Chapter 3 Measurement and Surveillance of Physical Activity and Fitness

Behavioral epidemiology is the observation and study of behaviors, including physical inactivity, which leads to disease or early death and of the distribution of these behaviors. This contain 2 main features: (1) the study of relationships of behavior and disease (2) the study of the behavior, its distribution in a population and its determinants. In modern behavioral epidemiology, the focus shifts to understanding behaviors that increase or decrease the risk of people developing the disease (hand washing, sharing needles). Important for understanding and preventing chronic diseases that develop over a period of years because of people’s habits. Pandemic: an epidemic that spreads widely across a region or the world. About half the mortality from the top 10 leading causes of death in the U.S.A. can be traced directly or indirectly to behavior.

 What is physical activity?  3 parts of energy expenditure: (1) Metabolism (2) Physical activity (3) Thermic effect of food  Measures of Physical Activity: Used to be done by occupational classification—ignoring leisure- time physical activity.  Then both measured by the Tecumseh Community Health Survey—no there are about 50 physical activity questionnaires.---No gold standard to compare questionnaire results though.  Imperfect measures of calorimetry: by using variables influenced by physical activity (BP, fat, blood lipids, aerobic power, muscular strength & endurance).  Direct (sealed insulated chamber) vs. indirect calorimetry (doubly labeled water, heart rate monitors, Motion sensors—accelerometers, pedometers, multiplane accelerometers, diaries, slef- reports)

Physical Activity Questionnaires 1.Minnesota Leisure Time Physical Activity Questionnaire 2.Harvard Alumni/Paffenbarger Physical Activity Survey 3.Stanford Seven-Day Physical Activity Recall Interview 4.International Physical Activity Questionnaire 5.Global Physical Activity Questionnaire 6.3-Day Physical Activity Recall (3-D PAR) 7.CHAMPS Physical Activity Questionnaire  Self-Reports of physical activity are the most feasible method for measuring physical activity in national surveys and surveillance systems. Objective measures, such as motion sensors, heart rate monitors, and doubly labeled water can estimate different components of physical activity and are commonly used to validate self-report measures.

What is Physical Fitness?  Physical fitness is both genetic and influenced by what you do.  Health-Related Physical Fitness Components: (Table 3.2, page 49).  Performance-Related Fitness.  Morphological: Fatness—BMI, overweight, overfat, % body fat, distribution of fat; Bone Mass; Flexibility;  Cardiorespiratory—max and submax aerobic capacity, cardiac function—HR, ejection fraction, stroke volume, Q; Blood Pressure  Metabolic Component: aids in preventing diabetes and atherosclerosis; Glucose Tolerance; Blood Lipid & Cholesterol Profiles; Lipid Oxidation  Muscular Component--Muscular—strength, endurance, power.  Motor: Psychomotor—childhood skills, etc.

Exercise Training  F I T T  ACSM guidelines: (p-53).  Frequency: cardio—3 to 5 days per week  Intensity—(p-53 & 54).  Time or Duration: cardio—20 to 60 minutes (ACSM). J-Curve & Dose-Response..  Type or Mode: (p-54).  Dose-Response: Establishing dose-response is one of Mill’s canons for determining the causality of a health risk factor, but it is also important for public health policy recommendations about the types and amounts of physical activity that are healthful.

Dose-response Evidence  P-55  National Runner’s Health Study: Cross-Sectional study about a linear dose-response relationship between activity and health outcomes.  Current Scientific Consensus: An inverse, and generally linear, relationship exists between physical activity and rates of all-cause mortality, CVD mortality, and the incidence of type 2 diabetes.  Consensus was not reached bout dose-response for other health outcomes evaluated…  P-58, Table 3.5  Surveys and Surveillance of Physical Activity, p-57 through 62.

 Physical activity in the U.S.A.  Geographic variation  Population subgroups  Secular changes in culture can strongly influence the prevalence of physical activity. Examples are increased TV viewing and computer use among youths and a decrease in daily physical education during the past decade.  Physical activity, fitness and aging.