Extracellular Water May Mask Actual Muscle Atrophy During Aging
Open Access
- 4 February 2010
- journal article
- research article
- Published by Oxford University Press (OUP) in The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences
- Vol. 65A (5), 510-516
- https://doi.org/10.1093/gerona/glq001
Abstract
Skeletal muscle tissue holds a large volume of water partitioned into extracellular water (ECW) and intracellular water (ICW) fractions. As the ECW may not be related to muscle strength directly, we hypothesized that excluding ECW from muscle volume would strengthen the correlation with muscle strength. A total of 119 healthy men aged 20–88 years old participated in this study. Knee isometric extension strength, vertical jump, and standing from a chair were measured as indices of muscle strength and power in the lower extremities. The regional lean volume (LV), total water (TW), ICW, and ECW in the lower leg were estimated by anthropometry (skinfold and circumference measurements) and segmental multifrequency bioelectrical impedance spectroscopy (S-BIS). Then, we calculated the ECW/TW and ICW/TW ratios. Although ICW and the LV index decreased significantly with age (p < .001), no significant changes in ECW were observed (p = .134). Consequently, the ECW/TW ratio increased significantly (p < .001) with age (young adult, 27.0 ± 2.9%; elderly, 34.3 ± 4.9%; advanced elderly, 37.2 ± 7.0%). Adjusting for this by including the ICW/TW ratio in our models significantly improved the correlation between the LV index and strength-related measurements and correlated with strength-related measurements independently of the LV index (p < .001). The ECW/TW ratio increases in the lower leg with age. The results suggest that the expansion of ECW relative to ICW and the LV masked actual muscle cell atrophy with aging.Keywords
This publication has 31 references indexed in Scilit:
- A whole-body model to distinguish excess fluid from the hydration of major body tissuesThe American Journal of Clinical Nutrition, 2007
- Strength, But Not Muscle Mass, Is Associated With Mortality in the Health, Aging and Body Composition Study CohortThe Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 2006
- Influence of Sarcopenia on the Development of Physical Disability: The Cardiovascular Health StudyJournal of the American Geriatrics Society, 2005
- Estimation of total-body and limb muscle mass in hemodialysis patients by using multifrequency bioimpedance spectroscopyThe American Journal of Clinical Nutrition, 2005
- Body Mass Index, Body Cell Mass, and 4‐Year All‐Cause Mortality Risk in Older Nursing Home ResidentsJournal of the American Geriatrics Society, 2004
- Estimation of segmental muscle volume by bioelectrical impedance spectroscopyJournal of Applied Physiology, 2004
- Age-associated changes in skeletal muscles and their effect on mobility: an operational diagnosis of sarcopeniaJournal of Applied Physiology, 2003
- Skeletal Muscle Mass and Muscle Strength in Relation to Lower‐Extremity Performance in Older Men and WomenJournal of the American Geriatrics Society, 2000
- Aging of skeletal muscle: a 12-yr longitudinal studyJournal of Applied Physiology, 2000
- Dynamics of segmental extracellular volumes during changes in body position by bioimpedance analysis.Journal of Applied Physiology, 1998