Phase angle
Also called: bioimpedance phase angle, BIA phase angle
What it means
Phase angle is a number from a bioimpedance body composition scan that reflects the health of your cell membranes and roughly indicates muscle quality and cellular vitality.
Since muscle supports bone, a low phase angle can be an early sign of muscle loss that may also signal higher fall and fracture risk.
Phase angle comes from a bioelectrical impedance analysis (BIA) scan, the same kind of device used to estimate body composition (like an InBody machine). A small, painless electrical current passes through your body, and the device measures how the current is delayed as it crosses cell membranes. That delay, measured in degrees, is the phase angle.
A higher phase angle generally reflects healthier, more intact cell membranes and better cellular function, and it tends to track with more lean mass and muscle quality. A lower phase angle is often seen with aging, inactivity, illness, or muscle loss, though it's a general wellness marker rather than a diagnostic test on its own.
Phase angle isn't a bone density measurement and doesn't replace a DEXA scan, but muscle and bone health are closely linked. Since muscle helps support bone through mechanical loading, tracking phase angle alongside grip strength or gait speed can give a fuller picture of overall musculoskeletal health as you age.
A low phase angle can hint at early muscle loss, which raises fall and fracture risk.
Where this leads
WordA low phase angle can signal early muscle loss. See how this connects to sarcopenia, the broader age-related muscle and bone decline.
Related words
Body composition is the breakdown of your body into fat mass, lean (muscle) mass, and bone, usually measured by a…
InBody is a body composition analyzer that uses a painless electrical current (bioelectrical impedance) to estimate…
Lean mass is mostly your muscle weight — the non-fat part of your body. It's tracked because it's closely linked to…
Sarcopenia is the gradual loss of muscle mass and strength that comes with aging, and it's closely tied to bone health.
Muscle quality refers to how well muscles function \u2014 their strength and efficiency relative to size \u2014…
Grip strength is how hard you can squeeze with your hand, measured with a device called a dynamometer. It's used as…
Education only, not medical advice. Decisions about tests, medications and treatment belong with your own doctor. OsteoStrong does not diagnose, treat or cure any disease.
