Assignment 2 Rephrase all the wording. 1. What was the unique way Dr. Morris combined the areas of physical activity and public health? Dr. Morris conduct

Assignment 2

Rephrase all the wording. 

1. What was the unique way Dr. Morris combined the areas of physical activity and
public health?

Dr. Morris conducted a study on workers (large group of men who worked all day
moving people around the city of London) employed by the London transport system.
Dr. Morris assessed their physical activity rates and then related it to the risk of getting a
heart attack. Dr. Morris studied the bus drivers who were inactive all day long and the
conductors who were walking up and down the stairs of the buses taking tickets from
riders all day. (Morris et al. 1953) Physically active conductors had significantly lower
rates of coronary heart disease than the drivers. If conductors did develop the
disease, it was less severe and occurred at later ages. Dr. Morris promoted
physical activity and health, not just exercise for performance.

Dr. Morris also found that postmen delivering the mail on foot had similarly lower
CHD rates than sedentary postal clerks and telephonists. Analysing national
death rates in an early test of their hypothesis, the Morris team found gradient
levels of CHD with occupations of intermediate physical activity.

Dr. Morris chose middle aged civil servants free of clinical CHD who held
sedentary desk jobs and traced them over time for CHD occurrence and death.
Contrary to expectation, no benefit in lower heart attack incidence was found
from high totals of leisure time physical activity. Instead, men engaging in
vigorous exercise (for example, running at about 6 mph) did manifest less than
half the disease of their fellow workers, who were comparable in health status
and health habits. (Paffenbarger, R. S., 2000)

2. What is the exercise/heart hypothesis?

Exercise/ heart hypothesis protects against coronary heart disease. People who
exercised more frequently had healthier, better functioning circulatory systems than
those who did not exercise. This physiological benefit resulted in a lower risk of death
from heart disease among those who were more active. Nowaday, in primary
prevention, regular physical activity decreases the incidence of cardiovascular disease.
Exercise has an effect on cardiovascular improvement in lean and overweight
normoglycemic subjects. In a 1-year study in non-obese individuals, without dietary
intervention, a 16-20% increase in energy expenditure (any form of exercise) resulted in
a 22.3% reduction in body fat mass, LDL cholesterol , total cholesterol/high-density
lipoprotein lowering ratio, and C-reactive protein concentration, all risk factors
associated with CVD.(Fontana L, 2007)

Exercise induces adaptations in several cell types and tissues throughout the body.
Exercise increases mitochondrial biosynthesis in adipocytes, skeletal muscle myocytes,
and cardiomyocytes, thereby increasing aerobic respiration within these tissues. In
addition, exercise improves systemic oxygen delivery through vasodilation and
angiogenesis, preventing cardiac ischemia-reperfusion injury. In addition, exercise leads
to long-term anti-inflammatory effects that are inversely associated with increased
inflammation commonly seen in CVD and obesity. (Kasapis C, 2005)

3. What are five chronic disease conditions that might be positively influenced by
participation in regular physical activity? Discuss each.

Heart disease: Dr. Morris found that the physically active conductors had significantly
lower rates of coronary heart disease than the less active drivers. The exercise/heart
hypothesis, now more of an accepted fact than a hypothesis. People who exercised
more frequently had healthier, better functioning circulatory systems than similar people
who did not exercise. Regular physical activity also results in lower blood pressure,
healthier cholesterol levels, and better blood sugar regulation. It encourages the heart’s
arteries to dilate more readily.

Cancer: Physical activity, including both aerobic and resistance exercise, has protective
effects on cancer risk because it improves insulin sensitivity, reduces circulating insulin
levels, increases glucose intake by skeletal muscle, lowers fatty acid synthesis, and
improves immunity.

Stroke: Physical activity provides strong preventative effects on stroke recurrence. The
American Stroke Association (ASA) noted that physical activity reduces blood pressure,
improves endothelial function, reduces insulin resistance, improves lipid metabolism,
and may help reduce weight. Physical activity helps lower high blood pressure which is
an important risk factor for stroke. It can control other things that can put at risk such as
obesity, and high cholesterol.

Pulmonary disease: Physical activity especially aerobic exercise can improve the
circulation and help the body better use oxygen. Build energy levels so that people can
do more activities without becoming tired or short of breath.

Osteoporosis: Physical activity can reduce bone loss in terms of reducing fracture risk.
When people exercise regularly, the bone adapts by building more bone and becoming
denser. It also improves balance and coordination.

Diabetes mellitus: Physical activity can make the body more sensitive to insulin which
helps manage diabetes. It can also help control blood sugar levels. It can also helps
control weight.

4. What are the 2018 Physical Activity Guidelines for Americans?

For children (aged 3 to 5 years), preschool-aged children should be active throughout
the day to enhance growth and development. Children this age should be encouraged
into active play for at least 3 hours per day. For children and adolescents (aged 6 to 17
years), children and adolescents should do 1 hour or more of physical activity every
day. Most of the 1 hour or more per day should be either moderate or vigorous intensity
aerobic physical activity. As part of their daily physical activity children and adolescents
should do vigorous-intensity activity at least 3 days per week. They also should do
muscle-strengthening and bone-strengthening activity at least 3 days per week. For
adults (aged 18 to 64), adults should do 2 hours and 30 minutes per week of
moderate-intensity, or 1 hour and 15 minutes per week of vigorous-intensity aerobic
physical activity, or an equivalent combination of moderate and vigorous intensity
aerobic physical activity. Aerobic activity should be performed in episodes of at least 10
minutes, preferably spread throughout the week. Additional health benefits are provided
by increasing to 5 hours per week of moderate-intensity aerobic physical activity, or 2
hours and 30 minutes per week of vigorous-intensity physical activity, or an equivalent
combination of both. Adults should also do muscle-strengthening activities that involve
all major muscle groups performed on two or more days per week. For older adults
(aged 65 and older), they should follow the adult guidelines. If this is not possible due to
limiting chronic conditions, older adults should be as physically active as their abilities
allow. It is important for older adults to avoid inactivity. Older adults should do exercises
that maintain or improve balance if they are at risk of falling.

