HNSC 1210_Chapter 10 Student.pptx

Chapter 10 PHYSICAL ACTIVITY Benefits of Physical Activity More restful sleep ↓ Risk CVD ↑ Nutritional health ↓ Type 2 diabetes ↑ Body composition ↓ Gallbladder disease ↑ Bone density ↓ Anxiety/depression ↑ Immunity ↑ Self-image...

Chapter 10 PHYSICAL ACTIVITY Benefits of Physical Activity More restful sleep ↓ Risk CVD ↑ Nutritional health ↓ Type 2 diabetes ↑ Body composition ↓ Gallbladder disease ↑ Bone density ↓ Anxiety/depression ↑ Immunity ↑ Self-image ↓ Cancer risk Longer lifespan ↑ Circulation/lung function ↑ Quality of life Canada’s Guide to PA New guidelines released in Jan 2011 Guidelines for adults 18-64 years: ◦ At least 150 minutes of moderate to vigorous intensity activity per week ◦ Add up activities in periods of at least 10 minutes ◦ 2 days per week: muscle and bone strengthening activities More physical activity (to a degree) = greater health benefits Meeting guidelines can help reduce risk of many chronic diseases Fuel Use (1) Fuel use depends on intensity and duration At rest: ◦ ½ fatty acids, other ½ mostly glucose, some AAs During activity: ◦ Early minutes: majority from muscle glycogen ◦ As activity continues: glucose and FAs Fuel Use (2) Fig 10-4 Anaerobic activity: (no oxygen) ◦ Maximal exercise of short duration (intense activity, e.g., ¼ mile race) ◦ Energy (ATP) from glucose (glycogen) Fuel Use (3) Anaerobic activity (continued) ◦ Produces lactic acid ◦ Muscles can use some lactic acid, but when production exceeds use → sent to liver ◦ Liver enzymes convert back to glucose → sent to muscles to fuel additional activity ◦ Can accumulate, but does not cause muscle fatigue Fuel Use (4) Aerobic activity: ◦ Moderate activity (e.g., jogging) ◦ Requires oxygen, produces carbon dioxide ◦ Energy (ATP) from glucose (glycogen) and fat ◦ Highly trained muscles use less glucose and more fat than untrained muscles, thus, glycogen lasts longer Effect of Diet on Physical Endurance: Carbohydrates Diet strategies to maintain CHO concentrations ◦ Eat high CHO diet daily ◦ Fig 10-5, Fig 10-6, Table 10-5 ◦ High CHO diet enhances athlete’s endurance (ample glycogen stores) Fig 10-3 Carbohydrates Diet strategies to maintain CHO concentrations ◦ Take in some glucose during activity ◦ Eat CHO-rich foods within ~2 hours post activity (boosts muscle glycogen stores) ◦ CHO loading CHO Loading Table 10-1 ◦ Regimen of moderate activity, followed by eating high CHO diet ◦ Allows muscles to store more glycogen (to nearly double normal muscle storage levels) ◦ Benefits athletes in long duration activities (>90 minutes) Fats High fat diets impair performance Too low (20 mins duration shift to burn more fat, less glycogen for energy Protein Eating protein with CHO within 2 hours post activity: ◦ Can enhance muscle protein synthesis ◦ CHO rich diet spares protein from being used as fuel Protein needs ◦ Higher for both endurance and strength athletes (Table 10-2) Protein & Muscle Growth 1 lb muscle = 70 – 105g protein ◦ To add 1 lb of pure muscle per week, need to add 10-14g protein per day ◦ 3 oz chicken = ~30g protein ◦ 2 slices pork tenderloin = ~25g protein ◦ 1 lean ground beef patty = ~20g protein Can build a maximum of 2 lbs muscle/week Excess protein taken in is converted to glycogen or fat Vitamins & Minerals Supplements: ◦ Do not enhance performance if well nourished ◦ Can help if athlete is deficient (deficiencies can impede performance) Vitamin E: ◦ May protect against exercise induced, oxidative stress; no improvement in performance Iron: ◦ Female athletes at special risk for iron deficiency ◦Anemia can impair performance (O 2 handler) Fluids & PA (2) Hot humid environment ◦ Fluid loss > 2 litres/hour ◦ Increased risk of dehydration and heat stroke (elevated body temp) ◦ Drinking cool water before, during and after physical activity (can absorb ~1 L/hr) Cold environment ◦ Room temp/warm water to reduce risk of hypothermia Electrolytes are replaced by eating a balanced diet afterwards Sports Drinks (1) Water, glucose, minerals, electrolytes Benefits from glucose if activity >45-60 min ◦ Helps maintain blood glucose ◦ ~7% sugar; if sugar too