L2 - Intro to PA & Health

• What is physical activity?

  • Any bodily movement produced by contraction of skeletal muscle that substantially increases energy expenditure above resting metabolic rate (RMR)
• Energy expenditure associated with PA typically only 25% of daily energy expenditure, athlete can go up to 50%
• PA Characterised by:

  • Modality
  • Frequency
  • Intensity
  • Duration
  • Context of practice
  • Also used for exercise prescription (ExRx)
• PA Categories:

  • Leisure time PA
  • Exercise
  • Sport
• PA Categories - Leisure time PA:

  • An activity undertaken in the individual’s discretionary time that increases the total daily energy expenditure
• PA Categories - Sport:

  • Sub category of leisure time & exercise
  • Is part of the PA spectrum & corresponds to any institutionalised & organised practice, reined over by specific rules
• PA includes:

  • Leisure time
  • Exercise
  • Sport
  • Occupational PA
  • Other chores PA
  • Active transport
  • Household related PA
• Physical fitness defined as:

  • The ability to perform muscular work satisfactorily
  • No universally agreed definition of fitness & its components
  • Fitness defined on 2 goals:

  1. Performance
  2. Health → most of population
• Performance-related fitness:

  • Components of fitness essential for sport performance
  • Muscle strength, speed, agility etc
• Health-related fitness:

  • Components of fitness that benefit from a PA lifestyle & relate to health
  • Ability to perform daily activities
  • e.g. standing, walking, chores etc
• Health-related physical fitness components:

  • Cardiorespiratory endurance
  • Body composition
  • Muscular strength
  • Muscular endurance
  • Flexibility
• Cardiorespiratory endurance = the ability of the circulatory & respiratory system to supply oxygen during sustained PA
• Body composition = the relative amounts of muscle, fat, bone & other vital parts of the body
• Muscular strength = the ability of muscle to exert force
• Muscular endurance = the ability of muscle to continue to perform without fatigue
• Flexibility = the range of motion (ROM) available at a joint
• Skill-related physical fitness components:

  • For performance
  • Agility
  • Coordination
  • Balance
  • Power
  • Reaction time
  • Speed
• Agility = the ability to change the position of the body in space with speed & accuracy
• Coordination = the ability to use senses, such as sight & hearing, together with body parts in performing tasks smoothly & accurately
• Balance = the maintenance of equilibrium while stationary or moving
• Power = the ability or rate at which one can perform work
• Reaction time = the time elapsed between stimulation & the beginning of the reaction to it
• Speed = the ability to perform a movement within a short period of time
• Health-related fitness components:

  • Morphology
  • Cardiorespiratory
  • Muscular
  • Motor
  • Metabolic
• Morphology:

  • Muscle mass
  • Subcutaneous fat distribution
  • Abdominal visceral fat
  • Bone density
  • Really important especially in older adults
• Cardiorespiratory:

  • Submaximal exercise capacity
  • Don’t need max in general population
  • Maximal aerobic power
  • Heart functions
  • Lung functions
  • Blood pressure
• Muscular:

  • Power
  • Strength
  • Endurance
  • Flexibility
• Motor:

  • Agility
  • Balance
  • Coordination
  • Speed of movement
• Metabolic:

  • Glucose tolerance
  • Insulin sensitivity
  • Lipid & lipoprotein metabolism
  • Substrate oxidation characteristic
• Population-attributable risk:

  • The proportion of cases of a disease or outcome in a population that can be attributed as a particular risk factor
• The health burden of physical inactivity:

  • Physically inactive = if not meeting PA guidelines
  • eg 150 min of moderate PA a week
  • Is the biggest killer (influences NCD)
• Physical inactivity = the non-achievement of PA guidelines
• Sedentary behaviours = any waking behaviour characterised by an energy expenditure (EE)<1.5 METs while in a sitting, reclining or lying position
• What is health:

  • WHO: a state of complete physical, mental & social well-being & not merely the absence of disease or infirmity
  • Is hard to define, so many factors that influence it (multifactorial)
• Life Expectancy (LE) stats:

  • Global LE has risen 7 yrs since 1990
  • Have an ageing population =
  • can be explained by increased LE
  • New problem
  • Longer life has advantages, but only way to enjoy it is if you’re healthy
  • PA to be healthier for longer
• Life Expectancy = how long expected to live before restrict activities → where PA comes to help
• Chronic diseases include:

  • Heart disease
  • High blood pressure
  • Diabetes
  • Cancer
  • Obesity
  • Asthma
• Clinical conditions include:

  • Genetics
  • Behaviour
  • Physical environment
  • Social environment
• Chronic diseases:

  • Most serious public health burden
  • A lot of individual difference including genetics etc
  • CD are largely preventable
  • Smoking, poor diet, excessive alcoholism
  • Low SES - economically disadvantaged & are at greater risk
  • Other important factors:
  • Limitations in health care system, medical errors
  • Those out of their control
  • More than ½ experienced by older people, avoidable by early lifestyle changes
  • Lifestyle changes can reverse/reduce them, better to prevent
  • GP’s easier to prescribe treatment that work thru them on lifestyle changes