L5 - PA Guidelines & Measuring PA

• Leading Causes of Death:

  • Biggest killer in NZ flips in between cancer & cardiovascular disease (CVD)
  • In 2015 was cancer, killed 10,000
  • In 2019 CVD killed just over 10,000, cancer just short of that
• Main causes of death of the Māori population in NZ

  • Slightly different for Māori population
  • Cancer more prevalent
• Cardiovascular disease is the leading cause of death worldwide:

  • Mortality stats not the same across the world
  • Differences between ethnicities, SES, countries etc
  • High income countries cancers cause more deaths (x2 as much as CVD)
  • Middle-low income countries CVD is more prevalent
• What are the health benefits of PA?

  • All cause mortality by 30%
  • Cardiovascular disease by up to 35%
  • Type 2 diabetes by up to 40%
  • Colon cancer by 30%
  • Breast cancer by 20%
  • Depression by up to 30%
  • Hip fractures by up to 68%
  • Dementia by up to 30%
  • PA is important
• PA & All Cause Mortality:

  • If do PA you reduce risk of dying
  • Vigorous activity → massive reduction
  • Need to do more duration at lower intensity for same benefit
• TV viewing & All Cause Mortality:

  • More TV you watch, you increase risk of dying
• Cardiorespiratory fitness (CBF):

  • CBF reflects the ability to transport oxygen to the mitochondria (throughout body) to perform physical work & is used to quantify functional capacity (how much can we do) of an individual
  • Decreases as you age; why have age related disease
  • Body less good at getting & using oxygen
• Cardiorespiratory fitness (CRF);

  • Clearly, CBF is directly related to the integrated function of numerous systems, & considered a reflection of total body health
  • 15-18 ml O2/kg/min is the maximum to sustain independence → clinically important vital sign
  • If below high chance they can’t live independently
• Modifiable Risk Factors:

  • How can we reduce risk of dying other than just PA
  • Improve lifestyle by changing modifiable factors/lifestyle changes
  • PA is not enough on its own
• Modifiable Risk Factors:

  • When thinking about holistic/whole individual to getting more healthy have to think about other factors
  • eg smoking, excessive alcohol use, unhealthy diet, physical inactivity
  • Environmental risk, kind of but more involved in it
• Modifiable Risk Factors:

  • We can suggest lifestyle changes, if require more help may need to refer them; know enough of why smoking etc is bad can try educate them
  • Probably best to refer to dietician or someone else for alcohol use
• Many different Guidelines:

  • Heaps of different “guidelines”
  • What do we really need to do; these are unhelpful
• WHO: PA Guidelines for Adults (18-64 yrs old) = most used/universally agreed

  • PA includes recreational or leisure-time PA, transportation (eg walking or cycling), occupational (ie work), household chores, play, games, sports or planned exercise, in the context of daily, family, & community activities
• WHO: PA Guidelines for Adults (18-64 yrs old) = most used/universally agreed

  • In order to improve cardiorespiratory & muscular fitness, bone health & reduce the risk of NCDs & depression the following are recommended
  • Adults aged 18-64 yrs should do at least 150 mins of moderate intensity aerobic PA or at least 75 mins of vigorous intensity aerobic fitness PA throughout the week, or an equivalent combination of both
• WHO: PA Guidelines for Adults (18-64 yrs old) = most used/universally agreed

  • Aerobic activity should be performed in bouts of at least 10 mins duration
  • For additional heath benefits, adults should increase their moderate intensity aerobic PA to 300 mins per week, or engage in 150 mins of vigorous intensity aerobic PA per week, or an equivalent combination of moderate & vigorous intensity activity
• WHO: PA Guidelines for Adults (18-64 yrs old) = most used/universally agreed

  • Muscle strengthening activities should be done involving major muscle groups on 2 or more days a week
  • Note: these guidelines are universally agreed & include the AHA/ACSM
• NZ PA Guidelines for Adults:

  1. Sit less, move more! Break up long periods of sitting
  2. Do at least 2 ½ hrs of moderate or 1 ¼ of vigorous PA spread throughout the week
  3. For extra health benefits, aim for 5 hrs of moderate or 2 ½ hrs of vigorous PA spread throughout the week
  4. Do muscle strengthening activities on at least 2 days each week
  5. Doing some PA is better than doing none
• Found all those guidelines are just picked out of the air → NO evidence of improving health at a population level
• How much PA is enough?

