The evolution of bioimpedance analysis: From traditional methods to wearable technology.

Body composition assessments are essential for understanding health and nutritional status. Traditional methods like deuterium oxide dilution, while accurate, are impractical due to cost and complexity. Bioimpedance analysis (BIA) has emerged as a preferred clinical and research technique. BIA measures total body water and, by extension, fat mass and fat-free mass, based on constant hydration assumptions. Wearable BIA technology provides real-time body composition data, enhancing at-home monitoring. Although these devices show promise in measuring parameters like body fat percentage and skeletal muscle mass, accuracy discrepancies compared to methods like dual-energy X-ray absorptiometry and the 4-compartment model require further validation. Addressing user adherence and environmental limitations is essential for reliable results. This narrative review examines the current landscape of wearable BIA technology. Despite challenges, wearable BIA devices offer significant benefits, emphasizing ongoing innovation and validation.