Chapter 9 Physical health

• Physical activity


  Bodily movement that is produced by the contraction of skeletal muscles that increases energy expenditure above a basal level
• Exercise


  Subcategory of physical activity, planned, structured, and repetitive bodily movements done to improve or maintain physical fitness
• Physical fitness


  The ability to carry out daily tasks with vigor and alertness, and to perform leisure-time pursuits without undue fatigue
• Reasons to exercise


  • To stay in shape
  • Improve overall physical health
• Health benefits of physical activity

  • Weight management
  • Reduced risk of high blood pressure
  • Decreased risk of cardiovascular disease
  • Reduced risk of cancer
  • Decreased back pain
  • Lower risk of type 2 diabetes
  • Optimized bone health
  • Enhanced self-esteem, stress management, and quality of sleep
• Components of physical health

  • Cardiovascular fitness
  • Muscle strength
  • Muscular endurance
  • Muscular flexibility
  • Body composition
• Cardiovascular fitness


  • Uses larger muscles, enhances circulatory and respiratory systems, improves oxygen delivery, improves heart rate, blood pressure may drop, breathing is more efficient
• Muscle strength


  • How hard your muscle can work (e.g., how much weight can you lift), the maximal force exerted by muscles during an activity, challenge specific groups of muscles to make them work harder, keep muscles and bones strong
• Muscular endurance


  • How long your muscle can work before you become fatigue (more repetition), the ability to exercise for an extended period of time without being fatigued
• Muscular flexibility


  • The range of motion around a joint
• Body composition


  • Cardiovascular exercise helps to decrease body fat, whereas muscle mass can be increased through strength-building activities (e.g., lifting weights)
• Physical activity recommendations for adults

  • At least 2.5 hours (150 mins) a week of moderate-intensity physical activity
  • 1.25 hours a week of vigorous-intensity aerobic physical activity
  • 2 or more days each week of resistance training of moderate-intensity activity
• ACSM recommendations for adults (healthy)

  • Cardiorespiratory exercise
  • Resistance exercise
  • Flexibility exercise
  • Neuromotor exercise (functional fitness training)
• Cardiorespiratory exercise


  • Exercise that involves major muscle groups, brisk walking, jogging, running, dancing, stair climbing, cycling, rowing, cross-country skiing, and swimming, at least 150 mins of moderate-intensity exercise/week, 30-60 mins of moderate-intensity exercise, lowering blood pressure, improving blood lipid profiles, enhancing blood glucose regulation, and promoting a favorable ratio of lean-to-adipose tissue
• Resistance exercise


  • Free-weights, machines with stacked weights, and resistance bands, increase muscle strength and muscle mass, slows the progression of age-related muscle loss, improves bone mineral density and bone strength, help the ability of muscle fibers to shorten and lengthen when needed improve, teach each major group 2-3 days each week using variety of exercises and equipment, be performed a minimum of two nonconsecutive days each week with a prescribed number of sets and repetitions
• Flexibility exercise


  • Stretching, yoga, ballet, Tai chi, and elastic bands, most effective when the muscle is warm, involves range of motion movement, each stretch should be held for 10-30 seconds, muscle and joint flexibility tend to decrease with age, tight muscles can cause back pain, impair balance, and limit range of motion, stretch for at least 2 days each week
• Neuromotor exercise (functional fitness training)


  • Improves balance, coordination, gait, agility, Tai chi, yoga, advantages for older adults who are at increased risk of falls and related injuries, improve agility and balance in older adults helps decrease the risk of falling 2-3 days per week
• Nutrition supplements


  Consumption of sports drinks, energy bars, or energy gels during vigorous exercise that last for more than an hour exercise can help provide an additional source of glucose and fluids
• Performance-enhancing aids (ergogenic acids)

  Ergogenic acids include vitamins, minerals, herbal products, botanical agents, and extracts from organs or glands
• Performance-enhancing aids


  • Caffeine
  • Creatine
  • Branched-chain amino acids (leucine, isoleucine, and valine)
• Physiological adaptations in response to athletic training

  • Adaptation response enables the body to adjust to the rigors of exercise more effectively and forcefully, magnitude of these changes depends on a person's level of fitness and the intensity and duration of training, training-induce adaptions cause muscle fibers to become larger and stronger "muscle hypertrophy", when a person stops training these muscle gains quickly diminish, muscles that previously experienced hypertrophy but are subsequently not physically challenged can undergo atrophy
• Strength training (weightlifting)


