Epidemiology and Physical Activity

Epidemiology

study of the relation among various factors that determine the frequency and distribution of diseases in a population

Early work focused on…

acute illness

• 1700’s: Scurvy

• 1800’s Cholera

Incidence

number of NEW CASES with a given outcome at a specified point in time

• never larger than prevalence

Prevalence

number of EXISTING CASES with a given outcome at a point in time

Mortality

number of DEATHS in a population

Morbidity

number of CASES if disease

Pathophysiology

SYMPTOMS and physiological processes associated with the disorder (what’s going on inside)

Etiology

known or suspected CAUSE of disorder

Classification

organization of disorder phases

• by symptom presence or severity, progression, age, functional abilities

Exercise response

ACUTE measurements

• often made on 1st or 2nd visit to clinic/ gym

• measures 1 thing at a time

• not specific to a certain device

Exercise training

LONG TERM changes in measurements

• can be made weeks, months, or years after first visit to clinic/ gym

Exercise testing

measuring the body’s REACTION to increases in exercise challenge

• often performed on treadmill or ergometer

• very specific protocol

• measures as many things as possible with 1 test (HR, BP, VO2, ECG, etc.)

Exercise programming

a specific plan of exercise activities that form the basis of an exercise prescription

3 pillars of exercise programming

aerobic, resistance (strength), flexibility

Measures of Physical Activity

• Objective measurement

• Self-report questionnaries

• Fitness

Objective measurement

Assessed by:

• HR monitors

• Accelerometers

• Pedometers

• Diaries/ logs

Good VALIDITY (truth) and RELIABILITY (consistent)

Drawbacks:

• Participants forgetting to wear devices

• Not practical for large populations

Self-report questionnaires

Used for large population studies

• face to face & phone interviews

• self administration

Many have been validated and are accurate (low reliability with children)

Fitness

• CV fitness is quantified by VO2 max

• Fitness status and change in ftiness status have been shown to be associated with all-cause mortality and other outcomes, including CVD

• ↑ VO2 max= ↑ life span (and vice versa)

• ↑ fitness consistency= ↑ life span

All-cause mortality vs weekly energy expenditure

Target energy expenditure: 3000-3499 kcal/wk

What causes autism?

POOP AND MICROPLASTICS

Health benefits associated with physical activity (children and adolescents)

• ↑ bone health

• ↑ weight status

• ↑ CV and muscular fitness

• ↑ cardiometabolic health (resistance training is better)

• ↑ cognition

• ↓ risk of depression (aerobic is better)

Health benefits associated with physical activity (adults and older adults) part 1

• ↓ all-cause mortality

• ↓ CV disease mortality

• ↓ risk of CV and CBV (stroke) disease

• ↓ hypertension

• ↓ type 2 diabetes

• ↓ adverse blood lipids (cholesterol)

• ↓ cancers of bladder, breast colon, etc.

• ↓ dementia (Alzheimer’s)

Health benefits associated with physical activity (adults and older adults) part 2

• ↑ immune system function

  • diet helps

• ↓ inflammation

  • internal! (i.e. organs, joints— can spread)

**gut health is important to overall health

Literature on Physical activity on health

• Earliest literature focused on the importance of exercise

• Early to mid-1900s: literature focused on the threat of infectious disease

• Last 50 to 75 years:

  • Development of antibiotics and new treatments

  • Attention has shifted to study of chronic diseases

London study

Study observing bus workers (ticket taker vs driver) that was the first association between those who are active while working and better physical health

Population studies

• Framingham study

• The China study

• 1987: first study on physical activity and CVD

Framingham study

• 1948 to present

• study started with observing ~5,000 people and getting medical workups every so often

• now onto 4th generation of those original participants and seeing connection between physical activity and disease

The China Study

• Landmark nutritional study

• very controversial

• conclusion: lifespan is increases when you don’t consume animal products or cholesterol— basically follow a plant based diet

1987

• first definitive study of published studies on physical activity and CVD

• First to conclude that increased physical activity leads to a decreased risk of CVD

Leisure World Cohort Study

• Focused on elderly

• Purpose: what can you do to love longer and increase quality of life

• Observational study

Leisure World Cohort Study: what contributes to longevity?

• BMI

• Physical activity

• Caffeine (100 mg per day)

• Alcohol (1 drink for women and 2 for men per day)

Leisure World Cohort Study: BMI and All-Cause Mortality

BMI at 21: Normal BMI has least risk of all-cause mortality

BMI at Baseline (~74): Overweight BMI has least risk of all-cause mortality

• Most recommended for increased lifespan and quality of life for elderly

Leisure World Cohort Study: Physical Activity and All- Cause

Mortality

Swimming for 1-1.75 hrs/day= lowest risk of all-cause mortality

The 90+ Study: What Contributes to Dementia?

Hypertension- has a huge impact (idrk why lol)