Phase angle is related with physical function in older adults: a cross sectional study

Abstract

This study aimed to verify a relationship between phase angle (PhA) with physical function in older adults. We also intend to analyse the ability of PhA to predict physical function after adjusting for poten-tial confounders. This cross-sectional study included fifty-six physically independent older adults (age, 70.57 ± 3.79 years; BMI, 28.09 ± 4.37 kg/m2). Bioelectrical impedance analysis was used to measure PhA at 50 KHz. Additionally, physical function was assessed through four functional fitness tests, 30 sec chair‐stand; timed-up & go (TUG test; 6 min walking test and ball throw test). The University of Évora Ethics Committee approved this study (approval no. 22030). It was found moderate correlations between PhA and ball throw test and 6 min walking test (p= 0.005; r= 0.375 and p= 0.003; r= 0.396, respectively) and a small correlation between PhA and 30 sec chair‐stand test (p= 0.035; r= 0.285). No correlation was found between PhA and TUG test. In addition, after adjusting for potential confounders the linear regression analysis demonstrated that PhA was a significant predictor of some functional fitness tests: ball throw test (β= 38.114; p< 0.01; R2= 0.630) and 6 min walking test (β= 575.212; p= 0.001: R2= 0.257). The correlation between PhA and ball throw test may represent that a better cellular and membrane integri-ty can facilitate the ability to recruit motor units and thus, to improve the capacity muscle activation and the force production. Lastly, we can conclude that the PhA is a marker of physical function in independent older adults.