Effects of body composition on metabolism in deer mice ranging in age from 27 days to 1827 days
| . | . | V̇O2max . | . | V̇O2sum . | . | ||
|---|---|---|---|---|---|---|---|
| . | BMR . | Age < breakpoint . | Age > breakpoint . | Age < breakpoint . | Age > breakpoint . | ||
| Body composition . | (N=54) . | (N=25) . | (N=30) . | (N=25) . | (N=30) . | ||
| Heart mass | r=0.337, P=0.0145* | r=0.642, P=0.00126* | r=0.236, P=0.233 | r=0.443, P=0.0387 | r=0.333, P=0.0827 | ||
| Lung mass | r=0.266, P=0.0565 | r=0.604, P=0.00287* | r=0.358, P=0.0612 | r=0.420, P=0.0515 | r=0.392, P=0.0394 | ||
| % fat content | r=0.298, P=0.0320 | r=0.601, P=0.00307* | r=0.128, P=0.516 | r=0.439, P=0.0408 | r=0.424, P=0.0245 | ||
| Hematocrit | r=0.280, P=0.0443 | r=0.413, P=0.056 | r=0.231, P=0.237 | r=0.462, P=0.0305 | r=0.347, P=0.0705 | ||
| . | . | V̇O2max . | . | V̇O2sum . | . | ||
|---|---|---|---|---|---|---|---|
| . | BMR . | Age < breakpoint . | Age > breakpoint . | Age < breakpoint . | Age > breakpoint . | ||
| Body composition . | (N=54) . | (N=25) . | (N=30) . | (N=25) . | (N=30) . | ||
| Heart mass | r=0.337, P=0.0145* | r=0.642, P=0.00126* | r=0.236, P=0.233 | r=0.443, P=0.0387 | r=0.333, P=0.0827 | ||
| Lung mass | r=0.266, P=0.0565 | r=0.604, P=0.00287* | r=0.358, P=0.0612 | r=0.420, P=0.0515 | r=0.392, P=0.0394 | ||
| % fat content | r=0.298, P=0.0320 | r=0.601, P=0.00307* | r=0.128, P=0.516 | r=0.439, P=0.0408 | r=0.424, P=0.0245 | ||
| Hematocrit | r=0.280, P=0.0443 | r=0.413, P=0.056 | r=0.231, P=0.237 | r=0.462, P=0.0305 | r=0.347, P=0.0705 | ||
BMR, basal metabolic rate; V̇O2max, maximal oxygen consumption in exercise; V̇O2sum, maximal oxygen consumption in thermogenesis.
Age breakpoints for V̇O2max and V̇O2sum (485 days and 483 days, respectively) were obtained from the complete data set(Table 2). Regressions were based on loge-transformed metabolic data and included the effects of loge-transformed lean tissue mass and age. Partial rand P values are shown; P values that remained significant after Bonferroni correction are indicated with asterisks (adjustedα=0.0167 for BMR and 0.0036 for V̇O2max and V̇O2sum).