Chapter 03
Measurement and Surveillance of
Physical Activity and Fitness
• Behavioral Epidemiology-The observation and study of
behaviors that lead to premature death and of the distribution of
these behaviors.
IMPORTANT QUESTIONS:
• What are the relationships between behavior and disease ?
• What are the determinants and distribution of the behavior
in the population ?
• If the behavior can be linked to the disease, then how can
the behavior be altered to prevent, or contain, or cure
disease? Thus, behavioral epidemiology the focus is to
understand the behaviors that increase or decrease the risk
of developing disease.
Measurement and Surveillance of Physical
Activity and Fitness
• Behavioral Epidemiology is used to observe, study, and change
unhealthy behaviors. Physical inactivity has been observed,
studied, and recommendations have been made to change the
unhealthy behavior. Because physical (in) activity is a behavior,
it is a focus of Behavioral Epidemiology.
• Physical Activity – “Any bodily movement produced by skeletal
muscle that results in energy expenditure”. Physical activity is the
most variable component of daily energy expenditure, thus
activity becomes a behavioral choice for increasing or decreasing
daily energy expenditure.
• Physical Activity Epidemiology
– Compares levels of physical activity and disease or injury risk
Measurement and Surveillance of Physical
Activity and Fitness
• Measures of Physical Activity (energy expenditure)
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Calorimetry
Doubly Labeled Water
Heart Rate Monitors
Motion Sensors
Physical Activity Questionnaires
Measurement and Surveillance of Physical
Activity and Fitness
• Measures of Physical Activity
• Calorimetry
– Calories (unit of energy) can be measured by using either
direct or indirect colorimetry
– Direct Calorimetry involves the measure of heat production
of an individual in a sealed, insulated chamber.
– Indirect Calorimetry involves estimating energy expenditure
from oxygen consumption and carbon dioxide production.
• Caloric equivalents = 5 kcal / 1 L O2
Measurement and Surveillance of Physical
Activity and Fitness
• Measures of Physical Activity
• Doubly Labeled Water (DLW) – Water that has isotopes of hydrogen
and oxygen that diffuse into the fluid volume of the body. When the water is
drunk, the two isotopes rapidly distribute in the body and start to be
eliminated from the body.
– The hydrogen isotope measures water flux
– The oxygen isotope measures the water and carbon dioxide
flux
– The difference between the two is carbon dioxide flux
– Recall that measuring CO2 is indirect colorimetry
– Allows for energy expenditure to be measured outside of the
laboratory setting
– Expensive cost of DLW and analysis equipment make its use
prohibitive for most epidemiology studies with large numbers
of subjects
Measurement and Surveillance of Physical
Activity and Fitness
• Measures of Physical Activity
Heart Rate Monitors – Monitors that are strapped to the chest
wall and store heart rate data that can be downloaded into
computer programs for analysis. Monitors also display real
time heart rates on a digital watch.
Monitors are used to measure indirect colorimetry because of
the assumed linear association of heart rate to oxygen
consumption. This association is often calculated via
regression analysis, and there is no “perfect association” for
any level of activity, only a predicted association. Thus
validity of this association is questionable at various activity
levels.
Measurement and Surveillance of Physical
Activity and Fitness
• Measures of Physical Activity
• Motion sensors
• Motion sensors such as pedometers (counters) have a history of
poor validity and reliability of measure. Even the pedometers
studied with high validity showed problems with interunit
reliability.
• Accelerometers determine vertical displacement, and provide a
measure of frequency and intensity of movement.
Accelerometric measures have a higher correlation with energy
expenditure than pedometers when examining walking and
running activities. Mass use of accelerometers is still cost
prohibitive in large epidemiology studies.
Measurement and Surveillance of Physical
Activity and Fitness
• Measures of Physical Activity
• Physical Activity Questionnaires
– Physical activity questionnaires are the most practical
and often used method of assessing physical activity
in epidemiologic studies. This format allows for the
collection of physical activity information from large
numbers of people in a time and cost efficient
manner.
