Sedentary behaviour Flashcards

1
Q

the whole proposition of the sedentary behaviour class?

A

sedentary behavior (too much sitting) is a deeply-embedded public health problem, which is additional to lack of physical activity (too little exercise)

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2
Q

what is a confounder?
- what are confounders for sitting too much being a risk factor for all-cause mortality?

A
  • a variable that correlates with both x and y –> causes confusion in true relationship
  • sex, age, genetics, diet, environment (climate), job, family income, neighbourhood safety, rich vs low income, level of PA
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3
Q

what does it mean if something is an independent risk factor?

A

means that even if we control for all the other confounding variables, there is sill an association btw x and y
- ie: sitting is a risk factor for all-cause mortality, independent of levels of PA –> even if you control for PA, still an association btw sitting and mortality

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4
Q

how to establish sedentary behaviour ish? vs light vs moderate
- goal of public health PA guidelines?

A

using METs!
0.9 = sleeping
1.0 - 1.8 = sedentary
- 1.0 = sitting quietly (TV viewing)
- 1.5 = sitting (talking)
- 1.8 = sitting (desk work
2.0 - 3.0 = light
- 2.0 = standing
- 2.5 = slow walking
> 3.0 = moderate
- 3.8 brisk walking

  • increase time spent in mod-vigorous activity!
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5
Q

how to apply public health framework to sedentary behaviour research?
4 steps ish

A
  1. epidemiology: tracking PA (time surveys) vs sedentary and look at health outcomes –> see if there is an association
  2. if there it, generate hypothesis –> which leads to clinical/interventional: sample people, check blood work and BP + sedentary + PA levels vs health outcomes
  3. if you still see a trend, measure effectiveness/efficacy of intervention –> how to decrease risk factors –> change/modify PA levels and sedentary levels –> see if effect on health outcomes
  4. translational –> how to get the word out? implement public health policy and programs to improve the health outcome

*still early days for sedentary behaviour research (vs domains for PA)

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6
Q

canadian sedentary behaviour guidelines for children 5-11 yo (3 ish)

A

*1st country in world to come up with sedentary behaviour guideline!

  • should minimize time spent being sedentary each day by:
    1. limiting recreational screen time to no more than 2h per day –> lower levels associated with additional health benefits
    2. limiting sedentary (motorized) transport, extended sitting and time spend indoors throughout the day
    *encourage active and outdoors activities!
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7
Q

what counts as being sedentary for children? (5)

A
  • sitting for long periods
  • using motorized transportation (bus/car)
  • watching television (electronic babysitter)
  • playing passive video games
  • playing on computer
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8
Q

spending less time being sedentary can help children do what (6)

A
  • maintain healthy bw
  • do better at school
  • improve self-confidence
  • have more fun with friends
  • improve their fitness
  • have more time to learn new skills
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9
Q

what are 3 things to help children swap sedentary time with active time?

A
  • active transportation (vs driving to school) –> walk to school with groups of kids from neighbourhood
  • active play (vs TV) (ie after school) –> limit after school TV watching. plan time outdoors instead + encourage kids to participate in sports
  • active family time: instead of video games, introduce family to active games
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10
Q

what objective measurement is changing the research frame in sedentary behaviour? describe

A

accelerometers!
- Activ graph: small, lightweight, unobtrusive –> can record time, duration, frequency and intensity (light vs mod-vig) of mvt in one-minute epochs
- Activ pal: very good for measuring sedentary time (sitting/lying) + number of transitions btw sitting and standing (reduced for very sedentary people)

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11
Q

NHANES sedentary time in US population –> what is the trend as age increases for time spent in sedentary behaviour?

A

sedentary behaviour increases!
- lowest = 6-11 yo
- highest = 70-85 yo
BUT 12-15 and 16-19 have higher time than 20-59!

