PHYSIOLOGY OF EXERCISE – PET 3380 REVIEW GUIDE FOR EXAM II Body Composition 1. Be able to differentiate related terminologies a. Abdominal Fat - Subcutaneous and Visceral Fat in the Abdominal Region b. Subcutaneous Fat – Adipose tissue beneath the skin c. Visceral Fat – Adipose tissue within and surrounding thoracic and abdominal cavities d. Body Density – Body mass/Body Volume e. Body Mass Index – Ratio of Body Mass to stature squared = (body mass/stature2) f. Densitometry – Archimedes’ principle of water displacement to estimate whole body density (Hydrostatic weighting, underwater weighing) g. Fat Mass – extractable lipids from adipose and other body tissue h. Fat Free Mass – lipid-free chemicals and tissues: water, muscle, bone, connective tissue and organs i. Lean Body Mass – Fat-Free Mass + essential body fat j. Specific Gravity = (Body mass/[body mass - body weight in water]) k. Stature –Height expressed in metric units 2. Understand composition of the human body and body composition techniques. a. Reference Man is taller and heavier, his skeleton weighs more and he possesses a larger muscle mass and lower body fat content than reference women. i. Possible reasons: lifestyle, biologic and behavioral factors, hormones ii. Reference Man/Women is statistical comparison of thousands of individuals, not necessarily the ideal healthy person b. Body Composition i. Fat – stored 2 ways 1. Essential Fat – fat in heart, lungs, liver, spleen, kidneys, intestines, muscle and lipid-rich tissues of the central nervous system – needed for normal body functions a. Sex-specific Fat – breast/genitals, lower body subcutaneous, intramuscular, etc. 2. Storage Fat – Fat deposits primarily in adipose tissuse a. 83% pure fat, 2% protein, & 15% water b. 12% in men, 15% in women c. Body Composition Techniques i. Old Way – Height to weight table, doesn’t consider %body fat ii. Direct Measurement 1. Use of body cadaver to dissolve fatiii. Indirect Measurement 1. Hydrostatic weighing/Densitometry/Under Water weighing a. Utilizes Archimedes’ principle to measure body density to compare amount of body fat to lean body mass b. % Body Fat = (495/Body Density) – 450 Ex. (495/1.0417)-450 = 25.2% body fat c. Body Density = Db = Ma *Dw/(Ma-Ww-RLV*Dw) Ma = Body Mass (kg) Ww = Net Underwater Weight (kg) Dw=Density of Water, correct for temp RLV = residual Lung Volume Db = Body Density 2. Anthropometric Measurements – using height, weight, girth and skinfolds to estimate body composition a. Skinfold - Measures Subcutaneous Fat i. estimates body fat from interrelationship among: 1. Subcutaneous fat (measured) 2. Internal fat 3. Whole body density ii. Measurement sites: triceps, subscapular, suprailiac, abdominal and upper thigh 1. Problems: different testers measure differently iii. Uses: 1. Comparing individual body fat changes over time 2. Computing % body fat – based of values of similar age, gender, training, race and fatness of individual a. Young women = %Body Fat = 0.55A + 0.31B + 6.13 b. Young Men = %Body Fat = 0.43A + 0.58B + 1.47 A= triceps (mm) B=subscapular (mm) b. Girth – use of tape measure to measure girth of body part i. Assess body fat distribution ii. Measurement sites: right bicep, right forearm, abdomen, buttocks, right thigh, right calf iii. 2.5%-4% erroriv. Waist to Hip Ratio (WHR) 1. Waist/Hip 2. Men <0.95 Men 60+ <1.03 Women < 0.86 Women 60+ < 0.90 c. Body Mass Index (BMI) = Body mass (Kg)/ Sature2 (m2) i. Limitation: doesn’t consider age, gender, ethnicity and race. And doesn’t consider body composition (muscle vs fat) ii. Classification 1. Underweight <18.5 kg*m2 2. Normal 18.5 kg*m2 to 24.9 kg*m2 3. Overweight 25 kg*m2 to 29.9 kg*m2 4. Obese >30 kg*m2 to 3. Bioelectrical Impedance – use of electrical impulse to determine body composition a. Fast electrical conduction: Fat-free Body mass and water, because of higher electrolyte content b. Slow conduction: fat and bone tissue c. Utilizes Ohm’s Law = Resistance = volume/current d. Problems: electrode placement, body position, hydration status, plasma osmolality, sodium concentration, skin temperature, recent physical activity, and previous food intake can all affect readings. 4. Bod POD – measures body volume to asses body fat% a. As reliable as DEXA or Under Water Weighing 5. Dual Energy X-Ray Absorptiometry(DEXA) – scans body to determine body composition, as reliable as Under water weighing 3. National epidemic of overweight and obesity a. Increased number of Overweight and Obese individuals i. 65% of Americans are Overweight, 33% are Obese ii. increasing health problems, shorter life iii. Causes: Increased Caloric intake (overfed) & decreased physical activity, Genetics b. Adipocytes (Fat cells) i. Increases in Size (Hypertrophy) and Number (Hyperplasia) (weight gain) ii. Can only decrease in Size (weight loss) c. Body Fat Norms: i. Men – Avg is 15%, range 10-22% ii. Women – Avg is 26%, range 20-32% 4. Weight loss with the energy valance equation a. Weight Change = Total Energy intake – Total Energy Expenditure i. (-) Weight loss, (+) weight gainii. Reduce Caloric intake (500-1000cal/day) and/or increase exercise, make good food choices iii. Ideal diet/exercise combination: offers more flexibility to achieve negative calorie balance, weight loss and health benefits, and longer maintenance of weightPulmonary Ventilation – supplies Oxygen required in metabolism, eliminates carbon dioxide and regulates hydrogen ion concentration to maintain pH. 5. Understand the mechanics of breathing including the sequence of events. a. Conducting Zone – oxygen is transported (no Alveoli) – Trachea and terminal bronchioles b. Respiratory Zone – gas exchange occurs – Bronchioles, alveolar ducts and alveoli. c. Sequence of Events: i. Muscle Contraction (diaphragm) ii. Change in volume of chest cavity causes change in pressure iii. Movement of Air 1. Inspiration – moving air in, active 2. Expiration – moving air out, passive 6. Be able to differentiate the lung volumes and understand the response to exercise for each lung volume a. Tidal Volume – volume inspired or expired per breath i. Increases with intensity of exercise b. Inspiratory Reserve Volume – Max inspiration at end of tidal inspiration i. Decreases with exercise c. Expiratory Reserve Volume
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