active transportation and sedentary behaviour Flashcards
obeseogenic environment
walking/cycling/cars and obesity
one US study found that men who walk or cycle to work were half as likely to be obese
another found that every kilometer walked per day is associated with a 4.8% reduction in obesity. every additional hour spent in a car each day is associated with a 6% increase in the likelihood of obesity
active transport
bicycle is cheapest, healthiest and fastest way to get around a city
also reducing carbon emissions
investing in bike lanes
New York built 45.5 miles of bike lanes in 2015, with an investment of about $8 million
this increased the probability that residents would ride a bike by 9 percent
every $1,300 New York City invested in building bike lanes in 2015 provided benefits equivalent to one additional year of life at full health over the lifetime of all city residents
which is a good return on investment than some direct health treatments, like dialysis, which costs $129,000 for one year
pedelecs as a physically active transportation mode
by peterman et al.
participants ride e-bike at least 3x week, 40 mins a day over 1 month
GPS trackers and heartrate monitor
results: after a month, health tests showed the subjects had better cardiovascular health, more aerobic capacity, and improved blood sugar control compared to before
significantly higher VO2 max and maximum power output
signficantly lower glucose levels
pedelecs are an effective form of active transportation within only 1 month
overview of cycling research
by cavacuiti
according to data from the Canadian Vital Statistics: Death database (CVSD), between 2006 - 2017, 890 cyclists died in Canada, an average of 74 deaths per year. Over the same period, the age-standardized cycling death rate decreased from 2.5 in 2006 to 1.3 deaths per 1,000,000 population in 2017
bike boxes
bike boxes are marked spaces at intersections that indicate dedicated areas where cyclists can wait when stopped at an intersection.
they can facilitate left hand turns and improve visibility of cyclists
markings through intersections
increases cyclist visibility, creates more space for them on the road and through intersections
protected bike lanes
increases safety, quickest way to implement is to install inexpensive and removeable plastic bollards
condos scramble to create bicycle storage space
by frantz
improved safety: increasing the number of cyclists on your streets can save lives, leading to a reduction in the rate of collisions between motorists and bicyclists and walkers
cycling rates soared since the early 1990s while the crash risk per rider dropped by about 70%
CO2 emissions bike vs car
by european cyclists federation (ECF)
even with the CO2 emissions of food required to power a bicycle, the ECF study found the bicycle is the lowest emitter of greenhouse gasses per passenger kilometer traveled
emissions from cycling are over 10x lower than those from the passenger car
western university biking environment
- cycling network linking the campus to surrounding areas is incomplete
- inadequate bike lanes and parking (covered and secured lockers)
- no bike sharing program
- no rapid transit link
- no innovative technology
what is sedentary behaviour?
- any waking behaviour characterized by an energy expenditure of less or equal to 1.5 metabolic equivalents (METs) while in a sitting or reclining position
one MET is defined as 1 kcal/kg/hour and is roughly equivalent to the energy cost of sitting quitely.
a MET is also defined as oxygen uptake in mL/kg/min with on MET equal to the oxygen cost of sitting quitely, equivalent to 3.5 mL/kg/min
METS and other PA intensities
tremblay et al
sedentary behaviour
- much of our sitting is for work or school
examples:
- using computer for work or school; riding in a car; studying; sitting in class
historical perspective - sitting and health
- first evidence that inactivity is bad for you was published in the Lancet by Morris et al in 1953
- included in their seminal work was an ecologic study of heart disease mortality and occupational physical activity
does physical activity attenuate, or even elimate, the association of sitting time with mortality? meta-analysis
by ekeland et al
in addition to promoting reductions in sedentary behaviours, these results indicate that a strong public health focus should remain on increasing levels of MVPA, irrespective of the amount of time people spend sitting in a day. individuals who are forced to sit throughout the day because of educational or occupational constraints should aim for the high end of the MVPA recommendations, not the low end
health consequences of sedentarism
compromises - bone mineral density and vascular health
risk factor for - obesity and some cancers
how strong is the association?