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12
Q

what is the adult’s overall daily behaviour patterns distributed btw physically active and sedentary time? (pie chart)

A
  • 9.3h sedentary time (sitting, studying, in class…)
  • 6.5h light-intensity activities
  • 0.7h mod-vig intensity activities
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13
Q

describe modern sitting-oriented society

A
  1. wake up (7am)
  2. 15min sitting breakfast + 45min transport to work sitting in car/traffic
  3. work 3.5h + lunch sitting 30min + work sitting 4h
  4. transport back home sitting (45min) + 30min dinner sitting
  5. 4h watching TV + maybe walk 30min
  6. sleep 11pm

from 2 to 5 –> 15.5h of sitting opportunity…

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14
Q

trends (from 1981 to 2002) in households with entertainment equipment that promotes too much sitting (describe graph)

A
  • VCR/DVD (from 1981), computer (from 1986) and internet (from 1996) increase from 10% to 60% ish throughout the years
  • one TV at 70% in 1981, decrease to 30% in 2002
  • 2+ TV from 55% in 1981, increase to 90% in 2002
  • cable TV from 70% in 1991 to >90% in 2002
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15
Q

prevalence of overweight children vs hours of tv watched per day: describe graph (boys vs girls)

A

more overweight children as hours of TV watched per day increases!
- <1h/day = around 20% obesity prevalence (more boys than girls)
- 2-3h = 25-30% (more boys than girls)
- >4h = 30-35% (more girls than boys)

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16
Q

sum of 4 skinfolds (adiposity) vs daily television watching habit in children –> describe graph

A

significantly leaner from 4+ h to 2-3h to <2h
- girls have higher sums than boys for all 3 categories

17
Q

sum of trunk skinfolds in boys vs thirds of vig activity vs thirds of television watching (staireogram) –> describe!

A

worst sum = high TV watching and low vig activity
- best = low TV and low vig activity (weird but thats what the graph shows)

18
Q

what is the trend for television viewing over the years? 2 studies

A

TV viewing time increases (from 4.5h per day in 1950 to around 8h per day in 2000) in US
- increases from 1.8h (women) and 2.0h (men) in 1992 to 2.0 (women) and 2.6 (men) in 2006. in Australia

19
Q

avg weekly time spend watching TV in canada –> which 2 groups spend the most time?

A

18+ yo = around 27h per week
55+ yo = around 39h per week!
- all other ages around 13-17h ish

20
Q

how is screentime ish separated? (pie chart)

A

153.2 watching TV
8.1 watching time shifted (recorded TV)
29.2 time on Internet
3.4 watching videos on mobile phone
3.1 watching video on internet
in 2012

21
Q

what questions are asked for self-reported PA and TV time? from AusDiab Measures: Active Australia. (4)

A

self reported PA:
- how many times have you walked continuously for at least 10min, in last week?
- what do you estimate was total time spend walking in last week?

self-reported TV time:
- estimate total time last week spent watching TV or videos when it was the main activity –> options for Monday to Friday + Saturday and Sunday

22
Q

odds of metabolic syndrome
- men vs women

A

MEN:
- highest (bit below 2x odds) when > 14h TV/week and <2.5h PA/week
- lowest (1x odd) = <14h TV and >2.5hPA
WOMEN:
- - highest (3.5x odds) when > 14h TV/week and <2.5h PA/week
- lowest (1x odd) = <14h TV and >2.5hPA
- low TV + low PA –> still 2x risk
- high TV and low PA also 2x risk ish

23
Q

cross-sectional and longitudinal studies: high TV time (how many hours) is detrimentally associated with (2), independent of what?

A
  • high TV time (2-4+h per day) –> associated with biomarkers and health outcomes, independent of leisure-time PA
24
Q

high TV time is associated with which 6 health outcomes?

A
  • CVD risk
  • overweight
  • diabetes
  • metabolic syndrome
  • abnormal glucose metabolism and other biomarkers of cardio-metabolic health
  • cancer
25
Q

Canada fitness survey 12-year mortality follow-up 1981-1993
- difference btw physically inactive vs physically for sitting almost all the time, 3/4 of time, 1/2 of time, 1/4 of time, almost none of the time
describe graph!

