Effect of resistance training on bioelectrical phase angle in older adults: a systematic review with Meta-analysis of randomized controlled trials

Abstract

Resistance training has been proposed as a valid practice to counteract the aging effect on body mass and its components, which can be easily evaluated though the bioelectrical impedance analysis. This study aimed to achieve a systematic review with meta-analysis on the impact of resistance training on bioelectrical proprieties in older adults.A literature review was done in four electronic databases up to 1 January 2022. The inclusion criteria were: (i) participants aged ≥ 60 years; (ii) resistance training lasted ≥ 8 weeks; (iii) measurement of raw bioelectrical parameters in randomized controlled study designs.The outcomes of the trial had to be bioelectrical phase angle (PhA), resistance (R), and reactance (Xc). The methodological quality was assessed using the Rosendal scale.Overall, seven studies with a total of 344 participants were eligible for the analysis. The quality assessment yielded a score of 71.3%. Bioelectrical PhA (0.52 degree [95%CI 0.32, 0.71], p < 0.001) and Xc (3.58 ohms [95%CI 1.97, 5.19], p < 0.001) increased, whereas R decreased (-28.50 ohms [95%CI -41.39, -15.60], p < 0.001) after the resistance training programs.In this meta-analysis, resistance training promoted increases of PhA, which result from an increase in Xc concomitant with a reduction in R. According to the bioimpedance vector analysis, resistance-trained people experienced a beneficial leftward vector displacement, whilst inactivity induced a rightward vector displacement within the R-Xc graph. In future, more sophisticated and rigorous studies that address specific criteria, methods and targeted designs are required to identify which equipment and protocols allow for an optimization of the resistance training effects.Registration code in PROSPERO: CRD42020168057.

Role of phase angle in older adults with focus on the geriatric syndromes sarcopenia and frailty

“…Whether phase angle also reflects acute changes achieved by exercise or by phases of detraining has been studied in older adults. One systematic review summarizing seven studies showed in their meta-analysis that resistance training induced increases in phase angle, which result from an increase in reactance with a concomitant reduction in resistance [61].…”

Phase angle, muscle tissue, and resistance training

“…When looking at the impact of RT on BIA properties of older adult populations, the most up-to-date evidence suggests positive effects of exercise programs on PhA (Table 1). Two systematic reviews with meta-analysis [101,102] have recently addressed this issue, providing valid evidence that distinct RT programs affect PhA depending on the combined or independent effect of increasing Xc and/or decreasing R (Fig. 3B1).…”

“…3B1). By following the previous analysis model adopted by Campa et al [101], and only considering RT programs without the influence of other exercise types and diet/supplementation, we identified eleven intervention studies exploring the effect of RT on PhA in light of changes in other BIA-derived components (i.e., Xc and R). Although PhA was found to increase by about + 1.9 to + 10.6% in all 8 to 24-week RT programs, with the largest improvements being observed in response to RT of greater duration and/ or intensity, the relative contribution of Xc and R did not follow the same trend, thus allowing us to identify three profiles, as presented on Fig.…”

“…There are still some challenges that need to be addressed to further improve our understanding of how changes in R and Xc can be improved through RT programs. First, there is a need to extend RT programs to children and adolescents and other underexplored adult populations (e.g., unhealthy individuals) following the recommendations of the recently available evidence [101,102]. Moreover, future investigations adopting RT programs should also consider adopting different types of strength training (e.g., training to failure), diet/supplementation (e.g., high-protein diet), and combination of different exercise types, to further understand their implications at the cellular level, and their consequent contributions to changes in muscle quality markers.…”

Bioelectrical impedance phase angle is associated with physical performance before but not after simulated multi‐stressor military operations

“…A change in bioelectrical impedance properties, including cellular membrane integrity or intracellular (ICW)/extracellular water (ECW) distribution directly affect Xc and R, resulting in a shift of the PhA (Francisco et al, 2020 ; Silva et al, 2014 ; Stobaus et al, 2012 ; Toso et al, 2000 ). Specifically, increases in body water result in decreased R (Campa, Colognesi, et al, 2022 ; Lukaski et al, 2019 ; Lukaski & Raymond‐Pope, 2021 ; Piccoli et al, 1994 ), whereas increases in body cell mass, cellular membrane integrity, and membrane storage capacity increase Xc (Stobaus et al, 2012 ). The interaction of Xc and R resulting in a high PhA therefore signifies greater body cell mass, cellular membrane integrity, and cellular function (Campa, Colognesi, et al, 2022 ; Custodio Martins et al, 2022 ).…”