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Weighing In - The Modern Way

Bioelectrical Impedance Analysis and Body Composition

August 1999

A note from The field of medicine is constantly evolving. As a result, parts of this article may be outdated. Please keep this in mind, and be sure to visit other parts of our site for more recent information!

When you weigh yourself, the number on the scale reflects everything that is in and on your body at the time. The scale can't tell the difference between your heavy boots, the keys in your pocket, and the muscles in your body. If you weigh yourself in a doctor's office without any clothes on, the scale still can't tell the difference between how much your muscles and lean tissue weigh and how much your fat weighs. You still get only one number.

So what! If you are not underweight or wasting, and if you are at your ideal body weight, why is it important to know the weight of the different tissues in your body?

Body Composition and HIV

There are three reasons. The first came to light ten years ago when Dr. Donald Kotler discovered that the point of death of a person with AIDS was related to the amount of lean tissue -- also called body cell mass, or BCM in the shorthand of nutritionists -- that person had lost. He found that you won't live for very long if you lose more than 46 percent of your BCM, and that person's death was separate from the illness that may have caused the BCM loss.

The second reason is that we now know that even a small loss of lean tissue may result in the increased possibility of getting an opportunistic infection like PCP, a leading cause of death in PWAs. Looked at from a more positive point of view, a PWA/HIV may stay healthier longer with more BCM. Simply put, work out and build muscles!

The third reason to know the weight of the different tissues in your body is the way that HIV causes people to lose and gain weight. Imagine that you are at your ideal body weight, and then you lose ten pounds. Later you gain the ten pounds back. Aren't you back where you started from?

No. When you are HIV-positive, you lose more muscle and gain back more fat than an uninfected person experiencing the same weight loss or gain measured in pounds and ounces. So, even though you are once again at your ideal body weight, your body composition has changed for the worse.

People with HIV tend to go through several periods of weight loss and gain over the years, and as a result are exchanging muscle for fat. On top of that, we also lose muscle and put on more fat as we age. Thus as people with HIV live longer, they have two agents attacking their lean mass -- HIV and Mother and Father Time.

It is also important to stress that many if not most people are not now and have never been at their ideal body weight. Therefore, it is better to know what your actual weight was before you became infected so that you can measure any weight change more accurately, rather than to measure yourself against a standard that you never fit.

Bioelectrical Impedance Analysis

Fortunately, we now have a better device for weighing ourselves than a scale and a better way to determine what we should weigh than ideal body weight charts. It is the BIA, Bioelectrical Impedance Analysis, a machine that "weighs" each of the different kinds of tissue in your body. It measures the amount of muscle and other lean tissue, like your organs, and the amount of fat and water in your body. It tells you if the water you have is in the right place. It also measures the phase angle, which can be described as the "strength" of your cells and is one of the best predictors of survival in HIV disease.

It is best to get a BIA done every three months or so to see how you are doing. It will help you see what you have to do, such as exercise more or drink more water, or show you the positive results of the hard work you've been doing. A good way to use the BIA is to have the first one done right after you test positive. That test will act as a baseline for all future tests to be measured against. Another way is to have a BIA done just before you start an exercise and/or supplement program. It is great to see the improvement on paper in only a few months.

Using the BIA Machine

The BIA itself is a very simple test that can be performed almost anywhere by a doctor, nurse, nutritionist, or other healthcare provider. At the Momentum AIDS Project, where I work, we have been using the BIA for the past two and a half years. We regularly perform the test at each of our twelve programs in four of New York City's 's five boroughs, and we give demonstrations of the technique at many AIDS service organizations in the New York area. The unit we use, the RJL BIA, is run by a battery. Our laptop, which is loaded with the needed software, is also battery driven. We need an electrical outlet to run the portable printer we bring so that the results can be printed out immediately. We also bring a scale with us if there isn't one on site.

The person being tested lies down and two electrodes are attached to his or her right hand and two to the right foot. The BIA has four clips that are then attached to the electrodes. To ensure accuracy from person to person to person and from test to test, it is important that the person administering the test place the electrodes and the leads exactly the same way each time. The more accurate the information that is put in, the more accurate the results that come out will be. BIA results are independent of race or disease.

