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BOD POD® Gold Standard Body Composition Tracking System

Measurement in BOD PODThe Institute for Clinical and Translational Science at The University of Iowa announces availability of the BOD POD® Gold Standard Body Composition Tracking System (COSMED USA, Inc.; Concord, CA to measure body fat. This fast, safe, and radiation-free machine measures adults and children (5 years and older) including those who are disabled, elderly, athletes, and/or weighing up to 550 lbs. The BOD POD® is used at research units, hospitals, fitness centers, military installations, and sports teams around the country and internationally. For more information, see our Frequently Asked Questions below or contact Kate Seemuth or call 319.353.6250.


What is a BOD POD®?

Getting set up in the BOD PODThe BOD POD® is an egg-shaped, fiberglass Air Displacement Plethysmograph that measures body volume using a patented air displacement process. BOD POD® development was supported by several NIH Small Business Innovative Research (SBIR) grants. First introduced in 1994, the BOD POD® is now used at the NIH Clinical Center and other research centers across the US and internationally.


How does the BOD POD® determine body composition?

Photo of boy getting measuredThe principle underlying the BOD POD® is whole body densitometry: 

Body density (Db) = mass / volume 

Mass is obtained by weighing the individual on an accurate scale included with the BOD POD®. Volume is determined using the BOD POD’s egg-shaped air displacement plethysmograph. Db can then be converted to percent body fat using one of several population-specific conversion formulas or used in combination with other body composition measurements (eg, mineral and total body water) to calculate percent body fat.


How accurate is the BOD POD®?

Graphic of BOD POD accuracyThe BOD POD® has been shown to accurately and reliably measure the volume of inanimate objects (Dempster and Aitkens, 1995) and the percent body fat of humans when compared with values obtained from hydrodensitometry (ie, under water weighing) (McCrory et al, 1995). Numerous published studies have compared the BOD POD® with other body composition methods in various population groups. The BOD POD® and hydrodensitometry are based on a body composition model that divides the body into two compartments: fat and fat-free. Therefore, the accuracy of these methods depends on how well the assumptions of this model are met:

  • Assigned densities of fat and fat-free body are accurate
  • Proportions of water, mineral, and protein are constant within and between individuals
  • Individuals differ from the reference body only in amount of fat

Three- or Four-Component Molecular models which consider the variability of water or mineral content of the fat-free body, or both, and are generally thought to provide more accurate estimates of body fat than 2-component models, especially when one of the assumptions of the 2-component model might be violated. The table below compares features of different models (Heyward and Wagner, 2004).

Body Composition Measurements Used  Measurements Used
Title Description BOD POD DXA Total Body Water
 2-Component Molecular Level BW = fat + Fat free body     
 3-Component Tissue Level BW = bone + bone-free lean tissue + fat       
 3-Component Molecular Level (accounts for variability in mineral content of fat-free body) BW = fat + mineral +(water and protein combined)       
 3-Component Molecular Level (accounts for variability in hydration) BW = fat + water + (mineral and protein combined)      
4-Component Molecular Level (recommended when hydration and mineral content of the body may vary greatly)  BW = fat + water + bone mineral + protein       

*BW = body weight


1. Dempster P and Aitkens S. A new air displacement method for the determination of human body composition. Med Sci Sports Exerc 27:1692-1697, 1995.

2. Heyward VH and Wagner DR. Applied Body Composition Assessment 2nd ed. 2004: 6-12.

3. McCrory MA, Gomez TD, Bernauer EM, Mole PA. Evaluation of a new air displacement plethysmograph for measuring human body composition. Med Sci Sports Exerc 27:1686-1691, 1995.

What preparation is expected of individuals prior to a BOD POD® test?

Prior to the test, individuals will be asked to:

  • Not eat, drink or exercise for at least two hours prior to the test
  • Bring a form-fitting Lycra® or Spandex® swimsuit or single-layer compression shorts and/or lightweight jog bra (without padding or wires)

Why do individuals need to wear a swimsuit if they don’t get wet during the test?

The surface area of clothing and hair will significantly change the body volume measurement. To minimize this effect, individuals are asked to wear a form-fitting Speedo® or other Lycra®/spandex-type swimsuit and swim cap during the test.

Can an individual be measured if they don’t have a swimsuit?

Yes. Individuals can also wear single-layer compression shorts and, if female, a jog bra without padding or wires. If this clothing is not available, individuals can wear any form-fitting clothing that will not trap air such as briefs and a bra without padding or underwires For more information about suitable attire, contact Kate Seemuth.

Because of its egg-shape, the BOD POD® has a generous interior and can accommodate large individuals. The BOD POD® has been used to measure the body composition of morbidly obese individuals having a body mass index of 40 to 58. Children as well as professional athletes and sumo wrestlers have been measured with the BOD POD®.

Will my study participants feel uncomfortable wearing a swimsuit?

