Unit 3: What are the benefits of physical activity?
you are hardy if you have these three traits
- a sense of personal control over external events - a sense of involvement, commitment, and purpose in daily life - the flexibility to adapt to unexpected changes by perceiving them as challenges or opportunities for further growth
Epidemiology an in depth look
- basic science of public health - highly quantitative discipline based on statistics and research - applied to the whole spectrum of health-related events, includes chronic disease, environmental and behaviour problems, and injuries in addition to infectious disease. - deals with GROUPS of people rather than the INDIVIDUAL
Baby boomers have more what than the previous generation? (re: Health) from Video
- chronic disease -obesity -lower self rated health
Advantages to cohort studies
- examine multiple outcomes for a single exposure - useful in examining rare exposures (ex. lung cancer or asbestos) - you can directly calculate the incidence of diseae for each of the exposure groups - the temporal sequence is logical
physiological explanations why exercise may have a positive effect on wellbeing
- increases in cerebral blood flow - changes in brain neurotransmitters -increases in maximal oxygen consumption and delivery of oxygen to cerebral tissues -reductions in muscle tension -structural changes in the brain
benefits of exercise (half an hour to an hour)
- knee arthritis decreased rates of pain and disability by 47% -older patients reduced progression to dementia by 50% - high risk of diabetes by 58% - post menopausal women by 41% - anxiety 40% - Depression 40-47%
Case control studies
- often referred to as retrospective -participants are selected on the basis of the presence or absence of the disease or outcome in question - you then have one group of people (case subjects) with the health problem, and one without (controls) -these groups are then compared to determine the presence of specific exposures or risk factors
five criteria that must be met to establish a cause and effect relationship
- strength of association -consistence -temporality -plausibility -biological gradient
disadvantages of cohort studies
- they are costly in time and resources - if the disease is rare you ned a large number of subjects - subjects can be lost due to follow up (because you are following forward in time)
disadvantages of case control studies
- they aren't suitable for studying rare exposures - subject to bias - they don't allow you to directly measure the incidence of disease - may create uncertainty about the temporal relationship between exposure and disease
Case control advantages
- you can examine multiple exposures for a single outcome - they are well suited for studying rare diseases and those with long latency periods - they require fewer case subjects - generally quicker and less expensive - well suited for the conditions of an outbreak investigation
psychological benefits of exercise in four broad areas
-reduction of anxiety and depression -enhancement of mood - improvement in self concept -improvement in quality of life
runners high includes
-sense of mental alertness and awareness - a feeling of liberation - a lift in the legs - suppressed pain or discomfort - and the sense of ease, perfect rythm and exhilaration
in the study regarding walking to work in japan 1990s
11-20 minutes walk - reduction in rates of high blood pressure 12%, over 21 min walk 29%
how many steps a day does the average amish man and woman walk
18000 15000
Both men and women who reported increased levels of physical activity and fitness were found to have reductions in relative risk of death by about
20%-35%
what are prevalence rates of anxiety and depression
25% for anxiety, 20% for depression
mental health problems account for what percent of total days of hospitalizations and what percent of medical costs?
30%; 10%
in patient with arthritis ___ reduced their pain by what %?
47
Physically inactive middle-aged women (engaging in less than 1 hour of exercise per week) experienced a ___ increase in all-cause mortality,
52%
How many steps a day does the average American man and woman walk
7200 5200
How many steps a day does the average canadian man and woman walk
9500 8400
what are the most common disorders in the US? effecting what percent respectively?
Anxiety disorders 17% and depression 11%
There appears to be a between the volume of physical activity and health status, such that the most physically active people are at the lowest risk
Graded linear relation
several characteristics of agents
Infectivity - the capacity to cause infection in a susceptible host pathogenicity - the capacity to cause disease in a host virulence - the severity of disease that the agent causes in the host
Both aerobic and resistance types of exercise have been shown to be associated with
a decreased risk of type 2 diabetes.
cluster defined
a group of cases in a specific time and place that may or may not be greater than the expected rate
endemic
a high background rate of disease
mood defined
a host of transient, fluctuating affective states that can be positive or negative
hardiness
a personality style that enables a person to withstand or cope with stressful situations.
