Understanding Lean Mass in ShapeScaleUpdated 5 months ago

Lean mass is a key body composition metric reported by ShapeScale. It represents your total body mass minus your fat mass and bone mass. This lean mass value includes your muscle tissue, but also accounts for other lean body components such as organs, connective tissue, and water.

What Does Lean Mass Include?

ShapeScale's lean mass measurement encompasses several components of your body:

• Muscle tissue
• Organs (brain, heart, liver, kidneys, etc.)
• Connective tissues (tendons, ligaments)
• Water (intracellular and extracellular)
• Glycogen (stored carbohydrates)

Because lean mass includes variable components like water and glycogen, it can fluctuate in the short-term based on factors such as hydration levels, food intake, and exercise.

Lean Mass vs. Muscle Mass

While muscle tissue is a major component of lean mass, the two terms are not interchangeable. Muscle mass specifically refers to the weight of your muscle tissue, while lean mass includes muscle along with other non-fat, non-bone tissues.

Changes in lean mass over a longer period (several weeks or months) do tend to correlate strongly with changes in muscle mass. However, short-term fluctuations in lean mass don't necessarily reflect muscle gains or losses.

Factors Affecting Lean Mass

Several factors can influence your lean mass reading on ShapeScale:

• Hydration: Your body's water content can shift lean mass up or down.
• Food Intake: The weight of food in your digestive system contributes to lean mass.
• Exercise: Engaging in physical activity can temporarily increase lean mass due to factors like increased blood flow and muscle swelling.
• Muscle Glycogen: The amount of glycogen stored in your muscles can affect lean mass.

Due to these variables, it's common to see small day-to-day fluctuations in lean mass that may not reflect changes in muscle tissue.

Tracking Lean Mass Changes

When assessing changes in lean mass, it's important to look at trends over time rather than focusing on single readings. Consistent, long-term changes in lean mass are more likely to indicate shifts in muscle mass.

To minimize the impact of short-term variables, aim to measure your body composition under consistent conditions. This means scanning at the same time of day, in a similar hydration and feeding state.

Coming Soon: Appendicular Lean Mass (ALM)

To provide an even more targeted metric for tracking muscle changes, ShapeScale will soon introduce Appendicular Lean Mass (ALM). ALM measures the lean mass specifically in your arms and legs.

Since approximately 75% of your body's total muscle mass is located in the limbs, ALM provides a strong reflection of your muscle tissue. By excluding the core and trunk, ALM is also less influenced by fluctuations in water and digestive contents.

Stay tuned for the release of ALM, which will offer an ideal way to reliably assess muscle gains or losses over time.