Background: As a reduction of water spaces is expected in the elderly because of fat-free mass loss, disease is often associated with increased hydration. The present study compared water spaces and cellular hydration in adults, healthy and diseased aged patients.
Methods: An open study was conducted in 6 geriatric wards and a nutrition laboratory involving 85 aged diseased persons, 68 healthy elderly adults, and 35 adults. Total body water (TBW, H(2)(18)O dilution), extracellular water (ECW, Bromide dilution), and fat-free mass (FFM, body density and Siri's equation) were measured directly whereas intracellular water (ICW = TBW - ECW) and body cell mass (FFM - ECW) were obtained by calculations.
Results: FFM, TBW, and ICW were higher in adults than in the 2 other groups and in the elderly than in aged patients. ECW was higher in aged patients than in healthy elderly participants. The proportion of TBW made of ECW or ICW was the same in adults and in healthy elderly persons. A higher proportion of TBW was composed of ECW, and a lower proportion of TBW was composed of ICW, in diseased patients compared with the 2 other groups. The proportion of ICW in body cell mass was also lower in diseased patients.
Conclusions: Diseased elderly persons display reduced ICW and expanded ECW. A cellular dehydration is suggested.