%). The study assessed the correlation between BMR and SMR, the SMR/BMR ratio, sex differences, and relationships with anthropometric measures.
What was found
SMR was significantly lower than BMR (1416 ± 245 vs. 1492 ± 256 kcal/d), with a strong correlation between the two (r = 0.867, p < 0.001). The mean SMR/BMR ratio was 0.95 ± 0.08 (coefficient of variation: 8.4%). The ratio was significantly lower in males than in females (0.93 ± 0.10 vs. 0.97 ± 0.06, p < 0.05). Anthropometric metrics (age, weight, BMI, body surface area, and percent body fat) showed no significant correlation with the ratio.
Why it matters
The findings confirm that SMR averages 95% of BMR in Japanese adults, demonstrating that substituting BMR for SMR introduces only a minor (around 5%) discrepancy that is of little practical significance in group-level 24-hour energy expenditure estimates.
Limits
The study is restricted to a single healthy Japanese cohort without validation in other ethnic groups, children, elderly, or individuals with metabolic conditions. High inter-individual variability in the SMR/BMR ratio (CV 8.4%) limits the utility of applying group averages to individual-level assessments.
Cited by
- supports Sleeping reduces energy expenditure by 10% to 15%.