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Body Composition
Every person is composed of the same basic elements, bone, muscle, organs, and fat.
The study of body composition looks at the differences for these basic elements in a particular
person.
Body composition analysis is one of the best indicators of overall health as determined by a
person’s percentage of fat and lean mass.
Two people who weigh the same amount but whose height or muscle tissue differ do not have
the same body composition. For example, a muscular athlete who is 6’2” and weighs 220 pounds
will have more lean mass (muscle, water, bone, and internal organs) than someone who weighs
220 pounds, but it only 5’6” and does not exercise regularly.
Some fat is necessary for overall health because it plays an important role in protecting internal
organs, provides energy and regulates the hormones that perform various functions in body
regulation.
Excess fat, however, has been linked to a number of health problems such as increased risk for
diseases such as cancer, diabetes and heart disease.
Body composition tests are designed to give you a “whole picture” of your body.
This information is useful to help to develop nutrition and exercise programs which will best
benefit the individual. The body composition tests below are just some of the tools the medical
community uses today.
Body Mass Index
A BMI of 19–24 is considered normal.
BMIs in the normal range are associated with the lowest rates of illness and death.
A BMI of 25–29 is defined as overweight.
A BMI of 30 is defined as obese, which translates to about 30 extra pounds, depending
on your height.
These definitions of overweight and obesity were established after several studies
examined the BMIs of millions of people and correlated them with rates of illness and
death.
Higher BMIs are associated with progressively higher rates of illness and death.
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Even though BMI is very useful, looking at these numbers alone can be somewhat
deceptive. The "normal" range in the BMI table covers a lot of ground. A person at the
lower end of the spectrum could gain a significant amount of weight, which in itself is a
risk factor for disease, and still remain in healthy territory. For example, a 5'6", 130pound woman with a BMI of 21 could gain 20 pounds and still keep her BMI under 25.
BMI is a calculation based on height and weight, and it is not gender-specific in adults. BMI
does not directly measure percentage of body fat, but it is a more accurate indicator of
overweight and obesity than relying on weight alone.
BMI is calculated by dividing a person’s weight in kilograms by height in meters squared. The
mathematical formula is “weight (kg)/height (m²).”
To determine BMI using pounds and inches, multiply weight in pounds by 704.5,* divide the
result by height in inches, and then divide that result by height in inches a second time. (You can
also use the BMI calculator at www.nhlbisupport.com/bmi or check the chart below.)
Conditions affected by cardiovascular fitness:
Blood Cholesterol Levels
Cholesterol is a waxy substance produced by the liver or consumed in certain
foods. It is needed by the body, and the liver makes enough for the body's needs.
When there is too much cholesterol in the body—because of diet and the rate at
which the cholesterol is processed—it is deposited in arteries, including those of
the heart. This can lead to narrowing of the arteries, heart disease, and other
complications.
Some cholesterol is often termed "good," and some often termed "bad." A higher
level of high–density lipoprotein cholesterol, or HDL, is considered "good," and
gives some protection against heart disease. Higher levels of low–density
lipoprotein, or LDL, are considered " bad" and can lead to heart disease. A
lipoprotein profile can be done to measure several different forms of cholesterol,
as well as triglycerides (another kind of fat) in the blood.
High Blood Pressure
High blood pressure is another major risk factor for heart disease. It is a condition
where the pressure of the blood in the arteries is too high. There are often no
symptoms to signal high blood pressure. Lowering blood pressure by changes in
lifestyle or by medication can lower the risk of heart disease and heart attack.
Diabetes Mellitus
Diabetes also increases a person's risk for heart disease. With diabetes, the
body either doesn't make enough insulin, can't use its own insulin as well as it
should, or both. This causes sugars to build up in the blood. About three–
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quarters of people with diabetes die of some form of heart or blood vessel
disease. For people with diabetes, it is important to work with a healthcare
provider to help in managing it and controlling other risk factors.
Behavioral Factors
Tobacco Use
Tobacco use increases the risk of heart disease and heart attack. Cigarette
smoking promotes atherosclerosis and increases the levels of blood clotting
factors, such as fibrinogen. Also, nicotine raises blood pressure, and carbon
monoxide reduces the amount of oxygen that blood can carry. Exposure to other
people's smoke can increase the risk of heart disease even for nonsmokers.
Diet
Several aspects of peoples' dietary patterns have been linked to heart disease
and related conditions. These include diets high in saturated fats and cholesterol,
which raise blood cholesterol levels and promote atherosclerosis. High salt or
sodium in the diet causes raised blood pressure levels.
Physical Inactivity
Physical inactivity is related to the development of heart disease. It also can
impact other risk factors, including obesity, high blood pressure, high
triglycerides, a low level of HDL (good) cholesterol, and diabetes. Regular
physical activity can improve risk factor levels.
Obesity
Obesity is excess body fat. It is linked to higher LDL (bad) cholesterol and
triglyceride levels and to lower HDL (good) cholesterol, high blood pressure, and
diabetes.
Alcohol
Excessive alcohol use leads to an increase in blood pressure, and increases the
risk for heart disease. It also increases blood levels of triglycerides which
contributes to atherosclerosis.
Other Factors
Heredity
Heart disease can run in the family. Genetic factors likely play some role in high
blood pressure, heart disease, and other vascular conditions. However, it is also
likely that people with a family history of heart disease share common
environments and risk factors that increase their risk.