Phase angle is associated with muscle health and cardiorespiratory fitness in older breast cancer survivors

Background & aim: Phase angle (PhA) obtained from bioelectrical impedance analysis (BIA) is an indicator of cellular integrity and relates to several chronic conditions. The purpose of this secondary analysis was to evaluate the association of PhA with health-related physical fitness, namely, cardiorespiratory fitness, skeletal muscle volume, and myosteatosis (i.e. muscle health) in older breast cancer survivors.

Methods: Twenty-two women ≥60 years with a body mass index (BMI) ≥25 kg/m² and who completed chemotherapy for early-stage breast cancer were included. BIA, cardiopulmonary exercise tests and magnetic resonance imaging scans were completed before and after eight weeks of time-restricted eating.

Results: At baseline, PhA was associated with cardiorespiratory fitness (R² = 0.54, p < 0.01) and skeletal muscle volume (R² = 0.83, p < 0.01) and myosteatosis (R² = 0.25, p = 0.02). Results were similar at follow-up.

Conclusion: Findings from this pilot study suggest that higher values of PhA are associated with better health-related physical fitness among older breast cancer survivors.