Physical Fitness refers to
a physiologic state of well-being that allows one to meet the demands of daily living or that pro- vides the basis for sport performance, or both
depending on which is most effective, research may be focused on
a specific agent (e.g. guinea worm), host (immunization) or environment (sanitation improvements for salmonella)
field investigations are
action orient with the main goal being to solve a pressing public health problem
agent host and environment alone are not sufficient to cause an epidemic . what is needed
an adequate chain of transmission - a source for the agent, a portal of et, a mode of transmission, a portal of entry.
disease occurs when
an outside agent capable of causing the disease meets a host that is vulnerable to the agent in an environment that allows the agent and host to interaction
analytical epidemiology
attempt to search for causes or factors that are associated with increased risk or probability of disease
Several systematic reviews have clearly shown the importance of engaging in regular exercise to
attenuate or reverse the disease process in patients with cardiovascular disease.
Outbreak means
basically the same thing as epidemic (to an epidemiologist) but the public sees outbreak as less serous so it is often used to avoid sensationalism
routine physical activity appears to be important in preventing loss of
bone mineral density and osteoporosis, particularly in postmenopausal women.
indirect transmission
can be airborne (carried through the air), vector borne(transmitted indirectly by a live carrier), or vehicle borne (carried by inanimate objects).
mode of transmission
carrying it to the host
what are the three components of mood regulating?
changing a bad mood, raising one;s energy level, reducing tension.
Epidemiologists use several types of studies.. such as
classified as: experimental (have control over circumstances) or observational (they do not)
Descriptive observational studies
collects info to characterize or summarize a health issue
direct transmission
contact with soil or plants as well as contact between people
cross sectional study
defines the population to be studied and then collects info from members of the group about their disease and exposure status. - basically the same as a survey - taking a "snapshot" of the pop. - good for examining relationships between a variable and disease but NOT for determining cause and effect
observational studies can be classified into
descriptive (collects info to characterize or summarize a health issue) and analytical studies (relies on comparisons between groups to determine the role of various risk factors in causing the problem.)
which is the most basic of the types of epidemiology?
descriptive epidemiology
psychological explanations why exercise may have a positive effect on wellbeing
enhanced feeling of control - feeling of competency and self-efficacy -positive social interaction - improved self concept and self esteem - opportunities for fun and enjoyment
many researchers etc. have observed what mental benefits of physical activity
enhances feelings of well being in particular by reducing anxiety and depression and increasing vigor
Field or Applied Epidemiology
epidemiological data steers public health decision making and aids in developing and evaluating interventions to control and prevent health problems
basic way to explain an epidemiologists job
epidemiologists count cases of disease or injury, define the affected pop., and then compute rates of disease or injury in that pop., then they compare them and make inferences regarding the pattern of disease to determine whether a problem exists.
define the runners high
euphoric sensation experienced during running, usually unexpected, in which the runner feels a heightened sense of well being, an enhanced appreciation of nature, and a transcendence of time and space
pathway into the host - or portal of entry
gives the agent access to tissue where it can multiply or act
acute effects refer to
immediate and possibly, temporary effects arising from a single bout of exercise
exercise for the most part is linked to a variety of indexes that all relate to quality of life
increased levels of self esteem and self concept - increased feelings of enjoyment -decreased feelings of physiological and psychological stress -increased feelings of self-confidence -elevated mood states -decreased levels of anxiety and depression
Modest enhancements in physical fitness in previously sedentary people have been associated with
large improvements in health status.
australian study those who spend 6 hours a day of tv lives _____
less than 5 years
chronic effects of exercise
long term effects ; typically lasts about 2-4 months with 2-4 sessions of exercise per month
what was the strongest predictor of death in the 23 1/2 hours
low fitness
what is the dose of exercise?
