Phase Angle Linked to Sedentary Time and Physical Function in Older Adults

Phase angle, an electrical property measured through bioelectrical impedance spectroscopy, serves as a significant predictor of sedentary time, physical activity, and functional capacity in older adults, according to a study published in BMC Public Health. Researchers investigated cell health indicators captured by bioelectrical impedance spectroscopy to clarify their relationship with objective measures of sedentary behavior, daily movement, and muscle performance, addressing an area where little prior evidence has been established in aging populations.

The investigation analyzed data collected from 96 older adults. The research team evaluated three specific electrical properties using bioelectrical impedance spectroscopy: phase angle, characteristic frequency, and membrane capacitance. Alongside these cellular health markers, the investigators gathered objective assessments of physical activity patterns and administered standardized tests to evaluate muscle strength, mobility, and physical capability.

The physical evaluation protocol incorporated several distinct functional metrics, including handgrip strength, the short physical performance battery, and the timed-up-and-go test. Physical activity assessments captured light physical activity, low physical activity, and total activity counts per day alongside sedentary time. Following data collection, the researchers conducted correlational evaluations and multiple regression analyses to determine the specific relationships between the electrical properties and functional outcomes.

The findings demonstrated that participants with normal phase angle scores exhibited greater light physical activity, higher total daily activity counts, superior grip strength, and higher short physical performance battery scores compared to individuals with low phase angle values. Both phase angle and membrane capacitance correlated negatively with sedentary time and timed-up-and-go duration, while correlating positively with low physical activity, grip strength, and short physical performance battery scores. Conversely, characteristic frequency correlated positively with sedentary time and negatively with low physical activity and grip strength.

When multiple regression analyses were performed to evaluate the independent predictive value of these electrical properties, phase angle emerged as the only significant predictor across all examined outcomes, including sedentary time, low physical activity, total daily activity counts, short physical performance battery scores, and timed-up-and-go performance. Based on these observations, the authors concluded that phase angle may serve as a useful adjunctive indicator for assessing physical activity levels and functional status among older adults.

Subject of Research: Bioelectrical impedance spectroscopy parameters and physical function in older adults

Article Title: Association of electrical properties of bioelectrical impedance spectroscopy with sedentary time, physical activity and muscle function in older adults

Article References: Taani, M. H., Bassindale, K. D., Yamada, Y., Musleh, K., & Andargeery, S. Y. (2026). Association of electrical properties of bioelectrical impedance spectroscopy with sedentary time, physical activity and muscle function in older adults. BMC Public Health. https://doi.org/10.1186/s12889-026-30209-y

Image Credits: AI Generated

DOI: 10.1186/s12889-026-30209-y

Keywords: bioelectrical impedance spectroscopy, phase angle, older adults, physical activity, sedentary time, muscle function, grip strength, functional mobility, Association, electrical, properties, bioelectrical