Cellular Hydration & Phase Angle

Beyond Simple Resistance

Standard consumer bioelectrical impedance (BIA) scales measure one thing: Resistance (R). They send a current through your body and measure how much the tissue resists the flow.

However, clinical-grade BIA machines (like InBody or Seca) measure a second, far more important variable: Reactance (Xc).

Reactance is the ability of your cell membranes to store an electrical charge (capacitance). Healthy, robust cells with intact lipid bilayers store charge effectively. Damaged or malnourished cells do not.

What is Phase Angle?

The Phase Angle is the relationship between Resistance and Reactance. It is calculated geometrically and expressed in degrees.

Phase Angle = Arctangent (Reactance / Resistance) × (180 / π)

It is widely considered one of the most accurate biomarkers for overall cellular health and nutritional status, completely independent of total body weight or body fat percentage.

Interpreting Phase Angle Scores

A high phase angle indicates large quantities of intact cell membranes and excellent intracellular hydration (meaning your muscles are full and healthy). A low phase angle indicates cell death, malnutrition, or severe dehydration.

• < 4.0°: Severe malnutrition or systemic disease.
• 4.0° - 5.0°: Poor cellular health. Often seen in chronic dehydration or extreme, prolonged caloric deficits.
• 5.0° - 7.0°: Normal, healthy adult population.
• 7.0° - 9.0°: Highly trained athletes. Indicates massive intracellular water storage (glycogen) and pristine cellular integrity.
• > 9.0°: Elite professional athletes (frequently seen in elite powerlifters and bodybuilders).

Phase Angle and Dieting

When you enter a severe caloric deficit to lose body fat, you are inducing controlled starvation. Over time, cellular integrity degrades and intracellular water drops.

If you take an advanced BIA scan every 4 weeks during a diet phase:

• Good Result: Body fat percentage drops, Phase Angle remains stable (e.g., drops from 7.2 to 7.0). You are losing fat while maintaining cellular health.
• Bad Result: Body fat percentage drops, but Phase Angle crashes (e.g., drops from 7.2 to 5.5). You are burning lean tissue, severely dehydrated, and metabolically crashing.

Phase angle is the ultimate lie-detector for "crash diets." You might lose scale weight, but the phase angle will prove you destroyed your cellular health to do it.