BMI – What Is It?
BMI stands for Body Mass Index, a statistical term derived from height and
weight. It is closely linked to body fat and health outcomes. Over 50 organizations,
including the US Government and the World Health Organization, have adopted BMI
guidelines. BMI is inversely related to fitness, meaning that the higher your BMI, the
less likely you are to be fit. Every time your body analysis monitor reads your weight
and calculates your body fat, it also calculates your BMI. Along with your weight
and your body fat measurements, the BMI reading gives you yet one more tool to
monitor your health and fitness.
Body Water/Hydration Levels
General health standards indicate that one should consume approximately
64 oz of water per day from food and liquids to maintain a healthy level of hydration.
Maintaining a good hydration level will help improve your overall health and general
feeling of well-being. If your hydration levels are lower than average, you should
increase your water intake accordingly.
Body water/hydration level – how is it measured?
The hydration level is measured by using Bioelectric Impedance Analysis (BIA). The
same analysis that is used to calculate your body fat is used to calculate your hydration level. Taking into consideration a user’s age and gender, a calculation is made
that determines the percentage of water.
Please note: It is not recommended to take the hydration measurements in certain
situations, such as following exercise, after drinking a glass of water, or directly prior
to, during or shortly after menstrual cycles. Hydration may not be at normal levels
during these times.
Bone Mass – What Is It?
Bone is a living, growing tissue. During youth, your body makes new bone tissue
faster than it breaks down older bone. In young adulthood, bone mass is at its peak;
after that, bone loss starts to outpace bone growth, and bone mass decreases.
But it’s a long and very slow process that can be slowed down even more through
calcium-rich diets and weight-bearing exercise.
Who should monitor bone mass?
Most people have no need to monitor bone mass, but certain groups – postmenopausal women, men and women with certain diseases, and anyone who takes
medications that affect bone tissue – might want to watch for decreases in bone
mass. The bone mass reading is to be used as guide only. Watch for trends over
time and contact your healthcare provider for a more detailed explanation of the
readings and with any questions or concerns.
Weight and Body Fat
How does it work?
While body fat can be measured in many ways, the method used in your scale
is bioelectrical impedance. This indirect method of determining body fat starts when
a safe and very low electrical current is sent through the lower half of the body.
The electrical current flows more quickly through water and muscle than it will through
bone and fat. The scale measures the speed of the current. Based on this number,
the scale estimates body fat using a multi-step, mathematical formula.
Is it accurate?
Measurements of body fat tend to fluctuate a lot more than simple weighing,
and different methods of estimating body fat yield very different results. Just as
different scales give different results, different body fat analyzers can provide
very different body fat estimates. Even with the same scale the numbers will
vary because:
• Weight loss tends to produce substantial, continuous, and unpredictable changes
in body water content. Because body fat analysis is determined by water content
in the body, results can vary considerably from day to day.
• Hydration status affects body fat results. If you’ve just worked out, there is less
water for the electrical current to flow through. This may result in a higher body
fat result. In the same way, if you measure your body fat after drinking a lot of
fluid, it may appear that body fat is lower than it really is.
• Skin temperature can have an influence also. Measuring body fat in warm humid
weather when skin is moist will yield a different result than if skin is cold and dry.
• As with weight, when your goal is to change body composition it is better to track
trends over time than to use individual daily results.
• Results may not be accurate for persons under the age of 16, or persons with
an elevated body temperature, diabetes or other health conditions.
What you need to know!
• Percent body fat refers to the number of pounds of fat divided by your total body
weight and multiplied by 100.
• During weight loss, percent body fat doesn’t appear to be reduced as quickly
as expected because total weight loss and total body fat are decreasing at the same
time (for a more detailed explanation, see next section).
• Weight loss in the form of body fat and lean tissue (muscle) is common, and
is normal.
• To minimize the loss of lean tissue, include regular physical activity, especially
strength training, in your weight-loss plan.
Why do I lose weight but my body fat percentage doesn’t change much?
Most body fat monitors show body fat as a percentage only. This body fat
monitor shows you not only a percentage but the actual number of body fat
pounds (in fact, this is the measurement you see after your weight is displayed).
Why is that important? When you lose weight, both the numerator (pounds of
body fat) and denominator (total body weight) go down, so when it’s calculated as a
body fat percentage, the number can be small. For example, a person may weigh 200
pounds and have 40% body fat (= 80 pounds of body fat). He/She loses
20 pounds, but the body fat has only dropped 4% to 36%. That 4% of body fat was
16 pounds of fat – a very significant amount! So do not be overly concerned if
you do not see the percentage change quickly as you are losing weight: monitor
the absolute number of body fat pounds lost. Remember, to minimize the loss of
lean tissue, include regular physical activity, especially strength training, in your weightloss plan.