Friday, June 11, 2010

Body Composition Testing

An attendee of one of the recent talks I gave asked me about the accuracy of different ways to measure body fat. In case you'd like an objective measure of your progress, or a baseline so you know where you want to go, body fat measurement is far superior to weighing yourself on a scale or calculating your BMI. Here's the answer I gave her!

The most accurate ways of testing your body composition:

1. Hydrostatic Body Composition testing involves you exhaling all of the air in your lungs, and then being completely submerged underwater. It's a fairly involved process, but remains the gold standard of the industry.

  • Mobile Hydrostatic Body Composition testing that comes to our area occasionally:
  • Sports Basement has been known to host hydrostatic body fat testing. Contact them for possible schedule: Sports Basement, 1177 Kern Ave., Sunnyvale (408) 732-0300

2. DEXA (dual-energy x-ray absorptiometry) scans use x-ray technology to scan the body and identify fat, lean tissue and bone tissue, but because the scans expose you to radiation, I wouldn't recommend them unless you're getting a full body scan for other reasons.

3. Bod Pods work like hydrostatic weighing, but by displacing air instead of water.
They're generally hard to find, since they are usually found at universities or clinical settings, but you can try to find one near you here:

4. Calipers are one of the most common reliable ways to measure body fat. Your skinfold thickness is measured in several standardized spots, and plugged into a formula to calculate your bodyfat percentage. Lange Calipers are the best on the market, and the ones I use. The American Council on Exercise lists the margin of error at 3.5%, but reliability is great if you have the same person re-measure. Besides, you don't just want to know your body fat percentage, right? You want to know that it's going down as you're exercising and eating well!

5. Bioelectrical impedance measures how long it takes an electrical current to travel through your body. They used to use 4 electrodes placed on your fingers and toes, but are now built into many consumer scales and just read the current up one leg and down the other. Since bioelectrical impedance is so variable depending on the amount of water you have in your body at the time of measurement, it's not very accurate at all.

In order to increase the odds of you learning exactly what your exercise program is doing to change your body, I offer circumference measurements as well as using calipers. It's fun to see exactly WHERE your body fat is coming off, AND where your muscle is being added!

Contact me if you'd like to have your body fat measured!

Committed to your health,