PA_safety - Why participate in physical activity? 1. Lowers...

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Unformatted text preview: Why participate in physical activity? 1. Lowers risk of most major diseases 2. Supports mental & emotional well-being 3. Supports immune function 4. Promotes physical health & well-being Components of Fitness 1. Flexibility Especially important with agingallows for performance of activities of daily living (ADLs) & prevention of falls Components of Fitness 1. Strength achieved with weight training Building back & abdominal muscles helps with posture Helps prevent decline of physical mobility Leg strength & walking endurance are strong indicators of an older persons physical ability Components of Fitness 1. Endurance Need oxygen provided by heart & lungs Total blood volume & number of red blood cells increases Builds respiratory & heart muscles & improves efficiency (> stroke volume) Components of Fitness 1. Cardiorespiratory health allows for efficient delivery of oxygen Need sustained activity of 20 minutes or more to achieve beneficial effects Contraction of skeletal muscles helps propell blood against gravity Fuels for Activity Depends on intensity, duration & prior training Rest : slightly more than half of energy comes from fatty acids the rest comes from CHO & a small amount from protein Activity : initial energy sources come from stored glycogen in muscles as activity continues, the liver & fat cells release glycogen & fatty acids Glycogen (Carbohydrate) Glycogen is the storage form of glucose Found in the muscle & liver As levels of glucose in the blood decline, the liver releases glycogen Stores are continually being repleted With vigorous activity, can be depleted in a few hours Intensity Moderate (aerobic) adequate 0 2 is available to muscles so the body can use both glucose & fatty acids for energy Strenuous (anaerobic) fatty acids cant be used due to 0 2 deficiency so muscles depend heavily on glycogen stores Results in the production of lactic acid Accumulation of lactic acid, results in hormone release that increases heart & respiratory rate to try to breakdown lactic acid Lactic acid build up results in burning muscles followed by fatigue Once the activity slows, the lactic acid is metabolized & used for energy or the production of glucose Duration 1 st 10 min, muscle relies on glycogen As moderate activity continues, muscles pull glucose from the blood & blood sugar drops After 20 min, the muscles begin to use < glucose & rely more on fat for fuel As glycogen stores become depleted, the liver produces some glucose from lactic acid & certain amino acids When hypoglycemia accompanies glycogen depletion, CNS function becomes minimal making activity hard (hitting the wall) Training strategies for postponing exhaustion due to depletion of glucose 1. Eat a high carbohydrate diet 2. Take in glucose during activity Beneficial if activity last for hours & requires bursts of intense energy (soccer, hockey) Not likely beneficial in activities that last < 1 hour Training strategies for postponing...
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This note was uploaded on 07/05/2010 for the course NH 311 taught by Professor Dawson during the Spring '10 term at Oakland University.

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PA_safety - Why participate in physical activity? 1. Lowers...

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