When the unit is turned on two measurements, the Resistance and the Reactance, appear on the unit's display screen. These measurements, along with the person's age, gender, height, weight, body type (normal, obese, or heavily muscled), and patient type (normal, renal, HIV, cancer, or other), are typed into the computer and, as if by magic, the results appear on the screen.

The results are divided into two main categories, Fluid Assessment and Nutrition Assessment. Two other measurements are given as well, the Phase Angle and Basal Metabolism.

BIA Results

Fluid Assessment has four measurements: Status indicates whether you are dehydrated (not enough water), euhydrated (the right amount of water), or edemic (too much water in the wrong places). Total Body Water is simply a measurement of all the water in your body. Intracellular Water is the water inside the cells of your lean tissue, and Extracellular Water is the water found outside your cells and your blood plasma. After air, water is the most important nutrient we ingest.

Nutrition Assessment also has four measurements. Body Cell Mass is the most active metabolic tissue in our bodies. I call it the fire-breathing tissue. This is the tissue that does the work in our bodies. It uses oxygen to burn glucose. It is the home of the intracellular water. It is loaded with potassium. It is our own internal combustion engine. BCM is the tissue that helps to keep you healthy. It is the tissue you want to build up when you lift weights and do other kinds of resistance exercise. It makes walking up stairs easier and makes you happy when you look in the mirror. Organs such as your heart, liver, and GI tract are another section of BCM. The Extracellular Tissue is the home of extracellular water and the place where you find sodium, chlorides, and calcium. It is made up of the skeleton, tendons, ligaments, plasma, and other tissues. Its primary purpose is transport and support. Fat-Free Mass is the sum of the body cell mass and the extracellular tissue. Fat Mass is all the fat in the body. Contrary to what most people believe fat contains very little water.

Phase Angle, the next measurement, is one of the best predictors of long-range survival in HIV disease. The last measurement, Basal Metabolism, is the amount of energy (calories) you would need to keep your body going if you didn't do anything but lie in bed all day and stare at the ceiling.

The Momentum Experience

We began using the BIA at the Momentum AIDS Project during the late fall of 1996. We had to establish some guidelines since, as far as we knew, we were the first community-based organization to use this new technology. We read quite a few scientific papers, but all of the work had been done in clinical trial settings and was not applicable to our situation.

What we did was to set up a pilot program that ran for four months. During that time we asked for volunteers from our staff, client leaders, and board of directors. Anyone who could lie still for five minutes had a BIA done, and we hoped that we wouldn't get any bad readings that we would have to report to our colleagues and members. Even though I was thoroughly trained in the use of this new technology and had my trainer, Gary Lustberg, present the BIA to a graduate class I was teaching at Hunter College, I was nervous about what I might find out about people I really cared for, my clients. Now, after having completed 669 BIA tests and counseling sessions, I can honestly say that I am still nervous!

In the two and one half years that we have been using the BIA, several things have become evident. First and foremost is the importance of counseling. Both the people administering the test and the PWAs taking it need to be committed to improving our eating, exercise, drug use, and overall lifestyle habits, or all the objective technology in the world won't make a bit of difference. A counselor who goes out for a smoke after a BIA session is missing the point, and clients won't miss the discrepancy between talk and action. On the other hand, a report on paper very often opens the door to discussions that might not have taken place otherwise. When your report says that you are dehydrated , the logical question for you and your counselor is, Why? The answer can open the door to the solution. Without the BIA, the question wouldn't have been asked.

I think the second and subsequent BIA tests are even more important than the first since changes in the report printed on paper seem to make a bigger impression than a counselor's advice alone. The second test also opens up new areas of concern and show how your efforts -- or lack of efforts -- make a big difference.

The counselor may also use Fluid and Nutritional Analysis History Graphs and a Fluid and Nutritional Analysis Table to identify problems and possible solutions. For, example, if you have been eating well and exercising, drinking water, and taking your meds religiously but the BIA shows that your body cell mass has not been going up, what do you do -- blame it on HIV? No. The missing element may very well be low testosterone, since the test shows that everything else is okay. Instead of getting frustrated and giving up, get your testosterone checked!