Measurement and Surveillance of Physical
Activity and Fitness
• Physical Activity Questionnaires
– Commonly Used Questionnaires
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Minnesota Leisure Time Physical Activity Questionnaire
Harvard Alumni Physical Activity Survey
Stanford Seven-Day Physical Activity Recall
International Physical Activity Questionnaire (IPAQ)
Global Physical Activity Questionnaire (GPAQ)
Community Health Activities Model Program For Seniors
(CHAMPS)
• It is generally thought that individuals tend to overestimate
participation in vigorous activity and underestimate
participation in light-to-moderate activities.
• Additional works needs to be done to enhance the recall of
physical activity intensity on self-report measures.
• Physical Fitness
– Can be measured as an out come of physical activity
– Can be measured as a moderator on morbidity and
mortality
– Physical fitness for purposes of health, is best
defined by the specific components that relate to
improved health or reduced disease. The
components of Health-Related Fitness are on Table
3.2, p.49, text. The major categories are: (see next slide)
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Morphological
Muscular
Motor
Cardiorespiratory
Metabolic
Measurement and Surveillance of Physical
Activity and Fitness
The Components of Health
Related Fitness
Measurement and Surveillance of Physical
Activity and Fitness
• Physical Fitness – Morphological Component
– Variables
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Body mass for height
Body composition
Subcutaneous fat distribution
Abdominal fat distribution
Bone Density
Flexibility
Measurement and Surveillance of Physical
Activity and Fitness
• Physical Fitness – Morphological Component
– Measuring Body Fatness
• The relationship of body mass to fatness is most
commonly expressed as Quetelet’s Body Mass Index
(BMI)
– BMI = Body mass (kg) / Height ( m) 2 .
– High BMI ( >25, men ; >30 women) is a risk factor for all-cause
mortality and increases the risk for hypertension, high
triglycerides, high cholesterol, impaired glucose tolerance, and
high insulin levels.
– BMI is a not a valid measure in athletic (large fat-free mass),
pregnant, or frail elderly persons
Measurement and Surveillance of Physical
Activity and Fitness
• Measuring Body Fatness
– Fat Patterning
• Android Pattern Obesity – Concentration of body fat
predominately along the trunk (apple shape)
• Gynoid Pattern Obesity – Concentration of body fat
predominately along the hips ( pear Shape)
• Android obesity is more prevalent in men, gynoid in
women.
• Circumference measurements are taken at the level of the
hip ( gluteus) and the waist (umbilicus), and waist-to –hip
ratios are derived.
• Waist-to- hip rations ≤ 0.85 in women and ≤ 0.95 in men
increase risk of metabolic disorders
Measurement and Surveillance of Physical
Activity and Fitness
– Bone Mass
• Bone mass is measured via Dual X-ray absorptiometry
(DXA)
• Osteoporosis results from accelerated bone mass loss
• Risk Factors
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Small Frame Caucasian Women (inherited susceptibility)
Amenorrhea
Low dietary calcium
Post menopause
Physical Inactivity
** Negative Risk = Increased lean mass
Measurement and Surveillance of Physical
Activity and Fitness
– Flexibility
• Defined as the range of motion of a specific joint during
both passive and dynamic movement
• Flexibility is joint specific
• The loss or gain if flexibility is very specific to each joint
• As a measure of physical fitness, flexibility is usually
distinguished from the laxity of a joint, which is a measure
of joint instability governed largely by the tightness of
ligaments.
Measurement and Surveillance of Physical
Activity and Fitness
• Muscular Component
– Muscular Strength /Muscular Endurance
• Muscle Mass typically decreases as a function of aging
• Increase in fat mass often accompanies the decrease in
muscle mass
• Loss of muscular fitness decreases mobility, strength, and
endurance needed for Activities of Daily Living (ADL)
• Maintaining muscular fitness in the trunk mayu reduce the
risk for low back pain
Measurement and Surveillance of Physical
Activity and Fitness
• Motor Component
– Motor Fitness is determined by speed of movement,
agility, balance, and coordination
– Poor coordination and balance increases the risk of
falls and fractures aged adults
– Low motor fitness in childhood may have a longlasting impact, contributing indirectly to sedentary
living among adults who did not develop the
psychomotor skills needed for many leisure physical
activities.
Measurement and Surveillance of Physical
Activity and Fitness
• Cardiorespiratory Component
– Considered a major component of physical fitness in
the prevention of CHD.
