Final Review for EXSC 408
Final Review for EXSC 408 EXSC 408
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This 13 page Study Guide was uploaded by Ticynn London on Wednesday April 27, 2016. The Study Guide belongs to EXSC 408 at Old Dominion University taught by Kim Baskette in Spring 2016. Since its upload, it has received 41 views. For similar materials see Nutrition in Physical Education at Old Dominion University.
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Date Created: 04/27/16
Final Exam Review Classification of Vitamins Micronutrients needed for proper physiological functioning - Typically classified based on solubility Physiological function ¡ Energy ¡ RBC formation ¡ Antioxidants- kills free radicals ¡ Growth and development DRI & UL ¡ UI only established for 8 of 14 due to lack of scientific data Absorption & transportation Fat-soluble vitamins ¡ Absorbed & transported in same manner as fats ¡ Occurs with in several hours ¡ Stored in liver and adipose tissue Water-soluble vitamins ¡ Readily absorbed & circulate in blood unbound ¡ No designated storage site in the body ¡ Once saturation in tissues occurs, excess amounts excreted in urine (B6- nervous system damage) ¡ Consumption of excess amounts can result in toxicity with some vitamins Exercise & vitamins Potential effects of moderate to vigorous exercise ¡ Decrease absorption from GI tract ¡ Increase excretion in sweat and urine ¡ Increase utilization ¡ Increase need to due to growth and maintained of SM mass Are DRI levels sufficient for moderate to vigorous training? ¡ Studies focused mainly on B vitamins & antioxidants (E, C, & A) ¡ Some evidence showing increase need for B6, riboflavin and thiamin during exercise. Diet and Vitamin Level Low intake found amongst athletes & sedentary adults Inadequate energy intake Adequate energy intake with poor food choices Vitamin deficiencies Occurs through progression of stages ¡ Subclinical & clinical deficiencies Mild deficiencies ¡ Develops over time due to low or absent vitamin intake ¡ Causes – nutrient intake, GI disease (lack of B12) Moderate deficiencies ¡ No clinical signs of medical disease ¡ Physiological functions begin to be affected with subtle changes ÷ Vit A –vision change ÷ Vit D – Bone pain and muscle weakness Clinical deficiencies ¡ Development of disease associated with vitamin deficiency ÷ Manifestation of medical signs & symptoms ÷ Examples Beriberi – thiamine Rickets - Vit D Pellagra- Niacin ÷ Developing toxicities ¡ Normally takes months to years to develop ¡ Initial symptoms –lethargy, clinical manifestation ¡ Rare in U.S. – reported with A, D, and B6 ¡ Multivitamin supplements Roles of vitamins in the body Contain unique chemical composition & biochemical roles ¡ Cofactors for enzymatic reactions (coenzyme)- all B vit Complex processes in the body ¡ Vit E and C, and beta-carotene anti-oxidative properties Differentiation, growth, development, & cell maintenance ¡ Examples: Vitamin A – proper cell differentiation Vitamin D – bone formation Interact with other vitamins & minerals ¡ Ex. Vitamin C – interacts with Fe and Cu to allow for optimal absorption Mineral Classification of minerals Twenty-one essential minerals ¡ Macrominerals – large amounts ¡ Microminerals – small amounts Functions - Bone formation - Electrolytes (Na, K, Cl) - RBC formation - Coenzymes - Immune system function Mineral Loss Sweat – biggest, concern with loss of Na, Cl, and K ¡ Adaptation to heat: in conservation of Ca, Mg, Fe, Cu, and Zn Urine ¡ Acute exercise ÷ Increased Zn: blood levels increase excretion ÷ Increased Fe: excretion compared to sedentary indv. Moderate losses may be offset by adequate food intake Adequate mineral intake from foods Athletes with low energy intake likely to be deficient in one or more: Ca, Fe, Zn, Se, Mg, Cu Higher incidence in distance runners, gymnasts, ballet dancers, teenage synchronized skaters, wrestlers, & jockeys - Subs with Fe and Zn (fortified foods) Mineral balance Mineral balance - interplay of storage, absorption, & excretion: stored in tissues (will alter) Hormonal control – maintains levels of some minerals (Ca) Absorption of minerals ¡ Dependent on levels in body ¡ 70% of P consumed in diet normally (rates can drop) Mineral Absorption Competition for absorption