  • Promotes muscle growth by challenging muscles with exercise that is difficult but brief in duration, increases muscle size and strength (hypertrophy)
• Endurance training (Running and swimming)


  • Involves steady, low to moderate intensity activities that are more sustained in duration, beneficial to pulmonary and cardiovascular function, helps improve aerobic capacity (max amount of oxygen the body can use during a specific period)
• Interval training


  • Alternating short, fast bursts of high intensity exercise with slower, less demanding activity, helps improve both aerobic and anaerobic capacities, anaerobic capacity: maximum-intensity short term physical exertion that reflects the energy generating capacity of anaerobic glycolysis
• Training helps muscles to use glucose more sparingly


  • Only small amounts of glycogen are stored in the liver and skeletal muscles, increase capacity to use fatty acids as an energy source helps spare glucose--> delays the onset of muscle fatigue, training increases the ability of muscles to metabolize fatty acids for energy, the ability to "conserve glucose" is important for endurance athletes (runners, cyclists, swimmers)
• Training improves cardiovascular fitness

  • Increased intensity and duration of workouts require muscles to utilize more oxygen for ATP production via aerobic pathways, the cardiovascular system must work harder to increase oxygen delivery to muscle cells, during a hard physical workout heart rate increase (beats/minute), ventilation rate increases (breaths/minute) and stroke volume increase (amount of blood pumped per heartbeat) occurs to deliver adequate oxygen and nutrients to active muscles, physical training improves cardiac function and blood circulation to muscle tissues, making oxygen delivery more efficient, increased blood flow facilitates the removal of metabolic waste products (lactic acids), training increases maximal oxygen consumption (VO2 max)
• Short duration, high intensity activities

  • Cells contain only small amounts of ATP, just enough to keep the muscles working maximally for 2 to 4 seconds, ATP --> ADP + P1, to maintain ATP level and sustain muscle contraction, the phosphagen system comes into play, when ADP begins to accumulate in a contracting muscle, enzyme "creatine kinase" facilitates the transfer of phosphate group from phosphocreatine (PCr) to ADP, regenerating ATP, phosphocreatine (PCr): high-energy compound stored in muscles, and can quickly donate a phosphate group to ADP to form ATP
• Short-term energy anaerobic pathways

  • Once the phosphagen stores are depleted, within the first 10-15 seconds of high-intensity exercise, you are no longer able to rely on the phosphagen system to supply ATP, the next primary source of energy becomes glycogen stored in the muscles and liver, glycogenolysis: glycogen --> glucose, glycolysis: glucose --> ATP (provides energy for moderate to high-intensity exercise lasting up to several minutes), during intense exercises, oxygen availability is limited (anaerobic conditions), glucose becomes a primary source of ATP production (faster, provides rapid energy to support short bursts of intense activity), glycolysis: glucose --> pyruvate, this reaction does not require oxygen (anaerobic), but yields small amount of ATP, if oxygen is absent (anaerobic pathway), pyruvate converts to lactate, if oxygen is present (aerobic pathway), pyruvate gets metabolized and yields more ATP
• Physical activity at component of energy expenditure
• Energy expenditure rate during physical activity

  15-36 kcal/min
• Glucose --> ATP


  Provides energy for moderate to high-intensity exercise lasting up to several minutes
• The continuation of high-intensity exercises activities increases the demand for ATP
• During intense exercises, oxygen availability is limited (anaerobic conditions)
• Glucose


  Becomes a primary source of ATP production (faster, provides rapid energy to support short bursts of intense activity)
• Glycolysis produces lactic acid as a byproduct, which contributes to the development of muscle fatigue (burning sensation during high-intensity exercise)
• Glucose becomes the major fuel for short-term, high-intensity exercise
• Glycolysis


  Glucose --> pyruvate
• This reaction does not require oxygen (anaerobic), but yields small amount of ATP
• 1 Molecule of glucose breaks down to 2 pyruvate and yields 2 ATP
• Anaerobic glycolysis


  Glucose --> 2 molecules of pyruvate --> 2 molecules of ATP (net) --> 2 NADH