A

PHYSICALLY INACTIVE
- almost none of the time and 1/4 of time has lowest age-adjusted all-cause death rate
- then increases pretty linearly with almost all the time having highest all time mortality
PHYSICALLY ACTIVE
(>=7.5 MET-hr/week)
- same trend as physically inactive (increasing death rate as sitting time increases but “none of the time” starts a bit lower and “almost all the time” is at same level as 1/2 of time ish of physically inactive
- not as pronounced but still a significant trend!

26
Q

meta-analysis
1. level of sitting vs hazard ratio/all-cause mortality –> relationship?
2. level of TV viewing vs hazard ratio

A
  1. increase level of sitting = increase hazard ratio, pretty linearly, but some studies see an inverse relationship
  2. gradual increase despite a few abnormalities. less data than (1), one of the studies has a really big upwards slope
    *level of TV viewing = the most risky of sedentary behaviour of all sitting bc associated with more food and alcohol consumption
27
Q

which health outcomes have a strong level of evidence of association with sedentary behavior?
- what about strong level of evidence for dose-response?

A
  • all-cause mortality, cardiovascular disease mortality, incident type 2 diabetes, incident cardiovascular disease (VS cancer mortality and weight status = limited, incident cancer = moderate)
  • all-cause mortality, cardiovascular disease mortality, incident cardiovascular disease
28
Q

describe heat map of risk of mod-vigorous PA vs daily sitting time
- how is risk of all-cause mortality depicted?

A
  • risk of all-cause mortality is depicted by the color! risk decreases as one moves from red to green
  • low PA + low sitting time –> orange/yellow = not good
  • low PA + high sitting time = very red = very bad
  • as you move towards the right (increase PA), becomes more yellow and green
  • BEST = high PA and low sitting
  • high PA and high sitting = light green = get protection from high PA
29
Q
  • strong evidence demonstrates that association btw sedentary behaviour and all-cause mortality varies by amount of ____WHAT_____, such that hazardous effects of sedentary behaviour are more pronounced in ________ _________ people
  • moderate evidence indicates that effect of ________ vary by amount of sedentary behavior –> explain
  • individuals who are highly sedentary need what to achieve same level of absolute mortality risk as people who are less sedentary?
  • CONCLUSION?
A
  • varies by amount of mod-vigorous physical activity –> are more pronounced in physically active people
  • effects of MVPA vary by amount sedentary behaviour –> those who are the most sedentary experience the greatest relative reductions in mortality risk associated with increases in PA
  • highly sedentary –> require even higher amounts of PA to achieve the same level of absolute mortality risk as people who are less sedentary
  • therefore, MVPA should be part of every adult’s lifestyle, especially for those who sit for large portions of the day
30
Q

can you be active but also highly sedentary?

A

yes!
example of accelerometer data for a week –> mean mod-vig time = 31min/day + 71% of waking hours spend in sedentary

31
Q

difference btw active couch potato and active non-couch potato
- define both

A

ACTIVE couch potato:
- mod-vig PA meeting guidelines considered physically active BUT also high level of sedentary behaviour
- activity during the day, but rest of time, METS are btw 1 and 2 = sedentary
ACTIVE NON-COUCH POTATO:
- similar level of mod-vig PA but less sedentary behaviour
- activity during day but rest of time, between 2 and 3 METS –> maybe standing, or takes breaks from sitting

32
Q

difference between prolonger and breaker?

A

prolonger:
- long periods of time where sedentary time <100 counts/min (dark band) and some huge chunks of nonsedentary time (>100 counts/min) (light)
- big chunks
BREAKER:
- a lot of alternating between dark and light bands
*even if sedentary time is the same, ppl who have breaks have better health outcomes

33
Q

which 4 health outcomes/blood markers are more elevated for people in first 2 quartiles of breaks in sedentary time?

A
  • waist circumference
  • body mass index
  • triglycerides (log)
  • 2h plasma glucose

*all higher for first 2 quartiles vs Q3 and Q4 which are decreased

34
Q

2 bottom-line conclusions from too much sitting

A
  1. reducing and/or breaking up sitting time must now be considered as a potential public-health priority
  2. this is additional to (and not an alternative to) participation in moderate intensity physical activity (because sedentary behaviour is independent to PA)