Body composition and the expiratory reserve volume of pre-pubertal lean and obese boys and girls.

Previously, we examined the expiratory reserve volume (ERV) of the lungs as a function of percentage body fat in an adult population (age range 18-58 years). A negative correlation resulted when ERV (expressed as a percentage of vital capacity, (ERV/VC) x 100) was regressed on percentage fat for both sexes. In the present study, similar comparisons were made for 33 pre-pubertal boys and girls (aged 7-12.5 years). The regression equation for the boys ((ERV/VC) x 100 = 44.2 - 0.56%fat, r = -0.77, P = 0.002) was similar to that of the adult men ((ERV/VC) x 100 = 48.7 - 0.80 %fat, r = -78) and women ((ERV/VC) x 100 = 49.5 - 0.63 %fat, r = -0.70). However, the girls studied did not follow the same pattern. In this group of pre-pubertal girls, a significant increase in (ERV/VC) x 100 with increasing body fatness was seen ((ERV/VC) x 100 = 29.3 + 0.19 %fat, r = 0.48, P = 0.03). In all four groups, no correlation was seen with age or height. Whereas there was a significant correlation between weight and (ERV/VC) x 100 in the adults, no such relationship was evident in the younger subjects. In pre-pubertal obese girls limited upper body muscle development, perhaps as a result of limited physical activity, may explain the different relationship between ERV and body fatness.

Fat-free mass in relation to stature: ratios of fat-free mass to height in children, adults, and elderly subjects.

A cross-sectional relationship of fat-free mass to height expressed as a ratio (FFM:ht) is presented for 1103 people aged 6-86 y. Data are presented for 13 specific age groups by gender. By providing information for normal, healthy individuals, these data may be of comparative value for nutritionists and clinicians concerned with body composition of patients with wasting diseases. The data were collected over 20 y in our laboratory by using the same densitometric procedure. A significant increase in FFM:ht occurs during the preadolescent and adolescent years. The adolescent spurt continues for a longer period for boys than for girls, resulting in a significant gender difference beginning at approximately age 16 y and continuing throughout adulthood. A decline in FFM:ht, not statistically significant, appears to occur in men greater than 60 y of age, and a significant decline occurs among women greater than 50 y of age (alpha less than 0.01). Thus, both gender- and age-related trends that have implications for the interpretation of comparative body-composition status are suggested.

Body composition and expiratory reserve volume in female gymnasts and runners.

Previous research in this laboratory demonstrated a reduction in expiratory reserve volume of the lungs (ERV) with increasing body fatness (%F, by densitometry). The present study was done to determine if smaller ERV values could be demonstrated in lean female athletes with greater than normal upper-body muscle development. Expiratory reserve volume, vital capacity (VC), and segmental body volumes by densitometry were measured in members of two collegiate women's teams--gymnastics (G) (N = 10) and track (R) (N = 10). The runners provided a control group by being similar to gymnasts in age, weight, and body fatness, but they did not engage in upper-body weight training or gymnastic exercises. The two groups were not significantly different in body weight (means G +/- SD = 53.0 +/- 6.1 kg; means R = 50.8 +/- 4.6 kg) or %F (means G = 16.8 +/- 3.2%; means R = 14.8 +/- 3.8%), but R subjects were taller (means = 165.4 +/- 5.5 cm vs 158.7 +/- 4.8 cm, P less than 0.01). Expiratory reserve volume, expressed as a percent of VC, (ERV X VC-1) 100, was significantly (P less than 0.001) less in the gymnasts (means +/- SD = 29.7 +/- 7.1) as compared to the runners (43.1 +/- 6.4). All other lung capacities as volumes were comparable in both groups. Arm and thorax volumes indicated greater upper-body size in the G subjects (arm volume, means +/- SD of G = 4.8 +/- 0.6 liters, of R = 4.0 +/- 0.6 liters, P less than 0.01; thorax volume, means +/- SD of G = 7.8 +/- 1.4 liters, or R = 5.6 +/- 1.0 liters, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Body composition and the expiratory reserve volume in lean and obese men and women.

The expiratory reserve volume (ERV) of the lungs was determined in 40 women and 34 men over a wide range of age (18-58 years) and percent body fat (3.6-48.6 percent). A negative correlation with percent body fat resulted when the ERV values were expressed as a percent of the vital capacities (ERV/VC . 100). The regression equations were: for women, ERV/VC . 100 = 49.5 -0.63 %F, r = -0.70, SEE = 7.77; for men, ERV/VC . 100 = 48.7 -0.80 %F, r = -0.78, SEE = 6.05. No significant correlation with age or height was found for either sex.

Respiratory flow integrator with improved stability.

A circuit was designed for integrating respiratory flow signals over time to produce volume signals. The circuit involves a simple integrator and three compensation subcircuits which control integrator drift caused by ambient temperature changes, flow signal base-line errors, and random signal errors. A functional unit built according to the circuit design requires initial adjustment, but no further adjustment before or during sustained use. Integration errors are typically less than 1%. The only flow signal requirements are that they be bidirectional and within the human physiological frequency range.