occurs based on amounts consumed ¡ Occurs primarily with divalent cautions - Same binding agents and cellular receptor site - Ca, Fe, Zn, Cu, Mg ¡ Problems can be created with excessive intake of one mineral through supplements: absorption of Cu, Fe, and Ca decreases with Zn Better absorbed when food present in GI tract Compounds known to interfere with absorption Phytic acid (phylates)& oxalates Sugars: Cu, Mg, Zn Soluble Fibers: pectin, gum Ascorbic Acid: Fe Insoluble fiber Compounds known to increase absorption Vitamin C in oranges increases absorption of Fe found in plant foods, such as the beans used in chili. Mineral deficiencies Can occur over time with low intake levels ¡ Progression from subclinical to clinical deficiency ¡ Ex. Zn deficiency ÷ Subclinical – decrease appetite, poor healing ÷ Clinical deficiency – impaired taste, night blindness Subclinical deficiencies ¡ Fe deficiency without anemia ÷ Incidence rate estimates in female adolescent & adult athletes ÷ Fe (25-36% female) ¡ Osteopenia ÷ Incidence rate estimates – Men - 30% ÷ Women - 49% ÷ Athletes – 11-22% Fe deficiency anemia – fatigue, reduction in aerobic capacity & endurance: 3% of women 12-49yrs Osteoporosis ¡ Prevalence – 8 mil women and 2 mil men older than 50 ¡ Female athletes – can occur with prolonged low caloric intake concurrent with high-energy expenditure ÷ Reduces amount of circulating estrogen ÷ Amenorrhea – result of low energy Water and Fluid Balance Comprises approximately 60% of body weight Range_ 40-80% Functions - Aqueous medium for chemical reactions/cell process - Transport of substances through the body - Thermoregulation Fluid balance - Water volume - Solute concentration Osmosis - Movement of water through a semipermeable membrane to areas of high solute concentration Tonicity - Hypotonic- water moves in - Isotonic - Hypertonic- more soluble outside, water moves out; cells shrivel and die - Primarily affected by electrolyte concentration Water concentration in body - Average male - 60% (approx. 42L for 70kg) - Average female – 50-55% (30L) Water distribution in body - Blood plasma - Muscles & other organ tissues - Bone - Adipose tissue Distribution of body water Intracellular fluid compartment - Approx. 2/3 of body water Extracellular fluid compartment - Approx. 1/3 of body water (14L or ~3.5 gallons) - Plasma - 20% of total ECF volume (3L or 3Qrts) - Transport; thermoregulation Interstitial fluid – 80% of total ECF (11L or 3gallons) - Protection Lymphatic system Tonicity Hypertonicity - Heavy sweating - Large loss of plasma volume - Increased concentration of plasma Na+ - Water movement Hypotonicity - Consumption of large amounts of water very quickly - Nerve cells can cease to function properly - Ex. 3,000ml or ~13C in 4hrs + - Dilutes ECF resulting in decreased plasma Na Water movement Water loss Insensible – H20 loss through channels not normally noticed Sensible Primary channels – urine, sweat, feces Influences on water loss - Fluid & salt intake - Renal function- major role in fluid balance control Action of various hormones Consumption of diuretic compounds Fluid Balance Diuretics - Alcohol – inhibits production of ADH - Prescription medications- may block reabsorption of fluid &/or electrolytes - Caffeine & theophylline – increases urine output - Herbs Sweating- thermoregulatory mechanism Water intake Average daily intake - ~ 2,350ml from beverages & foods Food – 20-25% Tap and/or bottled water – 35-40% Other sources – 35-45% Aerobic metabolism – 350ml (12.5oz) of daily water Regulated by water volume & osmolality of ECF Hypernatremia & endurance athletes Clinical hypernatremia – plasma level <135mmol/L Exercise-induced hypernatremia – rapid drop less than 130 Involves endurance events lasting >7hrs with significant sweat loss Ultraendurance running events – 10% Ironman Triathletes – 29% Swelling of nerve cells can cause dizziness, confusion, seizure, coma, & death 0.5-0.7g/l fluid Strategies for prevention Replacement of Na & prevention of fluid overload Events lasting >2-3hrs should include Na replacement Sodium intake Daily intake Consumed primarily as NaCl: 1/4tsp of table salt (1000mg of NaCl has 40% Na) = 1.5g NaCl Processed food – 77% Table salt – 11% Naturally in foods – 12% Average daily Na intake Males – 4200mg Women – 3300mg Exercise and fluid balance Under normal conditions, fluid balance easily regulated Exercise: increase body temp and fluid loss via sweating Decrease in plasma volume Leakage of fluid from plasma into the interstitial spaces Dependent on intensity of exercise Intense exercise – small losses (5%) w/o sweating Prolonged exercise – large losses (10-20) w/ sweating Exercise and fluid balance Factors affecting increase in sweating Exercise intensity Environmental conditions Clothing Training status- higher sweat rates; more effective thermoregulatory Variations in sweat loss Non-exercise, normal temperature environment - 100ml Exercising in elevated temperatures – 300-1200ml/h Exercising in elevated temps with protective clothing – 1-2l/h Athletes competing in team sports & prolonged endurance events in hot environments – 2.5l/h Athletes competing in aquatic events Have been shown to have elevated sweat rates Cold climates – water loss from ventilation Hypohydration Hypovolemia: Loss of blood volume: increase osmolality of plasma Increase in body core temperature: every 1% loss of body weight as water, about 0.1-23 c increase core temp Impairment in ability to dissipate heat resulting in higher body temperatures Decreased thermoregulatory control in brain May result in hyperthermia leading to heat stroke, coma & possibly death Electrolyte loss during exercise + - Greatest loss - Na and Cl Exercising <2hrs: electrolyte loss not likely; fluid replacement should be focused on water intake Exercising >2hrs: electrolyte replacement with sodium Replenishment of water & electrolytes Determining hydration status Amount of total body water Plasma osmolality Provides accurate assessment at single point in time Analysis of urine output Higher specific gravity, osmolality, & darker color seen in hypohydration Urine testing strips available Changes in body weight Weight loss from single exercise session likely due to fluid loss Can be used as a benchmark for subsequent rehydration Ex. Athlete engages in intense exercise lasting one hour & loses 2kg 1L water weighs 1kg which translates to loss of 2L of water If only 1kg gained back the following day, signifies inadequate fluid replenishment Hydration assessment tool Pre-exercise hydration Pre-exercise beverage Water normally sufficient with slow fluid intake beginning at least 4hrs prior, if possible: 5-7ml/kg should be sufficient Sodium – stimulates thirst and retention of body weight Carbohydrates - Recommended additional intake of 3-5ml/kg-2hrs priors Hypohydration state prior to exercise Inadequate restoration of fluid from previous day’s exercise Multiple exercise bouts in hot and/or humid conditions Voluntary restriction of fluid to reduce body weight Amount & timing should be individualized Too little fluid intake: dehydration Too much fluid intake bloating Hydration strategy guided by: Intensity & duration of activity Potential effect of hypohydration on performance Environmental conditions Intake during training & performance Goals Replace body fluid Delay dehydration Replace sodium Avoid overconsumption and GI distress ACSM recommendations Marathon runners – 0.4-0.8l/h Drink or schedule w/ goal not to lose more than 2% of body weight Current Guidelines Develop a customized plan that considers sweat rate, sweat composition, duration, clothing, & environmental conditions Replenishment after training & performance Goals: Replace water loss, sodium and other electrolytes Plasma Na increases during exercise due to loss of water Consumption of adequate carb and protein Avoid GI distress Recommendations 1.5L/kg of body weight lost Na containing beverages: exercise for >4hr and heavy sweating Iv replacement: no evidence Supplement use among athletes 85% or more of all elite athletes reported using one or more dietary supplements Multivitamins, vitamin C, creatine, protein powders & protein drinks Approximately 70% of adolescent athletes reported to consume at least one supplement Capitalizes on fears and hopes Misinformation; lack of education Direct advertising Nutritional quackery Fake practitioners; worthless products with deceitful promotion of products Approx. $34 billion annually on questionable health practices Disclaimers on labels “These statements have not