BodyGem Indirect Calorimeter

The BodyGem® indirect calorimeter is a state-of-the-art, handheld device that accurately measures resting metabolic rate (RMR). The BodyGem is easy to use, delivering an RMR measurement quickly and accurately.

The BodyGem

BodyGem gives you important information to help individuals achieve personal weight management and nutrition goals. With each BodyGem comes the BodyGem® Analyzer professional companion software. BodyGem Analyzer assists health and wellness professionals in developing personalized weight management plans and generation of important education reports for each client.

BodyGem Dimensions

5.5 x 5.5 x 11.5 cm ( 2.2 x 2.2 x 4.5 in)

BodyGem Weight:

110 gm ( 4 oz)

Measurement Specifications

RMR Range:
RMR Resolution:
500 to 5000 Kcals/day 
10 Kcals/day
Time: 5-10 minutes

Operating Environment

Relative Humidity
-30 to 3040 meters (-100 to 10,000 feet) 
15° to 30° C ( 59° to 86° F)  
10% to 88% RH Non-condensing

Storage Environment

Relative Humidity
10° to 50° C ( 14° to 122° F)  
5% to 95% RH Non-condensing

Data Port

RS-232 Serial Port


Accuracy / Reliability*                            Â± 99%  /  r = 0.91


There are no user serviceable parts in the BodyGem device, please return to Microlife Medical Home Solutions, Inc. for servicing.

 "The MedGem may be a useful clinical tool when the Delta-Trac indirect calorimeter is not available....5 predictive equations compared to the MedGem measurement found none of the equations had acceptable bias and precision among overweight and obese adults." 

Ziegler et al. 2010


"The portable MedGem may assist research dietitians in determining energy needs of racially diverse populations of middle-aged overweight and obese women."

Spears et al. 2009


"The use of the MedGem may provide clinicians a diagnostic tool for tailoring a nutrition message specific to each client."

McDoniel et al. 2008


"Cardiac output determinations made with the MedGem's measurements of oxygen uptake are clinically acceptable."

Shepherd et al. 2007


 "The MedGem hand-held indirect calorimeter has potential application in clinical evaluations in which typical metabolic carts or other standard methods  are not practical.   

Fields et al. 2006


The MedGem can be used to accurately measure oxygen consumption and  RMR in capacities where a traditional metabolic cart would not be practical or cost-effective.    

Stewart et al. 2005





"The MedGem provides a quick and convenient estimate of RMR in children that  is accurate and reliable, and should facilitate the process of pediatric weight management counseling.     

Nieman et al. 2005

Nutritionists, Exercise Trainers, and other Wellness professionals can provide clients with a more accurate nutritional assessment and individualized weight management program. With BodyGem Analyzer individual measurements can be utilized to develop personalized nutrition & activity plans that promote energy balance literacy and empower client self-management of daily nutrition, exercise, and other health goals.


When should an RMR measurement be taken? Will I get a different RMR measurement if I take a measurement after exercising instead of taking the measurement first thing in the morning?

To obtain an accurate resting metabolic rate (RMR), the measurement should be done at least 4 hours after eating or exercise. The BodyGem® device can be used at other times of the day, but the RMR will be slightly elevated depending on the amount of activity you have done and when you last ate.

How often should I measure my metabolism?

If you are losing weight or participating in a fitness program that includes strength training, we suggest measuring your metabolism approximately every four weeks. Monitoring your RMR will allow you to adjust your daily calorie targets if your metabolism changes. Repeat measurements should be performed at the same time of day under similar conditions.

Can I reuse the mouthpiece?

The mouthpiece is a single-use item. It contains filter material to prevent cross contamination and should be disposed of after each measurement. Always use a new breathing attachment when performing a measurement.

What does the reading on the BodyGem unit mean?

The number that appears on the LCD display of the BodyGem unit is your resting metabolic rate (RMR).  RMR is the number of calories your body burns each day at rest and with little activity. For many people, RMR can represent up to 75 percent of total metabolism. Lifestyle, activity, and exercise make up the rest of total daily calories expended. Your RMR measurement helps determine how many calories you should eat to maintain your weight management and fitness goals.

How accurate is the BodyGem measurement?

The BodyGem unit has been validated against the Douglas Bag method, the gold standard in metabolic measurements. The BodyGem unit is as accurate as the Douglas Bag method for determining RMR. The coefficient of variation for repeated measurement is less than 1%. The BodyGem’s portability makes measuring metabolism possible for most individuals and professionals.

I exercise a lot and my  metabolism has not increased. Why?

Aerobic exercise burns calories during the activity, but doesn’t have a significant effect on increasing your metabolism during the rest of the day. Your metabolism temporarily increases after aerobic exercise while the body cools down, but this calorie burn is relatively low unless the exercise intensity and duration have been high. The calories you burned during aerobic exercise will help you balance the calories you eat.  Strength training burns fewer calories during the exercise, but can increase muscle, which will lead to an increase in metabolism. Muscle is more metabolically active than fat and burns more calories to maintain at rest. Body fat burns very few calories. You will have to do strength training several times a week to increase lean body mass and see the results in your metabolism. Try a combination of aerobic exercise and strength training to get the benefits of both!