5. Define the following terms:

(a) total energy expenditure – TEE, also referred to as total caloric expenditure – The
combination of one’s resting metabolism (basal metabolic energy expenditure), thermic
effect of food, and physical activity energy expenditure over time, usually expressed as

(b) thermic effect of food – TEF, the amount of energy that is used to digest and
metabolize energy that is ingested (food and drink). Usually expressed as kilocalories.

(c) basal metabolic energy expenditure – BMEE, the energy expended to maintain
breathing and circulation while at rest; usually expressed as kilocalories.

(d) accelerometers – Small piezoelectric devices that estimate physical activity energy
expenditure by measuring movement. Specifically, they measure the magnitude and
direction of acceleration. They constitute an indirect measure of physical activity.

(e) pedometers – electronic monitoring devices that can be used to take the recall bias
out of physical activity assessment. They are usually most useful for measuring walking,
running or jogging, or any other type of physical activity that involves the lower body.
Some rely on a spring or a spring lever to record the movement, others use a strain
gauge, and still others use a magnetic switch.

6. What two direct observation techniques are commonly used for measurement of
physical Activity?

Sofit is a system for observing fitness instruction time and Soparc is a system for
observing play and recreation in communities. They are two examples of direct
observation techniques to assess physical activity among children and adolescents in
defined areas. Both measure, developed at San Diego State University by Dr. Thom
Mckenzie and colleagues have helped to get objective measures of physical activity in
youth. SOFIT is used to assess the amount of physical activity occurring during physical
education classes, or during any physical activity class setting (e.g. an aerobics or yoga
class). SOFIT provides important information about the quality of the physical activity
class by measuring not only the amount of physical activity the students are engaging in
during class, but also the quality of specific class activity and behaviors of the instructor.
SOPARC is used to measure physical activity and associated environmental
characteristics in park and recreational settings.

If an organization may be interested in diagnosing and improving the levels of physical
activity occurring in public recreation centers in low-income neighborhoods. SOPARC
would be an excellent tool for measuring physical activity in that project. Therefore,
direct observation techniques can be very useful in many situations.

7. What is public health surveillance, and how does it apply to physical activity
measures? what are the three sources of public health surveillance data related to
physical activity behaviors?

Public health surveillance is the continuous, systematic collection, analysis and
interpretation of health-related data (e.g. regarding agent or hazard, risk factor,
exposure, or health event) needed for the planning, implementation, and evaluation of
public health practice. Surveillance helps understand the extent of a health problem and
identify the types of people and populations that may be at higher risk of that health
problem. Physical activity is any skeletal movement that results in energy expenditure. It
is a behavior and energy expenditure in the direct result that physical activity has on
bodies. The most accurate techniques to measure physical activity are those that
involve quantifying the amount of energy expenditure that results from being physically
active. It is because noncommunicable diseases are becoming an issue, acknowledging
physical activity and its importance in decreasing disease risk helps determine the dose

and types of physical activity needed for health benefits. For example, the best
science-based guidelines state that adults should accumulate at least 150 minutes per
week of moderate-intensity physical activity or at least 75 minutes per week of
vigorous-intensity physical activity or some equivalent combination of intensities (U.S.
Department of Health and Human Services, 2018) People who do moderate and
vigorous PA# of people who meet the physical activity guidelines; prevalence of
physical activities and sedentary behavior.

Surveillance of physical activity is a core public health function that is necessary for
monitoring population engagement in physical activity, including participation in physical
activity initiatives. Surveillance activities are guided by standard protocols and are used
to establish baseline data and to track implementation and evaluation of interventions,
programs, and policies that aim to increase physical activity.

The three sources of public health surveillance data related to physical behaviors are
The International Physical Activity Questionnaire (IPAQ), Global Physical Activity
Questionnaire (GPAQ), National Health Interview Survey. Questions like what proportion
of adults in a population are active at recommended levels? How many report regular
walking? Do these proportions vary by age, sex, or race or ethnicity? What are
long-term trends in these values over time? Etc.


1. Paffenbarger, R. S. (2000, June 1). Jerry Morris: Pathfinder for health through an active
and fit way of life. British Journal of Sports Medicine. Retrieved March 14, 2022, from

2. Kohl, H. W., Murray, T. D., & Salvo, D. (2020). Foundations of Physical Activity and
Public Health. Human Kinetics.

3. Fontana L, Villareal DT, Weiss EP, Racette SB, Steger-May K, Klein S, et al. C.G.
Washington University School of Medicine, Calorie restriction or exercise: effects on
coronary heart disease risk factors. A randomized, controlled trial. Am J Physiol
Endocrinol Metab. (2007) 293:E197–202. doi: 10.1152/ajpendo.00102.2007

4. Kasapis C, Thompson PD. The effects of physical activity on serum C-reactive protein
and inflammatory markers – A systematic review. J Am Coll Cardiol. (2005) 45:1563–9.
doi: 10.1016/j.jacc.2004.12.077

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