Phase Angle has long been linked to nutritional status. This marker is fast becoming recognised as a global health marker in total body health assessment.
So how does it work?
Phase Angle is a direct measurement, (not a calculation using equations) of your cell membrane.
Your cell membrane is made up of a phospholipid bilayer comprising of a hydrophilic (water loving) head, and hydrophobic (water hating) tails.
The conducting ball of the membrane is positioned either side of an insulating middle (hydrophobic) making up the cell membrane. When there are two conducting materials surrounding an insulator we call this a capacitor. A capacitor is a device that stores electrons. This is principally what the membrane does. It acts as a capacitor, similar to a battery.
When the cell membrane (or capacitor) loses its ability to function efficiently (ie in cases of malnutrition or disease) it effectively loses its ability to store electrons and can no longer function as an effective capacitor. This is what the Phase Angle picks up. The Phase Angle is the measurement of the functionality of the cell membrane, ie how well our battery is working. If there are leaks in the cell membrane the ability of the cell membrane to hold on to voltage will decrease, thus the Phase Angle will decrease.
A high Phase Angle shows good health, and a low Phase Angle shows a worse status of health.
Please remember that individual’s Phase Angles are very different, and as it stands at the moment, there are no standardisations for population groups.
There are two elements in Phase Angle: Reactance (X) and Resistance (R).
The phase angle φ is the shift between AC current and voltage on the measured impedance (50kHz).
The expression for the phase angle φ is: φ = arctg X/R
Reactance reflects the body cell mass, and the resistance reflects the water or fluid in the body.
Thus fluid and muscle mass will influence the Phase Angle.
A higher Phase Angle could mean an increase in muscle mass (body cell mass) or a decrease in fluid, either from recovery from infection or injury (a good thing!) or a decrease in fluid from dehydration (a bad thing!). A loss of fat could also increase Phase Angle.
A lower Phase Angle could mean a loss of muscle mass (a bad thing), or an increase of fluid (rehydrating which is a good thing, or sign of inflammation or infection – a bad thing), or gaining fat (which could be a good or bad thing depending on your state of health).
So in Summary:
Increased Phase Angle: 1) Gain in muscle mass 2) Decrease in fluid 3) Decrease in fat
Decreased Phase Angle: 1) Loss of muscle tissue 2) Increase in fluid 3) Increase in fat
A low phase angle will simply alert you into looking further as to what might be the case. The body composition measurements on your Bodystat machine will indicate further as to your status within the three body compartments estimated by BIA. So through a full body measurement you should have an idea why your Phase Angle is high or low.