Physical Activity Flashcards
Is Physical Activity and Exercise the same thing?
No
What is physical activity?
Any bodily movement produced by skeletal muscles that requires energy expenditure
What is exercise?
- A subcategory of physical activity
- Planned, structured, repetitive and purposeful in the sense that the improvement or maintenance of one or more components of physical fitness is the objective
How do we measure physical activity (from most precise to least)?
- Direct calorimetry
- Doubly labelled water
- Indirect calorimetry
- Heart Rate
- Movement sensors
- Self reporting
(The more precise, the harder to assess)
What are the components of physical activity?
- Measured in metabolic equivalents (METs)
- Sedentary behaviour = <1.5 METs
- Light PA = 1.5 to 3 METs
- Moderate to vigorous PA = >3 METs
What are the 7 population groups of the WHO physical activity and sedentary behaviour guidelines?
- Children and adolescents
- Adults
- Pregnant and postpartum women
- Older adults
- Adults with chronic conditions
- Children, adolescents and adults living with disability
What is recommendation 1?
- At least 150 to 300 minutes moderate-intensity aerobic physical activity OR
- At least 75 to 150 minutes vigorous aerobic physical activity
- This is a strong recommendation with moderate certainty evidence
What are the health outcomes of physical activity in adults?
Improved:
- All cause mortality
- Cardiovascular disease mortality
- Incident hypertension
- Incident site specific cancers
- Incident type 2 diabetes mellitus
- Mental health
- Cognitive health
- Sleep
What is the evidence for recommendation 1?
- Dose response relationship indicates there is no lower threshold for health benefits
- There is limited evidence to identify the exact point at which the harms of PA out weigh the benefits
- The health benefits seem to plateau towards the upper end
What is recommendation 2?
On a least 2 days a week, muscle-strengthening activities at moderate or greater intensity that involve all major muscle groups
What is the evidence for recommendation 2?
- 0.80 which means 20% less risk of mortality
- P-value is really low (0.001) which means its very significant (not due to chance)
What are good practice statements?
- Doing some PA is better than doing none
- If adults are not meeting these recommendations, doing some PA activity will benefit their health
- Adults should start by doing small amounts of PA, and gradually increase the frequency, intensity and duration over time
What is physical inactivity defined as?
Not doing at least 150 minutes of moderate intensity or 75 minutes of vigorous intensity physical activity per week, or any equivalent combination of the two
Is physical inactivity the same as sedentary behaviour?
No
What is physical inactivity?
Accruing insufficient physical activity to meet activity guidelines
What is sedentary behaviour?
Any waking behaviour characterised by an energy expenditure <1.5 METs, while in a sitting, reclining or lying posture
What do the observational studies tell us about sedentary time and health?
Increased breaks in sedentary time have been associated with improved measure of body composition improved postprandial plasma triglyceride and glucose responses
What do the experimental/lab-based studies tell us about sedentary time and health?
Breaking up sedentary time with exercise has been associated with improved postprandial glucose and insulin response
What is recommendation 3?
- Limit the amount of time spent being sedentary
- Replace with more physical activity of any intensity
What should future research look into?
- The health benefits of light PA
- The health benefits of breaking up sedentary time with light PA
- Differences in the health effects of different domains of PA
- Joint association of PA and sedentary time on health, over the life course
What is the SuNDIAL study?
- Nationwide, cross-sectional survey
- Two sub-studies: 2019: female adolescents, 2020: male adolescents
- Schools from around the country were invited to participate
- 401 participants from 19 schools were included in analysis
How did COVID-19 impact the data collection of the SuNDIAL study?
In person data collection quickly switched to virtual after lockdown commenced:
- 24h diet history
- Physical activity 2h recall
How did COVID-19 impact the physical activity data of the SuNDIAL study?
Only a small number of male participants completed accelerometery (PA data collection)
What were the results of the SuNDIAL study?
- Only 114 participants provided enough data to be included
- 7h 17min: average time in sleep, per day
- 11h 51min: average time spent sedentary, per day
- 3h 40min: average time in low PA, per day
- 42min: average time in moderate to vigorous PA, per day
What were the main findings in regards to the guidelines in the SuNDIAL study?
Overall, 24% of participants met the PA guidelines
What were the main findings in regards to active commuting in the SuNDIAL study?
Those who used AT accumulated an additional 12 min/d of MVPA
What were the main findings in regards to organised sport in the SuNDIAL study?
Those who participated in sport accumulated an additional 17min/d of MVPA
What were the main findings in regards to all three domains in the SuNDIAL study?
For every additional domain of PA, participants had additional LPA, MVPA and less sedentary time
What are the domains of physical activity?
- Majority of female adolescents are not meeting the PA guidelines
- Targeting a combination of domains has the potential to increase PA in this population
