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.