– Subcomponents include:
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Maximal Aerobic Capacity
Submaximal Exercise Capacity
Cardiac Function
Pulmonary Function
Blood Pressure
Measurement and Surveillance of Physical
Activity and Fitness
Subcomponents :
• Maximal Aerobic Capacity
– Maximal oxygen uptake measured in both absolute and relative
terms. Absolute measures = ( L/min or ml/min ); Relative (
ml/kg-1/min-1
– Measured during a maximal aerobic test when fatigue occurs
• Submaximal Exercise Capacity
– The ability to sustain an intensity of power output for a
prolonged period of time that is below the maximum aerobic
capacity
• Cardiac Function
– Assessed by determining heart functions
– Heart rate, ejection fraction, myocardial shortening rate, cardiac
output ( stroke volume times heart rate)
Measurement and Surveillance of Physical
Activity and Fitness
Subcomponents include:
• Pulmonary Function
– Lung Functions have both static and dynamic volumes (see
details in text)
– These volumes can be affected by Chronic Obstructive
Pulmonary Diseases
• Blood Pressure
– High blood pressure can occur in systolic and/or diastolic
pressures
– High blood pressure is considered > 140/90 mmHg
– Chronic high blood pressure increases the risk of stroke, heart
attack, sudden cardiac death, aneurisms, and other organ failures
Measurement and Surveillance of Physical
Activity and Fitness
• Metabolic Component
– Metabolic fitness is the newest component of fitness
recognized by exercise physiologists and
epidemiologists who study health. It appears
especially useful for understanding the potential
health benefits of physical activity for preventing
diabetes and atherosclerosis, the disease process
leading to CHD and stroke.
– Subcomponents include:
• Glucose Tolerance
• Blood Lipid and Cholesterol Profiles
• Lipid Oxidation
Measurement and Surveillance of Physical
Activity and Fitness
– Subcomponents include:
• Glucose Tolerance
– Regular exercise can be used to treat glucose intolerance in Type
II diabetics.
– Effects of exercise include normalizing insulin and glucagon
production by the liver, increasing insulin sensitivity by the
exercising muscle, thus enhancing glucose uptake.
• Blood Lipid and Cholesterol Profiles
– Exercise decreases total blood cholesterol, increases HDLCholesterol, and decreases blood triglycerides.
• Lipid Oxidation
– High lipid oxidation alters cholesterol metabolism and reduces
body fat to reduce risk of cardiovascular disease. Thus, chronic
aerobic exercise spares glucose stores and uses more fat
oxidation for fuel.
• Exercise Training
– Exercise training can be described by
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F requency – How often ?
I ntensity – How hard?
T ime – How long ?
T ype – Mode of exercise
– Fitness Guidelines ( see Table 3.3, p. 53, text, and
next slide)
Measurement and Surveillance of Physical
Activity and Fitness
Table 3.3 ACSM 1998 and 2008 Federal
Physical Activity Guidelines for Americans
• F.I.T.T.
– Frequency
• 3-5 times /week for improving fitness, most days of the
week to improve health (improving fitness supposes an
improvement in health)
– Intensity
• 50-85% VO2 max ( and Heart Rate Reserve) for
cardiorespiratory fitness – Note new guidelines focus on
METS
• 40% good start point for obese and sedentary
• 50-85% Rep Max with 8-15 reps, depending on age and
desired muscular fitness outcome (muscle strength vs.
endurance). Focus should be on major muscle groups
• With flexibility exercises, one should “feel” the stretch,
but it should not be painful
Measurement and Surveillance of Physical
Activity and Fitness
– Time
• 20-60 minutes(≥75 min/wk), longer duration and lower
intensity is effective on body fat loss
• Resistance exercises for each of the major muscle groups
2 or 3 days/week
– Type
• Activities that involve:
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Large muscle groups
Repetitive activity
Continuous activity
Exercises involving balance, agility, and coordination; and
flexibility exercises for each of the major muscle–tendon groups
(a total of 60 s /exercise) on ≥2days/week
Measurement and Surveillance of Physical
Activity and Fitness
Exercise Training
• Because body systems respond in very specific
ways to the challenges imposed by different
modes of exercise, a well-balanced exercise
training program includes several modes. Certain
types of physical activity that affect specific
components of physical fitness might be
especially effective in reducing the risk of
specific diseases (table 3.4) – next slide
Measurement and Surveillance of Physical
Activity and Fitness
Table 3.4 - Dimensions of Physical Activity With Proposed
Mechanism of Effect, Diseases or Conditions Affected, and
Potential Surveillance Definitions
Measurement and Surveillance of Physical
Activity and Fitness
• Dose Response of Physical Activity and Health
– Recall that establishing a dose response is one of the
criteria for establishing causation
• Findings of Fact
– An inverse relationship and a generally linear
relationship exists between physical activity and rates
of all cause mortality and morbidity attributable to
CVD and CHD incidence and mortality, and to
Type II diabetes.
