The BOD POD technology is fundamentally the same as underwater (hydrostatic) weighing, but uses air instead of water. The BOD POD measures the volume of air a person's body displaces while sitting inside a comfortable chamber, rather than measuring how much water their body displaces when dunked in a tank. By using air instead of water, the BOD POD offers a fast, safe, and easy-to-use tool for measuring body composition, without sacrificing accuracy.
Since it is based on the same whole-body measurement principle as hydrostatic weighing, the BOD POD first measures the subject's mass and volume. From these measurements, whole-body density is determined. Using this data, body fat and lean mass can then be calculated.
The BOD POD itself is a dual-chambered, fiberglass plethysmograph that determines body volume by measuring changes in pressure within a closed chamber. The front, or test chamber, has a seat that forms a common wall separating it from the rear, or reference chamber. The door to the front chamber is secured by a series of magnets during the brief data collection period. The BOD POD also has a large acrylic window, providing the subject with a wide field of view, making the test process a comfortable and enjoyable one.
BOD POD FAQ´s
How accurate is the BOD POD?
Research studies at major universities established the outstanding accuracy, safety and speed of the BOD POD. Before the BOD POD, the most accepted method was underwater weighing (the “dunk tank”). When comparing the two methods, the BOD POD and underwater weighing often produce identical results. Many top scientists consider the BOD POD to be even more accurate than underwater weighing because testing with the BOD POD is so easy.
The general error range of the BOD POD is 1-2% (the same as hydrostatic weighing).
How does the BOD POD measure body composition?
The BOD POD system measures body composition by determining body volume and body weight. Once those two variables are determined, body density can be computed and inserted into an equation to provide percent fat measurements. Body weight is easily determined by the use of an accurate scale. Body volume is determined by applying the gas law (p1V1=p2V2), an expansion of Boyle´s Law, pV=c. The BOD POD measures volume by monitoring changes in pressure within a closed chamber. These pressure changes are achieved by oscillating a speaker mounted between the front testing chamber and a rear reference chamber, which causes complementary pressure changes in each chamber. The pressure changes are very small and are not noticed by the individual being tested.
Three measurements are performed to determine body volume. The volume of the subject chamber while empty is the first measurement taken by the BOD POD. The second measurement is the volume of the subject chamber with the subject inside. By subtraction, the volume of the subject is determined. Combined with the measurement of mass, the subject´s density is determined and subsequently their body composition is determined.
Why is it important to wear proper clothing?
The BOD POD takes very accurate measurements of your weight and volume (the size of your body). Anything that isn´t “you” – including clothing, jewelry, or eyeglasses – can produce inaccurate results. This is why it´s VERY IMPORTANT you wear minimal, form-fitting clothing such as a lycra or Spandex® swimsuit. Single-layer compression shorts and/or lightweight jog bras are also acceptable clothing (without padding or wires).
A swim cap must also be worn to compress any air pockets within the hair.
How long does a BOD POD test take?
A complete test, including printed results, can be accomplished in about 5 minutes.
What can I expect during a BOD POD test?
Testing in the BOD POD is quick and easy. The process only requires that the person being tested sits quietly in the BOD POD for the brief measurement period (no talking or laughing). You may hear sounds relating to valves opening and closing or the hum of a fan during the procedure. However, no pressure changes will be felt and difficult breathing maneuvers are not required.
How big of a person can fit in the BOD POD?
The BOD POD is designed to accommodate a wide variety of human shapes and sizes. With its generous-sized interior and oversized window, NFL and NBA teams, sumo wrestlers, and people weighing up to 500 lbs. use the BOD POD routinely.
Can I test right after exercising?
No, you should wait at least two hours after exercising. The person being tested in the BOD POD should always be in a completely relaxed state.
What size area is needed to accommodate a BOD POD system?
The recommended minimum area needed for the BOD POD is 8 feet long by 8 feet wide. This size area will provide enough space for the BOD POD, its components, and allow sufficient room for the subject to enter and exit the BOD POD.
Where can I find out if there is a BOD POD testing facility in my area?
For information about the nearest BOD POD to you, call 1-800-4 BOD POD, or send an email to
lmi@bodpod.com. Be sure to indicate the city and state you live in.
