Unit 11 Physical Activity PDF

Physical Activity UNIT 11 NUTR 1100- Introduction to Nutrition What is physical activity? Physical activity Any bodily movement produced by skeletal muscles that results in energy expenditure. In daily life, it can be categorized into occupational, sports, co...

Physical Activity UNIT 11 NUTR 1100- Introduction to Nutrition What is physical activity? Physical activity Any bodily movement produced by skeletal muscles that results in energy expenditure. In daily life, it can be categorized into occupational, sports, conditioning, household, or other activities. Exercise a subset of physical activity that is planned, structured, and repetitive and has as a final or an intermediate objective the improvement or maintenance of physical fitness. Physical fitness set of attributes that are either health- or skill-related to the ability to perform physical activity. Components of fitness Cardiorespiratory endurance Muscle endurance Muscle strength Flexibility Body composition Cardiorespiratory endurance Ability to sustain cardiorespiratory exercise for an extended length of time (walking a mile vs stairs) Improved by aerobic exercise Increases aerobic capacity= max. amount of O2 that can be consumed by the tissues (VO2 max) Muscle strengthening Muscle strength: the amount of force that can be produced by a single contraction of a muscle It enhances the ability to perform tasks such as pushing or lifting Muscle endurance: the ability of a muscle to continue sub-maximal, repetitive movement over time Resistance (strength) training: increases muscle strength, endurance and size Includes weight-lifting and calisthenics Flexibility Range of motion around a joint and improved by stretching Reduces likelihood of injury Body composition Proportion of muscle, water, fat and other tissues Together – total body weight Body comp can change without change in weight (muscle takes up less space per pound than fat) You can lose inches without tipping the scale Health benefits to exercise Physical activity recommendations Most Canadians do not exercise regularly Only 15% Canadians get the recommended amount of physical activity To address the problem, the Canadian Society for Exercise Physiology (CSEP/SCPE) issued two sets of guidelines 1. Canadian Physical Activity Guidelines 2. Canadian Sedentary Behaviour Guidelines Canadian Physical Activity Guidelines 24 hr Movement Guidelines http://csepguidelines.ca Complete fitness program The complete fitness program should include: – Aerobic exercise for cardiovascular conditioning – Resistance exercise or strength – Stretching exercises for flexibility Aerobic exercise Aerobic activity: low to medium intensity continuous exercise. raises heart rate to 60–85% of maximum heart rate Maximum heart rate = the maximum number of heart beats per minute Energy production: 3 systems Aerobic metabolism: with oxygen Uses carbohydrates, fat and occasionally protein More efficient; produces more ATP, almost unlimited capacity to continue production Low to medium intensity with steady state/continuous activity Anaerobic metabolism: without oxygen Only uses glucose Fast but runs out within a few minutes Higher intensity and shorter bursts ”Quick” or Phosphagen Energy System: Uses stored energy precursor in the muscles (Creatine Phosphate) Fast but runs out within 20-30 seconds Highest intensity and very short duration Aerobic vs. anaerobic metabolism Aerobic metabolism Anaerobic metabolism Use of Yes No oxygen Nutrients glucose used to fatty acids Only uses glucose generate amino acids ATP Produces 18X more ATP ATP for each glucose Produces lactic acid Production molecule (more efficient) Energy Production: compare System Fuel Type of effort Examples of activities Aerobic Carbs Low to med intensity Endurance Energy Fats Continuous/steady state running System activity (longer duration) Hiking Triathalons Anaerobic Carbs Medium to higher intensity Judo, jiu jitsu and Energy Short bursts of a few other martial arts System minutes max High intensity interval training Strength training “Quick” or Creatine High intensity 100 m sprints Phosphagen Phosphate very short duration Power lifting energy (made from Some parts of system proteins) basketball Exercise duration and fuel use First few seconds of exercise: Stored ATP is used then creatine phosphate is broken down to make ATP After about 15 seconds of exercise: Anaerobic metabolism uses glucose to make ATP After 2–3 minutes of exercise: Breathing and heart rate increase Aerobic metabolism uses glucose to make ATP Longer duration: aerobic metabolism of fatty acids and glucose (protein when not enough glucose) Exercise intensity and fuel use  Fatigue Inability to continue activity at optimal level Occurs when glycogen stores are depleted or athlete is dehydrated (we need water for energy production) Occurs much more quickly with high-intensity exercise because it relies more on anaerobic metabolism, which only uses glucose More likely to occur when an athlete has not properly filled glycogen stores Fatigue: Glycogen depletion  Limited amount of stored glycogen available to produce glucose during exercise  Glycogen depletion: overwhelming fatigue, sometimes referred to as “hitting the wall,” or “bonking” Diet needs for physical activity Energy needs to fuel activity depend on energy expenditure which is associated with: the intensity, duration, and frequency of the activity and the weight of the exerciser Protein to maintain muscle mass Micronutrients to support use of energy-yielding nutrients Water to transport nutrients and cool the body  Water needs for physically active individuals Exercise increases water needs because it increases water losses in sweat and respiratory system evaporation Risk of dehydration is greater in hot than cold environments but can occur in the cold During exercise, needed to cool the body, transport oxygen and nutrients to the muscles, and remove waste products Vitamin and mineral supplements Supplements found not to improve performance, muscle mass or strength: Vitamin B6, B12 and folic acid promoted for aerobic exercise Vitamin E, vitamin C and selenium promoted for their antioxidant functions Chromium picolinate and vanadium promoted for increase in lean body mass (both) and loss of fat (chromium picolinate)