- best evidence comes from systematic reviews which summarize the findings of numerous studies
- systematic review: Wilmot et al. sedentary time in adults and the association with diabetes, cardiovascular disease and death
findings: compared greatest sedentary time to lowest
irrespective of physical activity level, those who spent the most time sitting were more than two times more likely to have or develop diabetes
almost twice as likely to die of cardiovascular disease
one and a half times more likely to die over the course of the study
age and sedentary behaviour
negative effects of sitting are seen among all age groups
acute effects among young adults
by hamburg et al.
reduced metabolic health after 5 days of bed rest in healthy young adults
sedentary control groups
by kraus et al
metabolic responses to reduced daily steps in health nonexercising men
by olsen et al.
participants were to reduce daily steps
findings: plasma insulin goes up
telomere
a telomere, the highly repetitive end segment or terminator of a DNA chain that functions as a cap
telomeres stop chromosomes from fraying, clumping together and scrambling genetic code - lifespan is linked to their length
scientists found the less time people spend sitting, the longer their telomeres
measuring free living PI and PA
sensor -> picks up the amplitude and frequency of movement -> produces an electrical current of various magnitude (more intense the movement the greater the voltage)
stores the information as activity counts - converted to AEE/METs based on default or predetermined cut points
“active couch potato”
an individual who meets physical activity guidelines but spends most of the day being sedentary
physical activity of Canadian adults: accelerometer results (2007-2009)
15% adults accumulate 150 minutes of moderate to vigorous PA per week
Grade - F
why getting people to exercise more has failed
exercise is not enjoyable
people do not see immediate benefits from exercise
exercise is often thought of as activity you do at a special facility
people don’t want to make time for exercise
exercise may lead to compensatory behaviour
why getting people to sit less may be easier
sitting less is not unpleasant (mostly)
strategies for sitting less can be implemented at any time and almost any place
extra time doesn’t have to be made for sitting less
sitting less leads to more incidental PA
incidental PA is easier to do than MVPA (moderate-vigorous physical-activity) for most people
calorie
a calorie is the energy needed to raise 1 gram of water up 1 °C
how to reduce your risk
interrupt all sedentary behaviour with frequent breaks
breaks in sedentary time
decreases:
- waist circumference
- systolic blood pressure
- glucose
- insulin
- triglycerides
increases:
- HDL-cholesterol
the effectiveness of breaking up sedentary behaviour
by dunstan et al.
breaks improve glucose levels and insulin levels
a-smartphone-based intervention to reduce sedentary time in overweight/obese individuals
by bond et al.
intervention: 3 min breaks after 30 mins of sitting
results: 47 min reduction from 593 min of daily sitting (6% reduction)
conclusion: the smartphone-based intervention significantly reduced SED. Prompting frequent short activity breaks is an effective way to decrease SED. Future work should determine whether these SED reductions can be maintained long-term
evaluation of sit-stand workstations in an office setting
by graves et al.
conclusions: short-term use of a sit-stand workstation reduced daily sitting time and led to beneficial improvements in cardiometabolic risk parameters in office workers.
if continued long-term, it may reduce cardiometabolic risk in a large proportion of the working population
increasing nonsedentary behaviours in University Students using text messages
by cotton & prapavessis
why text messages? widely accessible, able to control when participants recieve messages, proven to work with other health behaviours
aim: the effectiveness of text messages as a way to reduce sedentary behaviour in uni students
increase self-efficacy and break behaviour
intervention: mix of challenges, facts and reminders sent twice daily
control: random health/food facts and tips
results: intervention group improved in all behaviours, self-efficacy cognitions correlated well with target behaviours
limitations: subjective measure of sedentary behaviour, small sample, short term
keypoints
sedentary behavior is a major health problem
sedentary behavior vs PA behavior are distinct (being a regular exerciser does not make up for the negative effects of too much sitting)
guard against compensation
change the way you conduct your everyday business (stand more, engage in more incidental PA or non-exercise activity thermogenesis-NEAT)
change your home and work environment to sit less (getting up every 30 mins can improve risk profile)
use your voice to promote a sit less community (city planning and policy)
the Public Health Message should focus on reducing sedentary behavior NOT increasing MVPA (moderate-vigorous physical activity)