We have not found this to be an issue among the individuals we have measured. However, we do understand this concern and have designed our body composition room and measurement procedures with privacy in mind. The body composition measurement is made in a private room. Individuals have a curtained area within the room where they can change clothes and the technician may leave the room to allow for additional privacy. Participants are then weighed behind the privacy curtain so they are not visible to the technician. If they wish, participants can don a robe to walk the few steps to the BOD POD® chamber. Once individuals are seated in the chamber the robe is removed. The robe is then given back to the participant when they are ready to leave the chamber

What does a person experience during a BOD POD® test?

When individuals arrive for the test they:

  • Void, if needed
  • Change into their form-fitting swimsuit
  • Remove socks, shoes, jewelry and eyeglasses
  • Wear the swim cap provided

Child sitting in BOD PODAfter the person is weighed, they will be asked to enter the BOD POD® chamber, sit quietly (no talking, laughing or moving), relax, and breathe normally. When the person is ready to begin the test, the technician closes the BOD POD® door and begins the first measurement which lasts about one minute. During the test the person may feel air movement and hear the sound of valves opening and closing to move the air. Some people also feel a slight pressure change similar to that of moving from the first to second floor in an elevator. When the first measurement is finished, the technician opens the door and speaks with the person. Then the technician closes the door and conducts a second measurement. If the two measurements are not similar, the technician performs a third measurement.

Finally, a lung volume measurement is conducted to correct for the increased compressibility of air in the lungs. While sitting in the BOD POD® with the door closed, the individual breathes into a plastic tube connected to the chamber. The technician coaches the subject on breathing through the tube using only the mouth (that is, with nose clamped shut) and puffing into the tube as if laughing. 

View a demonstration test (running time: 4 min 26 sec)


How long does the test take?

The entire visit takes approximately 20 minutes. Actual time the individual is enclosed in the chamber for the volume determination is about five minutes (two to three 50-second measurement periods and another one to two minutes for the lung volume measurement).


What type of data does the BOD POD® generate?

The BOD POD® provides the following information. Data can be sent to investigators electronically and/or printed in a format suitable for patients.

  • Body Mass (weight)
  • Fat mass and percent fat
  • Fat free mass and percent fat-free mass
  • Body volume
  • Body density
  • Thoracic gas volume


If a person is uncomfortable in enclosed spaces, can they be measured in the BOD POD®?

Close up of BOD PODYes. The BOD POD® has a large window so the person inside can see and hear the technician during the test. This design helps most individuals feel comfortable inside the chamber. However, if the person is uncomfortable at any time they can ask the technician to stop the test or they can press and hold a button at their knee while pushing to open the door.





What types of individuals can be measured in the BOD POD®?

people who can use the BOD POD

  • Children five years and older*
  • Adults
  • Athletes
  • Obese individuals
  • Disabled individuals 

Because of its egg-shape, the BOD POD® has a generous interior and can accommodate large individuals. The BOD POD® has been used to measure the body composition of morbidly obese individuals having a body mass index of 40 to 58. Children as well as professional athletes and sumo wrestlers have been measured with the BOD POD®.

* Toddlers and young children have difficulty sitting quietly during the test so a Pediatric Option Accessory can be purchased for use when measuring toddlers. 

How do I include the BOD POD® in my grant application?

Please contact the Bionutrition Manager if you plan to include the BOD POD® in your grant application. She can provide you with a description of the BOD POD® for the protocol and consent form as well as a cost estimate to include in your budget.

What is the cost and availability of BOD POD® measurements?

The BOD POD® is available Monday through Friday between 9am and 4pm and should be scheduled with the Bionutrition Manager at least 24 hours in advance. Cost for the test includes a swimcap the subject wears during the test, a disposable breathing tube and filter for the lung volume (thoracic gas volume) measurement and labor costs. 
Subjects will need to provide their own form-fitting Speedo® or Lycra®/spandex-type swimsuit or single-layer compression shorts (without padding) and jog bra (without padding or wires) to wear during the measurement.


Is the BOD POD® available for educational use?

Yes. Contact Kate Seemuth for availability and pricing.


I’d like to have my body composition measured. Do you measure the public?

No, we regret that we currently do not. However, please check back as we will be offering public measurements later this year.  In the meantime, please visit the COSMED website for locations of other testing centers that serve the public.


Medicine and nutrition are ever-changing sciences. As new research and clinical experience broadens our knowledge, changes in nutrition recommendations, treatment and drug therapy are required. The authors have checked with sources believed to be reliable in their efforts to provide information that is complete and generally in accord with the standards accepted at the time of publication. However, in view of the possibility of human error or changes in medical sciences, neither the authors nor the University of Iowa nor any other party who has been involved in the preparation or publication of this work warrants that the information contained herein is in every respect accurate or complete, and they are not responsible for any errors or omissions or for the results obtained from the use of such information. Readers are encouraged to confirm the information contained herein with other sources.