been evaluated by FDA” “This product not intended to diagnose, treat, cure, or prevent any disease” Supplements & mineral intake Advertised as “a way to obtain various minerals that may be missing from an athlete’s usual diet” Ca & Fe most frequently taken as individual supplements- should be taken at different times to reduce competition for absorption Fe supplementation Appropriate treatment for diagnosed Fe deficiency anemia Ferrous sulfate (325mg; 65mg Fe) 3-6 months Restoration of iron stores 3-6 months Ca supplements Absorption rate similar to milk (400-500mg optimal dosage) Single supplementation of other minerals May be disruptive to absorption of other nutrients especially in high dosages Some advertised as “high bioavailability” Chromium Trace mineral: taken by athletes to increase muscle mass and decrease body fat Sold as chromium picolinate Picolinate stabilizes compound & increases GI absorption Often sold as herbal supplement Can enhance insulin sensitivity & improve glucose utilization Recommended dosage: 1 tablet Carnitine Derived from AA & found in nearly all cells in body Highest amounts in cardiac muscles Enhances transports of long-chain fatty acids into the mitochondria Adequate amounts from food May synthesize form lysine Often promoted to aid in weight loss, improve exercise performance, and enhance sense of well-being No consistent evidence supporting use to increase muscle mass, alter fat metabolism, or improve performance Can be prescribed to treat carnitine-deficiency syndromes Omega 3’s Claims: reduces inflammation, effects of oxidative stress, & counteracts immune dysfunction associated with strenuous exercise Studies inconsistent on benefit on heart disease Some evidence suggesting use is modestly helpful in relieving symptoms in RA patients FDA recommendation - ≤3g/d EPA & DHA from all sources & ≤2g/d from dietary supplements Caffeine CNS stimulant- heightened sense of awareness and reduce perceptions of afford Increases rate of lipolysis during exercise Enhances mobilization of fatty acids Increases perception and ability to work harder Found to decrease hunger during recovery Enhancement of performance with moderate dosages Maximum effective dosage – 3-4mg/kg Positive effects seen with 2mg/kg; use as starting point in establishing optimal dosage Amino Acid Beta-alanine for high-intensity exercise Dispensable AA found in foods as part of carnosine (act as a buffer) Found to improve high-intensity exercise performance by 2.85% (most effective for exercise lasting 90-240 sec) Dosage – 2-6 g/day has been shown to increase carnosine concentrations in skeletal muscle by 20-80%. Side effects - tingling & burning of skin (time release) Branched Amino Acids Leucine, isoleucine, valine- metabolized for energy Used to reduce skeletal muscle damage & delay muscular fatigue in trained athletes- no evidence Preliminary studies in untrained subjects- reduce soreness for squats Leucine – found to increase rate of protein synthesis 2-3g/d (young adults); 3-4g/d (older adults) Glutamine Dispensable AA under normal conditions- fuel source for immune system Decrease in production below what’s needed by the body may occur during prolonged endurance exercise - Exercise induce impairment Research: Not effective in counteracting immunologic stress & reducing immune system suppression- no evidence Glucosamine/chondroitin sulfate Glucosamine manufactured in body from glucose & glutamine as part of glycosaminoglycan - Joint lubricant Chondroitin – part of protein that aids in elasticity of cartilage Marketed to relieve joint pain in osteoarthritis & prevent cartilage breakdown in athletes Recommended dose – 1,500-1200mg/d Beta-hydroxy-beta-methylbutyrate (hmb) Metabolite of leucine- transport from liver to muscles Prevents protein degradation Evidence has shown increases in muscle mass and strength in resistance training Effect seen in reducing muscle damage in untrained individuals Optimal dosage: 3g/d- Works well with carbs and proteins Nitric Oxide Produced directly from L-arginine consumed in diet (ex. nuts, fruit, meats, & dairy) Released from lining of arteries during activity Supplementation Dosage: Shown to improve exercise performance @ all intensities
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