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Bioimpedance Analysis is a completely non-invasive tool for measuring your internal body composition. From the findings, you are provided with a full health assessment and the dietary and lifestyle tools you need to improve your general wellbeing, age healthily, increase vitality, and address any specific health concerns.

It is a completely safe, painless and scientifically validated test that was developed to monitor patients in a hospital setting during rehabilitation; and has since been used in several missions in space to monitor changes to astronauts’ muscle tissue and cellular health.

Bioimpedance Analysis can provide information on the following:

  • How much fat and muscle your body consists of
  • The ideal fat to muscle ratio and weight for your frame
  • Hydration levels (both inside and outside the cells)
  • The quality of your muscle tissue
  • Your cellular age
  • Your level of risk for metabolic disease

You will benefit from this anti-ageing test if you want to:

  • Manage your weight effectively
  • Increase muscle tone and fitness
  • Improve your energy levels and minimise fatigue
  • Age healthily (and slowly!)
  • Learn how to support your body nutritionally
  • Gain insight into your body beyond what the mirror tells you

Erin Collins will help interpret and explain the results of the analysis and discuss possible lifestyle options for maintaining or attaining optimal health and wellbeing. Recommendations may include dietary recommendations, exercise options, nutritional supplementation and herbal medicines.

What is Body Composition?

Body composition is simply the amount of lean body mass and body fat that makes up total body weight. The lean body mass (LBM) includes the bones, muscles, water, connective and organ tissues. Body fat includes both essential and non-essential fat stores. Essential fat includes organs and tissues such as nerves, lungs, liver, brain, and mammary glands. The non-essential fat is primarily within adipose tissue.

Why do I need my body composition analyzed?

Total weight on is own is of little importance and far too many people base their diet regimen on what they see on the bathroom scale. Irrespective of total weight, if lean and fat proportions are within established recommended limits then one has a significantly reduced risk of suffering from many health problems associated with being seriously overweight or obese:

Equally serious, however, is the problem of having too little body fat since adipose tissue is vital for normal organ function. The dramatic increase in anorexia nervosa, bulimia and a “fear of obesity” over the last decade demands an awareness of correct body composition.

It is clear then that the total body weight does not provide an accurate reflection of an individual’s state of health. A weight-lifter may be classified as seriously over-weight, according to standard height/weight tables but yet have perfect body composition. Conversely, a person may have a “normal” weight according to standard tables and yet be over-fat.

If you are embarking on a weight loss program, it is essential that you are aware of your Body Composition.

Often, diets will result in loss of mostly lean body tissue and water. By tracking your body fat, you can closely monitor what body composition changes are actually happening. Just knowing how many pounds you have lost is insufficient. The goal of any weight control program needs to involve adjusting a person’s exercise and dietary habits to reach the ideal percentage of body fat.

How is it measured?

The Hobart Naturopath clinic utilises the Bioelectrical Impedance Analysis (BIA) method to measure body fat composition.

The physical principle behind the BIA technique is that the body’s lean compartment, comprising approximately 60-75% electrolytic water, conducts electricity far better than the body’s fat compartment, which is very low in body water content (between 5-10%). These two compartments have, therefore, very different impedance (or resistance) values to a high-frequency electrical signal. The signal impedance measurement reflects the degree of resistance to the flow of current in the body, water being a good conductor but fat a bad conductor.

So, this technique is essentially an index of total body water, from which fat-free mass is estimated.

What is the procedure for the BIA?

You will remove any metallic objects that you may be wearing. You will remove your shoes and socks only. You will stand on the test scales while a battery-generated signal is passed through the body and an impedance value is produced.

This value, together with other details of age, height, weight, and gender are used to analyse the data and within 20 seconds produces a comprehensive personal body composition statistical analysis.

Measurement under the changing conditions of temperature and total body water distribution or blood flow volume of extremities due to exercising, taking a bath, etc., affects the measurement result since the electric resistance in the body also changes.

Therefore, it is recommended to conduct the analysis under the following conditions:

  1. 3 hours have passed after getting up and normal lifestyle activities are carried out during this period.
  2. 3 hours or more have passed after eating. (For 2 – 3 hours after eating, the impedance has a tendency to decrease.)
  3. 12 hours or more have passed sinc vigorous exercise. (The tendency toward changes in impedance is not stable depending on the type and rigorousness of the exercise.)
  4. If possible urinate before taking measurement.
  5. For repeated measurements, measure at the same hour if possible.
  6. The analysis is not accurate during the menstrual period
  7. Alcohol not be taken 12 hours before the test

Is it safe?