more activity is better however, rate of return goes down 150 minutes/week
is high intensity aerobic activity the only activity that will produce positive benefits?
no, activities such as weight or strength training, yoga and other non-aerobic exercises have produced positive effects on well being
can we conclusively state that exercise has an effect on anxiety and depression?
no, most studies have been correlation, we cannot conclusively state that it was exercise that caused or produced the change in mood state; Rather it appears to be ASSOCIATED with positive changes in mood states and reductions in anxiety and depression
consistency means
observation of the association must be repeatable in different populations at different times
source for the agent
often the place where the agent originates where it lives, grows and multiples, but this isnt always the case.
what is the prevalence of depression
one in four americans; and increasing
physical activity is positively related to
positive mood general well being relatively infrequent symptoms of anxiety and depression
what are the conditions that facilitate a runners high
presence of few distractions and cool, calm weather with low humidity, long distances (6 or more miles0 and at least 30 minutes of running at a comfortable pace
What has been reported as one of the primary prevention types for type 2 diabetes
regular physical activity exercise interventions
Analytical observational studies
relies on comparisons between groups to determine the role of various risk factors in causing the problem
both physical activity and fitness are strong predictors of
risk of death
exercise and physcial activity can be related to a participants
self concept, self esteem, and self efficacy
Routine physical activity, whether as part of a job or as a leisure activity, is associated with reductions in the incidence of
specific cancers, in particular colon and breast cancer Physically active men and women exhibited a 30%-40% reduction in the relative risk of colon cancer, and physically active women a 20%-30% reduction in the relative risk of breast cancer compared with their inactive counterparts.
what are the findings regarding physical activity and cognitive functioning?
still inconsistent, but had a modest positive relationship
descriptive epidemiology
study the distribution of frequencies and patterns of health events within a group in a population
host can be classified as
susceptible, immune or infected
temporality means
the cause must precede the effect
Health related physical fitness involves
the components of physical fitness related to health status, including cardiovascular fitness, musculoskeletal fitness, body composition and metabolism
environment is
the conditions or influences that are not part of either the agent or the host , but that influence their interaction.
agent defined
the entity necessary to cause disease in a susceptible host can be biological (bacteria, parasite), or physical force ( motor vehicle crash, chemical)
plausibility means
the explanation must make sense biologically
preliminary evidence indicates that regular physical activity is an effective secondary preventive strategy for
the maintenance of bone health and the fight against osteoporosis.
epidemic defined
the occurrence of more cases of disease than would normally be expected in a specific place or group of people over a given period of time
portal of exit
the pathway by which the agent can leave the source - usually realted to the place where the agent is localized.
host defined
the person, or the organism that is susceptible to the effect of an agent
field epidemiology
the practice or application of epidemiology to control and prevent health problems
what is the primary instrument measuring changes in mood in sport and exercise?
the profile of mood states other popular ones: positive affect-negative affect scale activation-deactivation adjective checklist exercise induced feeling inventory
strength of association means
the relationship must be clear
An increase in physical fitness will reduce
the risk of premature death, and a decrease in physical fitness will increase the risk
regular physical activity is clearly effective in
the secondary prevention of cardiovascular disease and is effective in attenuating the risk of premature death among men and women.
define epidemiology
the study of the distribution and determinants of health-related states in specified populations, and the application of this study to control health problems
biological gradient means
there must be a dose-response relationship
exercise therapy should not be prescribed to
those who are obese, those with severe heart disease, those with high blood pressure that cannot be controlled by medication.
pandemic
very widespread, often global disease
What type of exercise appears to have the greatest effects on bone mineral density
weight bearing exercise, especially resistance exercise. there is compelling evidence that routine physical activity, especially weight-bearing and impact exercise, prevents bone loss associated with aging
Cohort study
you select the study population according to their exposure, then determine the outcomes and compare them on the basis of exposure. - often refered to as prosepctive studies -follow a pop. forward in time - use to investigate outbreaks in SMALL, WELL DEFINED POP.