Measurement and Surveillance of Physical
Activity and Fitness
Table 3.5 Summary of Evidence for Dose–Response
Effects of Physical Activity on Adult Health
Measurement and Surveillance of Physical
Activity and Fitness
• Findings of Fact, continued…
– Other health outcomes may have a doseresponse effect, however:
• 1) in some areas not enough studies examined the
dose-response question
• 2) measures of physical activity have been
imprecise
• 3) some responses to physical activity have been
to small to study the dose influence
• 4) other confounding factors were not controlled
Measurement and Surveillance of Physical
Activity and Fitness
• Surveys and Surveillance of Physical Activity
– Surveys are used to determine the prevalence of
physical activity in the population
– Trends in physical activity may be established by
repeating the survey over the course of years. This
action is called surveillance. Thus surveillance is
necessary to measure secular trends in physical
activity.
Measurement and Surveillance of Physical
Activity and Fitness
Table 3.7 Summary of U.S. Physical Activity
Surveillance Data Sources
Measurement and Surveillance of Physical
Activity and Fitness
• Physical Activity Surveillance in the United
States
• Geographic Variation
– Most active region = Rocky Mountain and
Northwest; Least = Southeast
– States : Washington - 49% active; Washington D.C.
– 19 % active (See Figure 3.11, text, see next slides)
Measurement and Surveillance of Physical
Activity and Fitness
Figure 3.11 Who’s physically active? percentages of adults in each state, the District of
Columbia, and three U.S. territories meeting the healthy people 2010 recommendation for either regular
vigorous physical activity (≥20 min per day on three or more days per week) or regular moderate activity
(≥30 min per day on five or more days per week) in (a) 2005 and (b) 2007. Based on BRFSS 2008.
Measurement and Surveillance of Physical
Activity and Fitness
Figure 3.11 Who’s physically active? percentages of adults in each state, the District of
Columbia, and three U.S. territories meeting the healthy people 2010 recommendation for either regular
vigorous physical activity (≥20 min per day on three or more days per week) or regular moderate activity
(≥30 min per day on five or more days per week) in (a) 2005 and (b) 2007. Based on BRFSS 2008.
Measurement and Surveillance of Physical
Activity and Fitness
• Physical Activity Surveillance in the United
States
• Population Subgroups
– (see Figures 3.13-3.14, next slides)
• White males are the most active (girls become less active
during adolescence)
• Physical activity decreases with age
• Physical activity increases with education level
– In Class Discussion: “Physical Activity, Fitness, and
Aging” (p. 68-69)
Measurement and Surveillance of Physical
Activity and Fitness
Figure 3.13
Regular physical activity in the
United States according to (a)
gender and age, (b)
race/ethnicity, and (c)
education level. the dashed line
indicates the national goal of
50%.
Data from centers for Disease Control and
Prevention, Health, United States, 2008.
available:
www.cdc.gov/nchs/hus/updatedtables.htm.
Measurement and Surveillance of Physical
Activity and Fitness
Figure 3.14
Physical inactivity in the United
States according to (a) gender and
age, (b) race/ethnicity, and (c)
education level. the dashed line
indicates the national goal of 20%.
Data from centers for Disease control and
prevention, health, United States, 2008.
available:
www.cdc.gov/nchs/hus/updatedtables.htm
Measurement and Surveillance of Physical
Activity and Fitness
End of Presentation
Measurement and Surveillance of Physical
Activity and Fitness