Body Composition
● Benefits of exercise
○ Regardless of weight loss
○ Increased VO2max
■ Correlation between heart disease
■ Indicator of other diseases
■ #1 indicator of mortality (after age)
○ Improved blood lipid profile
○ Improved psychological state
○ Decreased risk of obesity related diseases
■ Diabetes
■ Cancer
■ CVD
■ Hypertension
○ Key component of weight maintenance
■ By itself, it is not very effective for weight loss because diet plays a huge
part as well
● Body fat storage
○ Fat is stored in and around organs of the body
■ Ectopic fat = fat inside in the organs
● Don’t want an excess amount of this
○ Fat is stored in a subcutaneous layer just beneath the skin
○ Essential fat
■ Protection of organs
■ Around nerves and cells
■ Energy source
■ Steroid hormones are made from fat
■ Makes myelin
○ % desired fat should be based on
■ Health
■ Attainability
■ Goals
● Techniques for measuring % body fat
○ Relative weight (RW)
■ **not valid — no scientific evidence to back, used by insurance
companies to increase premiums/prices
■ Used tables and charts
■ 10% above a perfect 1:1 ratio of “ideal” weight from table = overweight
■ 20% above = obese
■ RW = weight divided by midpoint for frame from table
○ Body mass index (BMI)
■ BMI = wt/ht^2
■ Uses height and weight to estimate disease risk
■ Also not valid, based on body image/aesthetically pleasing — no scientific
origin (only better than relative weight)slightly
■ Overweight category has the lowest mortality rate
■ Does not take into account body fat/muscle mass/body fat distribution
■ Biggest problem with linkage between mortality and BMI is that
confounding factors are not considered (fitness, stress, family history,
etc…)
○ Hydrodensitometry (UWW)
○ Air displacement plethysmography (BOD POD)
○ Anthropometry (Skinfolds circumferences)
○ Bioelectrical impedance analysis (BIA — total body water)
○ Ultrasound
○ Dual energy xray absorptiometry (DEXA)
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