The BIA Method is very safe. It sends an extremely weak electrical current - (50 kHz/500 micro Amp) that is painless, safe, and non-detectable. While there is no historical or clinical evidence that pacemakers are affected by bioimpedance testing, pacemaker manufacturers recommend that persons with pacemakers should avoid external electrical currents.

Is it accurate?

As long as the BIA Testing Conditions are maintained, BIA is accurate and highly reproducible. This is unlike the skinfold caliper where the skill of the technician, the accuracy of the calipers, the placement of the caliper during measurement, and the individual’s fat patterns can cause errors greater than 5%.

In clients who have varying body water contents, BIA may not give an accurate body fat measurement. However, BIA is still a good method for monitoring changes in body fat in these individuals. Clients who may have varying body water contents include: the elderly, children, body-builders, athletes, individuals with illness, individuals experiencing swelling, individuals who have osteoporosis, women who are pregnant, or individuals undergoing dialysis.

In a study published in the Journal of the American Diet Association, the foot-to-foot bioelectrical impedance analysis (BIA) was shown to be as accurate as the traditional foot-to-hand analysis.

How does it work?

Bioelectrical Impedance Analysis (BIA) operates by passing small electrical signals through the body via the footplate electrodes. The current is induced and the voltage drop measured via four metallic footplates situated within a conventional weighing scale. The heels of the feet are placed on two of the plates while the toes are placed on the other two plates, which act as separate electrodes. The electrical current is carried via the anterior plate (toes) and the voltage drop is measured across the posterior electrode (heel). The conducting ability of bodies tissues is then used to calculate the amount of fat mass, lean mass, bone mass and basal metabolic rate.

The print-out analysis

Print out total body composition readings including:

  • Weight
  • Impedance
  • Fat %
  • Fat Mass
  • Fat Free Mass
  • Total Body Water %
  • Total Body Water Mass
  • Muscle Mass
  • Physique Rating
  • BMR (Basal Metabolic Rate)
  • Metabolic Age
  • Bone Mass
  • Visceral Fat Rating
  • BMI

Fat % / Fat Mass

Fat Mass is the predicted amount of fat in the subject’s body. Fat % is the proportion of Fat Mass to the total body weight.

Body Fat is essential for maintaining healthy skin, hair, body temperature and protecting internal organs. Yet, too much fat can damage your health. Reducing excess levels of body fat has shown to reduce the risk of certain conditions such as high blood pressure, heart disease, type 2 diabetes and cancer.

Fat Free Mass (FFM)

Fat Free Mass is comprised of non-fat components of the human body. Muscle, bone and water are all examples of fat-free mass.

Muscle Mass

The predicted weight of muscle in your body. As you exercise more, your muscle mass increases, which in turn burns more calories.

Total Body Water % (TBW %)

  • Total Body Water Percentage (TBW%) is the total amount of fluid in the body expressed as a % of total weight.
  • Being well hydrated will help concentration levels, sports performance and general well-being.
  • Generally drinking 2 liters of fluid a day will ensure good hydration levels.

The average TBW% ranges for a healthy person are:

  • Female 45 to 60%
  • Male 50 to 65%
  • Children 60-75%

Individuals with a high body fat % may fall below the recommended body water percentage. As body fat is reduced over time the TBW% should gradually improve.

Body Mass Index (BMI)

Body Mass Index is a standardised ratio of weight to height, and is used as a general indicator of health. Your BMI can be calculated by dividing your weight (in kilograms) by the square of your height (in meters)

  • <18.5 = Under Weight
  • 18.5 – 24.9 = Normal Weight
  • 25-29.9 = Overweight
  • 30> = Obese

Note: BMI is influenced by build and muscle mass.

For example, misleading results may be given for:

  • People with high muscle mass (e.g. sportsmen and women)
  • People who suffer from muscular dystrophy or water balance dysfunction
  • Changes in body composition over time

BMI is a good general indicator for population studies but has serious limitations when used for individual analysis.

Bone Mass

  • The predicted weight of bone mineral in your body.
  • It has been proven that increased muscle mass through sport activities promotes stronger healthier bones.