  • Use critical thinking
  • Educate them
  • Keep in mind they are just guidelines NOT rules
  • Can use those guidelines as long as still critically think why you are doing something
  • Why are you prescribing something? & explain why you are doing something (not just cause that’s the guidelines)
• Optimal Dose-Response:

  • The relationship between the characteristics of the activity performed & the nature of the health-related changes produced
  • Duration, Frequency, Intensity → Optimal Activity + (Minimal time + Minimal effort) = Minimal medical risks/Minimal time & effort + Greatest Health Benefits
• Optimal Dose-Response

  • Optimal activity dose varies
  • For different health benefits
  • For different individuals
  • Key message: different for everyone, no one size fits all exercise-prescription → because everyone is different (background, interest, support systems)
• Principles for Dose-Response

  • 3 key exercise changing principles

  1. Overload
  2. Progression
  3. Specificity

  • Safe progression aligned with overload to increase capacity & how to make it specific to achieve their goal
• Overload Principle:

  • When a muscle tissue/system is stressed by an increase PA
  • Have to do something that is new for your body; duration, frequency, intensity, activity
  • Respond by increasing your capacity (if frequent, chronic)
  • Stress → adaptation
• Progression Principle:

  • Don’t want injury
  • Increase in small amounts & at low intensity
  • Keep increasing bodies capacity without injury
  • Also includes frequency
• Specificity Principle:

  • Specific types of changes in body when start exercise, depends on characteristics of specific activity
  • Specific to nature & degree that activity demands from the body
  • eg arm vs leg exercise
  • What do you want to improve/the outcome you are wanting to achieve
• Principles for Dose-Response:

  • Know what to think about when prescribing (principles, guidelines)
  • But how we going to measure that
• Measuring physical activity/fitness

  • Job classification
  • Leisure-time activity
  • Questionnaire
  • Pedometer
  • Accelerometer
  • Wearable technology
  • Fitness
  • Direct VO2 max (treadmill or cycle ergometer)
  • Predict VO2 max from sub-maximal HR
  • Functional measure, eg time to exhaustion, once achieved, level in shuttle walking test
  • Measure what you want to know/improve
  • These measurements good for overall PA, to get PA baseline
• Quantifying physical activity/fitness

  • Metabolic equivalent of task (MET level)
  • Sitting quietly = 1 MET (resting metabolic rate)
  • Light, <3.0 METs;
  • Moderate, 3.0-5.9 METs ;
  • Vigorous, >6.0 METs
  • METs are equal to the ratio of the activity metabolic rate to the resting metabolic rate
  • Energy expenditure for each activity (kilocalories)
• METs:

  • Guidelines not proven, specific level of MET-mins per week is useful way to calculate energy expenditure
  • Several health benefits associated with regular PA practice, contributed by intensity
  • Important to determine intensity; can on HR but METs better → working metabolic to ratio of exercise metabolic
  • When accessing intensity using METs
• METs per minute:

  • Guidelines: 500-1000 MET-minutes per week for significant health benefits
  • Not associated with 150 mins
• METs per minute:

  • To calculate MET minutes you need:
  • MET value of an activity
  • The duration of the activity (in mins)
• METs per minute examples:

  • Walk 2 days a week at 5 METs for 30 mins per session = 300 MET-minutes
  • Bike 1 day a week at 7 METs for 20 mins = 140 MET-minutes
  • Elliptical machine 2 days a week at 6METs for 40 mins = 480 MET-minutes
  • Total MET-minutes for the week: 920 MET-minutes; within those guidelines
  • Don’t need to remember METs for each activity
• Key Points for PA Advising:

  • Significant health benefits achieved by meeting minimal PA guidelines
  • The more activity the better
  • Duration more important than intensity
  • PA can be accumulated in 10 min increments
  • Strength & flexibility exercises
  • esp at older ages
  • Greatest health benefits occur when inactive individuals begin modest regular PA
  • Furthest away from ceiling
  • Lifestyle activities more likely to be sustained than structured activities
  • Do strategies that they like; more enjoy it more will do it
• Activities of Daily Living:

  • Activities of daily living such as homework are usually light PA (<3 METs)
  • Often not included in guidelines
  • Great way to reduce sitting time
  • Is better than nothing
  • Although these activities will not be enough to meet the recommended 2 ½ hrs of moderate PA each week, will provide some benefits to overall health
  • Importantly, activities of daily living can replace sitting time
  • Prescribe in a way that is fun
• Keep PA Fun & Varied:

  • Try to make PA fun & sustainable as this makes regular participation more likely (esp when doing it for longer)
  • Change routes & routines to help avoid boredom
  • Use walking tracks, parks & hills or try a new PA or sport
  • Swim at the beach or the river
  • Walk with family/friends, may gain even more benefit when they do it with others
  • Break up PA into smaller, more manageable chunks (known as ‘snacktivity)
• Relationship between PA & Health:

  1. PA → Health; PA is associated with health benefits
  2. PA → Fitness → Health; effects of PA on health are mediated by increase in fitness
  3. PA + Fitness + Health = All affect each other; PA & fitness are positively associated with health & healthy individuals are more inclined to be PA

  • Becomes a vicious cycle