high, it delays stomach emptying and Photo Source intestinal absorption of water ◦ Sugar may add unwanted calories Sports Drinks (2) Homemade recipe ◦ 1 cup fruit juice ◦ 2-3 cups water ◦ 1/3 teaspoon salt (optional) Fruit juice and regular soft drinks are too concentrated in sugar, etc. Caffeine and alcohol are diuretics ◦ Beer facts (p. 450): 2/3 calories from alcohol; mineral-poor, vitamin- poor Complete Meal Replacers Marketed as “complete” meals, but often fall short Calories often from fat and sugars Good for athletes with “pre-game jitters” unable to tolerate solid food on day of event Should not be used as sole source of nutrients – hard to meet high nutrient needs Homemade replacers just as good and cheaper (Table 10-6) Chapter 10 PERFORMANCE ENHANCING/ERGOGENIC AIDS Learning Objective You will be able to weigh the benefits and dangers of some performance enhancers/ergogenic aids commonly used by athletes Ergogenic Aids Ergogenic aids: products that supposedly enhance performance ◦Implies “energy giving” Many are regulated under Natural and Non-prescription Health Products in Canada Some are banned in Canada Some are condemned by the Canadian Center for Ethics and Sports, and are banned by International Olympic Committee Most have not been proven to be effective in improving performance, and are unnecessary Many have serious side effects Amino Acid Supplements Consumed for building larger muscles Extra AAs do not lead to muscle building ◦ They are stored as energy after the removal of nitrogen, increasing nitrogen excretion AAs compete for absorption ◦ Such supplements can limit the availability of other AAs A well-balanced diet provides sufficient essential AAs to build muscles Caffeine Endurance athletes may get the benefit of energy boost but provides no advantages during high-intensity activity ◦ Mechanism of action is not understood, might just be “wake-up” effect Side-effects: dehydration, stomach upset, irritability, constriction of arteries causing increased blood pressure causing increased work for the heart ◦ Could be detrimental to sports performance Common sources/products: coffee, energy drinks, guarana, some carbonated drinks Anyone exceeding the urinary limit of 12 mg/ml faces a ban leading to disqualification by International Committee of Olympics (5 to 6 cups of coffee within 30 minutes period) Carnitine Non-essential nutrient needed by our cells to transport fat molecules across the mitochondrial membrane ◦ This logic is used to advertise the claim that carnitine increases fat burning ◦ No evidence that carnitine increases fat burning and energy production Oral carnitine is not prohibited in international sports Body can produce all the carnitine it needs as it is a non-essential nutrient Creatine Some scientific evidence exists that creatine enhances performance during intense activity ◦ Many studies show no such effect Creatine metabolism leads to production of the toxin formaldehyde ◦ Long-term safety is unknown May cause kidney damage Not illegal in international competitions Hormone Preparations Anabolic steroid hormones (including steroid alternative supplements) Naturally produced by male testes and adrenal glands, and female adrenal glands Synthetic forms accelerate muscle growth Banned by International Olympics Committee and condemned by The Canadian Centre for Ethics and Sports (CCES) because they give an unfair advantage to the athletes using such products Side effects: liver tumors, heart disease, dramatic increase in aggressive behavior, severe depression Human Growth Hormone (HGH) Naturally produced during rest, especially after physical activity Synthetic forms lead to abnormal enlargement of organs and bones Banned by International Olympics Committee and The Canadian Centre for Ethics and Sports (CCES) because they give an unfair advantage to the athletes using such products Side effects: diabetes, heart diseases, thyroid disorders, menstrual irregularities, and increased likelihood of death before the age of 50 Critical Thinking What forces do you think might motivate a competitor to ignore the side-effects and use such ergogenic aids?