Check for significant changes over time.

Physique Rating

Physique rating assesses muscle and body fat rating into 9 body types.

As your activity level change over time the balance of body fat and muscle will alter which will change the user’s overall physique

Intra Cellular Water

Intracellular Water or Cytosol, is the liquid found inside cells.

Usually 40% of your body weight is intracellular water.

Extra Cellular Water (ECW)

Extracellular Water is the body fluid found outside of the cells.

Approximately 15% of the body weight is extracellular water (this can be split into 10% intracellular liquid between the cells and 5% intravascular liquid in the blood)

Extra Cellular Water/Total Body Water (ECW/TBW %)

  • The percentage of extracellular water in relation to the total body water.
  • Ideally the value should be approximately 40%.
  • Visceral Fat Rating Visceral fat is the fat in the abdominal area surrounding and protecting the vital organs.
  • Ensuring you have a healthy level of visceral fat reduces the risk of certain conditions such as heart disease, high blood pressure and type 2 diabetes.
  • Rating from 1 to 12: Indicates you have a healthy level of visceral fat. Monitor regularly to ensure your rating stays within this range.
  • Rating from 13 to 59: Indicates you have an excess level of visceral fat. Consider making changes in your lifestyle possibly through diet changes and/or increasing exercise.

Basal Metabolic Rate (BMR)

Basal Metabolic Rate is the daily minimum level of energy or calories needed at rest for your body to function effectively.

Increasing muscle mass will directly speed up the metabolic rate. A person with a high BMR can burn more calories at rest than a person with a low BMR.

- = low burn- your body is slow at burning calories

0 = average burn - your body is standard at burning calories

+ = high burn - your body is fast at burning calories


The science

BIA is based on the underlying principle that resistance or impedance to the flow of an electrical current through the body is dependent on three variables: the length of the conductive path, the volume of the conductive material, and

the resistivity of the conductive material. In the human system, only body water, with its dissolved electrolytes, will conduct a current. Hence, using the assumption that the resistivity of the conductive material is constant, and estimating the length of the conductive path from an individual’s height, total body water can be estimated by measuring impedance to the flow of a small current. Assuming that total body water constitutes a fixed percentage of lean mass (usually 73%), body composition can be estimated. Specific prediction equations have been developed to evaluate body composition from height, weight, and impedance

Impedance, resistance and reactance

Impedance is a measure of how a current is slowed or stopped as it passes through a material. The impedance is affected by two factors, resistance and reactance.

Resistance is a measure of the amount of electoral current a substance will stop. Adipose tissue is about 80% fat. Fat is an excellent resistor. Currents flow much better through any body compartment high in water content, including blood, extracellular fluid and muscle tissue.

Reactance is the measure of a material's ability to slow a current. Cell membranes, for example, can store a charge for a short period of time, thus slowing the current. The slowed current is said to "lag" behind the rest of the current. Cell membranes are able to act as capacitors.

Whether a cell membrane acts as a capacitor or a resistor is dependent upon the frequency of the current applied. A low frequency current is stopped by cell membranes. At this point, the membranes are resistors, as no current is conducted through them.

Therefore, at low frequencies below 50 kHz, any current conducted through a body is passing through the extracellular fluids only. This allows the measurement of only extra cellular fluid.

Current with a frequency higher than 50kHz is able to pass through cell membranes. This allows the measurement of impedance of substances inside of cells, as well as outside of cells. Such currents are essential in effectively assessing body composition.

Several factors can influence the impedance:

  • Hydration (overhydration increase conductivity and reduce impedance, giving a low percent body fat reading by BIA). Dehydration will elevate the reading for body fat percentage.
  • Distribution of water: After a subject has lying down for more than a few minus, their fluids tend to "settle." Settling for more than 5-10 may produce false readings.
  • Orientation of tissues: tissues arranged perpendicular to the current will slow the flow as more membranes will have to be crossed. Parallel tissue and current reduce the impedance. Run BIA testing at least 8-12 hours after exercise or drinking alcohol at least two hours after drinking or eating, within 5 minutes of lying down.

Consultation with naturopath and herbalist, Erin Collins or Michael Thomsen,  including the Body Composition Analysis

Make an appointment using our online calendar system

Or contact reception by email or telephone 03 6223 4842