Chapter 6: Body Composition

Pear

(Females) fat storage in the hips, buttocks & thighs

Amenorrhea

(In females) absent or infrequent menstruation, sometimes related to low levels of body fat & excessive quantities of intensity of exercise

Apple

(Males) fat storage in the abdominal area and upper regions of the body (excess fat can lead to high bp, diabetes, early-onset heart disease, stroke, certain cancers, & mortality)

Underwater Weighing

(one of the most accurate) weight is measure on land and water, those who weigh more float more easily than those who are leaner

What does amount of fat depend on?

- age - sex - metabolism - diet - physical activity - exercise

1 kg of body fat =

7700 calories

Autopsy

dissection & chemical analysis of body, the only method for directly measure the percentage of body weight that is fat

Total body electrical conductivity (TOBEC)

estimates lean body mass by passing a body through a magnetic field.

Essential Fat

fat incorporated in various tissues of the body; critical for normal body functioning

Visceral (intra-abdominal) fat

fat located around major organs

Subcutaneous Fat

fat located under the skin

Body fat

incorporated into the nerves, brain, heart, lungs, liver, mammary glands, & other organs & tissues

Advanced Techniques

DEXA & TOBEC

Amount of Fat in Men and Women

Essential fat makes up 3-5% of total body weight in men and 8-12% in women. The percentage is higher in women due to fat deposits in the breasts, uterus, and other gender-specific sites.

Why could BMI be inaccurate?

It doesn't distinguish b/w fat weight & fat-free weight. It is not useful for tracking changes in body composition- gains in muscle & losses of fat, and differences in gender ex. weight trainers, person with short stature, an althete should not use BMI

Metabolic Syndrome

a cluster of symptoms present in many overweight & obese people that greatly increases their risk of heart disease, diabetes, & other chronic illnesses; symptoms include insulin resistance, abnormal blood fats, abdominal fat deposition, type 2 diabetes, high bp, & chronic inflammation

Female Athlete Triad

a condition consisting of three interrelated disorders: abnormal eating patterns (& excessive exercising) followed by lack of menstrual periods (amenorrhea) & decreased bone density (premature osteoporosis)

Body Mass Index (BMI)

a measure of relative body weight correlating highly with more direct measures of body fat, calculated by dividing total body weight (in kg) by the square of body height (in metres) BMI b/w 18.5-24.9 is considered healthy BMI below 18.5 is classified as underweight BMI 25 or over is classified as overweight BMI 30 or over is classified as obese

Waist to height ratio

a more accurate measure than waist circumference b/c waist circumferences tend to be higher in taller people, waist should be less than half your height

Caliper

a pressure-sensitive measuring instrument with two jaws that can be adjusted to determine thickness

Waist Circumference

a total waist measurement helps assess if there are any risks of body fat distribution (more than 102 cm for M & more than 88 for F is associated with a significantly increased risk of diseas)

Fat-Free mass

composed of all the body's nonfat tissues: bone, water, muscle, connective tissue, organ tissues, and teeth

Adipose Tissue

connective tissue in which fat is stored

Obesity

severely overweight, characterized by an excess accumulation of body fat; may also be defined in terms of some measure of total body weight or a body mass index of 30 or more

Skinfold Measurements

simple, inexpensive & practical way to assess body composition, typically involves measuring the thickness of skinfolds at several different places on the body. You can sum up the skinfold values as an indirect measure of body fatness.

Body Composition

the body's relative amount of fat and fat-free mass

Percent Body Fat

the percentage of total body weight that is composed of fat

Overweight

total body weight above the recommended range for good health; sometimes defined as body mass index b/w 25 & 29.9, a measure of the proportion of weight to height

Other methods of measuring body fat

underwater weighing (one of the most accurate), skinfold measurements, the Bod Pod, bioelectrical impedance analysis, & dual-energy X-ray absorptiometry

Air Displacement

using a Bod Pod (small chamber containing computerized sensors) that measures body comp by air dispalcement, body density via ratio of weight to body volume, relatively close to hydrostatic weighing

Dual-energy X-ray absorptiometry (DEXA)

works by measuring the tissue absorption of high and low energy X-ray beams

Bioelectrical Impedance Analysis (BIA)

works by sending a small electrical current through the body & measuring the body's resistance to it, the faster the time the less fat you have, have to make sure body has propper amount of water (the lower the resistance, the greater the fat-free mass)