|
The association of age and weekly swim training distance with body water, lean tissue, fat mass and regional adiposity was examined in 27 male masters swimmers. Subjects ranged in age from 25.3 to 73.1 years (mean age = 47.7 ± 11.1 years). Weekly swim distances, estimated from self-reported swim logs, were from 3 400 to 17 500 m and averaged 10 016 ± 4 223 m. Total body water (TBW), and extracellular water (ECW) were predicted from multi-frequency bioelectrical impedance analysis and intracellular water was estimated by difference. Lean soft tissue, bone mineral content, fat mass, and percent body fat were estimated from dual-energy X-ray absorptiometry. Measures of skinfold thickness, waist circumference, and abdominal sagittal diameter provided an indication of regional adiposity. Total body water, ECW, and ICW mean values (ranges) were as follows: 47.4 ± 4.6 L (37.9-56.9 L), 19.6 ± 1.8 L., (16.4-24.8 L), and 27.8 ± 3.2 L (21.5-34.4 L). Mean percent body fat levels were 21.9 ± 6.6% and ranged from 10.3 to 34.9%. Age was negatively associated with ICW (p = 0.02) and with the ICW/TBW ratio (p = 0.00). Multiple-linear regression analysis backward method suggested that both lean tissue and fat mass were predictors of ICW although the association with fat mass did not reach statistical significance (p = 0.00 and p = 0.06 for lean and fat mass respectively). There was a tendency for greater lower abdominal thickness with increasing age (p = 0.08), but no other associations were observed between age or with swimming and body composition variables. Changes in ICW and the ration of ICW to TBW appeared to be the strongest marker of aging in this group of adult male competitive swimmers. |
