Reading
n
Westerterp, Assessment of physical
activity: a critical appraisal.
Purpose
n
Define key terminology and understand the relationship between physical activity
and health.
n
Review recommendations for physical activity to maintain health and prevent
disease.
n
Evaluate different methods used to assess physical activity in various
populations.
Physical activity: voluntary movement produced
by muscular contraction and requiring energy expenditure
Physical activity and health
Morbidity: risk of chronic disease (heart disease, diabetes,
hypertension, stroke, cancer)
Mortality: risk of premature death
Recommendations for maintaining health and preventing disease
Introduction
What is physical activity? A common description is “any voluntary movement produced by muscular contraction and requiring energy expenditure.”
Physical activity must have two components: movement and behavior.
Movement is the muscular contraction and the behavior component is the voluntary action.
Most physical activity instruments only assess one component or measure
the outcome variable energy expenditure.
Relationship Between Physical activity and Health
Research by Paffenbarger, Blair and others started linking physical activity to all-cause mortality (risk of pre-mature death), first in men and then later in women.
Paffenbarger’s College alumni Health Study began in 1960 and investigated the exercise habits of over 50,000 Harvard University and University of Pennsylvania alumni.
The results of this study showed that the more physically active individuals had a lower risk of coronary heart disease and live longer.
Blair studied a population of patients receiving a preventive medical examination at the Cooper Clinic in Dallas.
The patients received a full physical and physical fitness was measured by a maximal treadmill exercise test.
After approximately 8 years of follow up, results indicated age-adjusted all-cause mortality rates declined across physical fitness levels.
Additionally, lower mortality rates were seen in higher fitness groups for cardiovascular disease and cancer.
Many studies followed to
confirm these results in different populations and age ranges.
The study of physical activity stepped into the spotlight once the connection was made to mortality and morbidity (risk of chronic disease) and many national organizations have published recommendations for the amount and type of physical activity necessary to improve health.
The recommendations change slightly over the years as the relationship between physical activity and health is better understood.
The current guidelines from the U.S. Department of Health and Human Services (HHS) were met with support from the American College of Sports Medicine (ACSM) and the American Heart Association (AHA) and can be accessed here – physical activity guidelines.
It is important to note, that by following
these guidelines an individual may improve their health outcomes or decrease
their mortality risk but not necessarily improve performance.
