Bio-Impedance Analysis (BIA)
body composition analysis (BIA) measures body composition
electronically. Body composition analysis is the clinical assessment of
tissue and fluid compartments in the human body. Body bioimpedance
analysis is used in preventative, diagnostic, and therapeutic
applications. A normal distribution of tissue and fl uid in the body is
associated with immunity, high function, and longevity. An abnormal
distribution of tissue and fluid in the body is associated with
susceptibility, low function, and the effects of disease and aging. Our
body is bioelectric and the Body bioimpedance analysis measures our
vitality at a cellular level.
Understanding Your Body Bio-Impedance Analysis results
Phase angle is an indicator of cellular health and integrity. Research
on humans has shown that the relationship between phase angle and
cellular health is increasing and nearly linear. A low phase angle is
consistent with an inability of cells to store energy and an indication
of breakdown in the selective permeability of cellular membranes. Cell
membranes have a high lipid content therefore this reading gives an
indication of your cell lipid status. A high phase angle is consistent
with large quantities of intact, healthy cell membranes and body cell
Phase angles for adults
range from 3 - 10 degrees, with normal values of 6 to 8 degrees. A
phase angle of 5’or lower can indicate a serious energy deficiency. A
phase angle higher than 8' is excellent.
Body capacitance is the absolute amount of energy storage of the body
due to intact cellular membranes. A high capacitance indicates that
your body stores energy effec- tively. A low capacitance would suggest
that your cells are having trouble storing energy. Normal values are between 500 to 1000 pF.
Resistance: Resistance is the ratio of electrical potential to the
current in a material. A material with low resistance conducts well
whilst a material with high resistance conducts poorly. The primary
conductor in the human body is water. In the human body, a low
resistance is associated with large amounts of lean body mass. A high
resistance is associated with smaller or low amounts of lean body mass.
Resistance helps to calculate the amount of water in the body. Low
resistance, indicating high conductivity, is due to large amounts of
water in the body. Resistance in the body is proportional to the amount
of lean body mass since water is contained solely within lean body
Reactance: Reactance is a measure of the cells' ability to store
energy. A body that stores energy easily has high reactance and a body
that stores energy poorly has low reactance. Energy is stored in the
cell membrane therefore this reading gives an indication of the amount
of intact cell membranes in the body. Since intact cellular membranes
are contained primarily within body cell mass, the reactance of the
body is proportional to the amount of body cell mass. The reactance
helps to calculate the proportion of the body that is metabolically
Body Cell Mass (BCM): BCM contains all the metabolically active tissues
(living cells) of the body, including muscle cells, organ cells, blood
cells and immune cells. BCM includes the "living" portion of fat cells
but not the stored fat lipids and also includes the water inside living
cells called intracellular water. The main electrolyte of intracellular
water is potassium.
Extracellular Mass (ECM): ECM contains the metabolically inactive parts
of the body components including bone minerals, and blood plasma. ECM
also includes water contained outside living cells called extracellular
water. The main electrolyte of extracellular water is sodium.
Body Cell Mass and Extracellular Mass are used to calculate the ECM/BCM ratio (see below).
ECM/BCM Ratio: This is the ratio of extracellular mass to body cell
mass. A low value is desirable and indicates a high ratio of body cell
(active) mass to extracellular (inactive) mass. Normal values are typically near 1.0, indicating a 50/50 distribution of body cell mass and extracellular mass.
Fat-Free Mass: Fat-free mass, also referred to as lean body mass, is
the total amount of nonfat (lean) parts of the body. It consists of
approximately 73% water, 20% protein, 6% mineral, and 1% ash. Lean body
mass contains virtually all the body's water, all the metabolically
active tissues and bone, and is the source of all metabolic caloric
expenditure. Lean body mass is further divided into body cell mass
(BCM) and extracellular mass (ECM).
Fat Mass: Fat mass is all the extractable lipids from adipose and other
tissue in the body. It is the total amount of stored lipids (fats) in
the body and consists of subcutaneous fat and visceral fat.
Subcutaneous fat is located directly beneath the skin and serves as an
energy reserve and as insulation against outside cold. Visceral fat is
located deeper within the body and serves as an energy reserve and as a
cushion between organs. Everyone needs a certain amount of fat in their
body. The ideal fat % is dependent on age and gender.
Basal metabolic Rate (BMR): This is the number of calories consumed and
metabolized at a normal resting state over a 24 hour period. For a
typical person, BMR accounts for more than 90% of their total daily
expenditure - more than 90% of calories are burned while the person is
The basal metabolic rate is determined by lean body mass since only
lean body mass metabolizes. The greater the individual's lean body
mass, the greater the rate of caloric expenditure. One of the main
benefits of exercise is the maintenance of lean body mass.
Dieting alone may cause a reduction in lean body mass and can actually
reduce the body's ability to burn calories. The main principle of
weight management is to maintain or increase lean body mass. Since this
is not always possible during weight loss, the goal is to minimize
reduction of lean body mass. A typical person will experience a loss of
0.45 pounds of lean body mass and 0.55 pounds of fat mass for each
pound of weight loss while dieting without exercise.
Body Mass Index (BMI):
This is a measure of a person's weight relative to their height. Please
be aware this classification has limitations as it does not take frame
size into account.
Total Body Water: Water is
contained in lean body mass. Total body water consists of two
compartments - intracellular water (ICW) and extracellular water (ECW).
It is the amount of water contained in the body and is a measure for
evaluating basic hydration status.
Intracellular Water (ICW): This is a measure of the amount of water
contained within the cell. Healthy cells maintain their integrity and
hold their fluid inside the cell membrane. Water is needed inside the
cell to hold in water-soluble nutrients such as vitamins B and C. The
optimum amount of water that should be inside the cell differs
according to gender and age. As a general rule, 2/3 of your water
should be inside the cell.
Extracellular Water (ECW): This is a measure of the amount of water
outside the cells. This water stores some nutrients and also helps to
remove waste from inside the cell. As a general rule, 1/3 of your water
should be outside the cell.
A low ICW reading may be due to many things including dehydration,
nutritional imbalance, hormonal imbalance or toxicity. Talk with a
wellness consultant to determine if a naturopathic, nutritional or
traditional Chinese medicine consultation would be suitable for you.
Total Body Water/Lean Body Mass: This is the percentage of lean body
mass that is water. Normally about 73% of fat-free mass is water.
TBW/Total Weight: This is the percentage of total weight that is water.
In females, this should be approximately 55% and in males, 60%.
A progressive increase in lean body mass, body cell mass, and phase
angle are associated with increasing physical performance. With the use
of the BIA to monitor key indicators of health and fitness, healthcare
practitioners can develop, monitor and manage diet, nutrition and
exercise programs that lead to improved overall physical condition.
The use of BIA to evaluate the effectiveness of treatment strategies
for various health conditions is widespread. BIA is used in many
studies and clinical trials around the world.