The issue of weight gain and weight loss takes on new meaning when looked at in the light of body composition. For example, a Momentum member started an exercise program but had not had a BIA done since his baseline test in October 1997. His second test, in March 1999, showed a five-pound weight increase, but only one pound of it was body cell mass, the fire-breathing tissue. Two and a half pounds was fat and one and a half pounds was extracellular tissue. The last test he did in June 1999 showed a six-pound weight loss over his March results!

On the surface, this weight loss doesn't look good until you analyze the results. He gained another half pound of body cell mass, and naturally his intracellular water went up. He lost four and one half pounds of fat. Since his eighteen percent of fat is well within the norm for men, ten to twenty percent or so, depending on whose numbers you like to use, he seems to be in better shape than he was before. Other factors to consider are his Phase Angle, which continued to go up; his Basal Metabolism, which is very stable; and his current weight, which is closer to his pre-HIV weight than his March 1999 weight was.

Another man had gained five pounds in the six months since his first BIA was done. In pre-BIA days, any weight gain was considered a positive event. Now, however, the second test showed some negative movement -- all the weight gained was fat. Some body cell mass was lost, which meant that the increase in fat was even more than five pounds, since the BCM that was lost was replaced by fat. His intracellular water and his phase angle had gone down. As if things weren't bad enough for this gentleman, the crack pipe was calling out more and more often. His eating habits were reduced to snacking on junk food in front of the TV. He ate real food only when he came to one of Momentum's meal sites.

Checking out the red flags that this PWA's BIA had raised, the Momentum counselor learned that our client's friend of almost thirty years was in the hospital with no hope of getting out alive. In the face of the inevitable death of his friend, life itself seemed pointless. This was no time for a lecture on the nutritional value of broccoli! Instead, a lot of talk, time, support, the offer of off-hour staff telephone numbers, and a referral to a therapist helped get the client through this difficult time. You will not find this kind of thing listed in the literature as one of the advantages of using a BIA, but in reality it's more common than you might think.

Strengths and Weaknesses

The BIA is not the answer to all problems in the area of HIV disease and body composition. It has shortcomings. It cannot as yet determine whether or not someone has lipodystrophy, or tell the difference between a woman with low body fat and big breasts and a fat woman with small breasts. In other words, it can tell us how much body fat a person has, but not where the fat is or how it is distributed. I am sure I am not the only person who has noticed this problem, however, and I am also sure that the scientists at RJL, the manufacturer of the unit we use at Momentum, are working on the problem.

Another question concerns people who are severely constipated. They are generally dehydrated and their total body water is low, but is the BIA dealing with the mass of waste properly?

The BIA helps to confirm what we already know. Counseling works. At Momentum, nutrition and health education, harm reduction, and social work counseling really work. The 156 repeat tests that we have done confirm this.

I am not saying that all the tests show improvement all the time. They don't. But having another marker to monitor your lifestyle can be a very powerful incentive to do better. This is especially true since we run our BIA tests and counseling sessions at our ten meal sites around New York City. After your test, you can sit down and eat your vegetables with conviction.

Some of our clients have told me that they like to bring their reports to their healthcare providers since it gives them an active part and some control in their healthcare. Like all people, they like to show off the good results to their friends. So we try to make sure that you leave after your counseling session with a copy of your BIA results.

I know that people who are on a mission or a run -- that is, using drugs heavily -- are probably avoiding the BIA at all costs. But I also know that when they come back to earth they want to see what damage they have done and get back on the road to living. Telling someone that dope or alcohol is physically destructive is not nearly as effective as showing a declining phase angle or a loss of body cell mass that occurred after a binge. The BIA report has more of an impact because it is free of any negative moral judgment.

Take a few minutes and get the test. If you don't know where to get a BIA, ask your primary healthcare provider or your local AIDS service organization.

Edwin Krales is Coordinator of Nutrition and Outreach at the Momentum AIDS Project.

Photo by John Gomez

Back to the August 1999 Issue of Body Positive Magazine

A note from The field of medicine is constantly evolving. As a result, parts of this article may be outdated. Please keep this in mind, and be sure to visit other parts of our site for more recent information!

This article was provided by Body Positive. It is a part of the publication Body Positive.
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