Effect of somatotypes on lung volumes, capacities and respiratory impedance: A pilot study

The current morphological condition of an individual is described by a somatotype, which is a three-number scale. The endomorph, mesomorph and ectomorph components are presented in the same sequence, and each number corresponds to one of the three basic components of body composition.

We recruited 50 healthy male subjects with a mean age of 24.10 ± 4.55 yrs. Somatotype was determined by the Heath and Carter method. Impulse oscillometry was performed followed by spirometry according to the European Respiratory Society (ERS) or American Thoracic Society (ATS) guidelines. Resistance at 5 Hz (R5) %pred, R20%pred, R5-R20, X5%pred, X20, area of reactance (Ax) and resonant frequency (Fres) were obtained by doing impulse oscillometry. Slow vital capacity (SVC), forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC ratio and maximum mid-expiratory flow (MMEF) were assessed by doing spirometry.

Endomorphs (0.05 (0.00-0.09) vs 0.01 (0.00-0.04); P < 0.0001) and mesomorphs (0.04 (0.000.09) vs 0.01 (0.00-0.04); P = 0.002) had significantly higher R5-R20 than ectomorphs. Similarly, endomorphs (0.32 (0.07-0.82) vs 0.15 (0.08-0.35); P = 0.001) and mesomorphs (0.28 (0.17-0.64) vs 0.15 (0.08-0.35); P = 0.015) also showed significantly higher Ax than ectomorphs, Fres of endomorphs (15.37 (8.43-21.85) vs 10.08 (8.94-14.30); P < 0.0001) and mesomorphs (14.32 (10.24-20.86) vs 10.08 (8.94-14.30); P < 0.0001) were significantly high than ectomorphs. Moreover, spirometric measures reveal significant variation in which mesomorphs had significantly higher values of % predicted of FVC than ectomorphs (92.49 ± 7.211 vs 83.86 ± 7.861; P = 0.042) and the ratio of FEV1 to FVC was significantly higher in ectomorphs than in endomorphs (89.00 ± 5.80 vs 85.04 ± 5.73; P = 0.03).

Peripheral airway dysfunction was observed in endomorphs and mesomorphs as compared to ectomorphs. Mesomorphs had a relatively higher FVC that may be due to their greater muscular strength.