Physical Activity

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Physical Activity
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Terms

• Physical activity any bodily movement produced
  by skeletal muscles that results in energy
  expenditure. Sometimes measured as lifetime
  physical activity (LTPA)
• Sedentary Lifestyle hyper- couch potatoism
• Exercise planned, structured, and repetitive
  bodily movement done to improve or maintain one
  or more components of physical fitness

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Terms Continued..
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Health Related Components Body composition Cardiov
ascular endurance Muscle strength Flexibility
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• What evidence exists to support the health
  benefits of flexibility and weight training and
  how do these benefits compare to benefits from
  cardiovascular endurance?

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Literature Summary of Strength Training (by
strength of the available evidence)
The Presidents Council on Physical Fitness and
Sports Research Digest , Series 2, no. 8, Dec,
1996
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Recommended Amount of Strength Training

• ACSM, AHA, Surgeon General suggest
• One set of 8-12 reps of 8-10 exercises 2-3
  times/week
• 10-15 reps for persons over 50 years of age

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Literature Summary of flexibility (by strength
of the available evidence)
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• There is practically no data on the health
  benefits of flexibility, but much anecdotal
  evidence that it may be useful in preventing and
  treating low back pain.
• What about sports injuries?

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• What is the difference between fitness and
  physical activity?
• How are they measured?
• What do they represent?
• Which is used in research?

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Maximum Oxygen Uptake

• 10-50 of Max VO2 score may be genetic
• Is an accurate measure of cardiorespiratory
  fitness, but not physical activity
• Does physical activity lead to fitness, or visa
  versa?

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Physical Activity, U.S. Adults (2000 BRFSS,
Age-Adjusted)
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Physical Inactivity by Age (2000 BRFSS)
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Physical Inactivity by Income(2000 BRFSS,
Age-Adjusted)
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Physical Inactivity by Race/Ethnicity (2000
BRFSS, Age Adjusted)
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Physical Inactivity by Region BRFSS 2000
26.7
27.6
24.8
29.9
South
Age-adjusted
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Trends in Physical Activity
http//www.cdc.gov/mmwr/preview/mmwrhtml/mm5009a3.
htm
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Bad news

• Despite our efforts to encourage increased
  physical activity, industrialized nations are no
  more physically active then they were 20 years ago

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Why is it so hard for people to get regular
exercise?

• Lack of time
• Inconvenient
• Self conscious
• Poor health
• Lack of facilities
• Poor weather

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What Do We Do About It?

• Individual behavior change strategies
• Community/worksite level strategies
• Policy level changes
• Environmental changes

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What are the Benefits of Regular Exercise?

• Whats in it for me?
• Physical benefits
• Mental benefits
• Social benefits
• Spiritual benefits

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Known Benefits

• Reduces the risk of dying prematurely.
• Reduces the risk of dying prematurely from heart
  disease.
• Reduces the risk of developing diabetes.
• Reduces the risk of developing high blood
  pressure.

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• Helps reduce blood pressure in people who already
  have high blood pressure.
• Reduces the risk of developing colon cancer.
• Reduces feelings of depression and anxiety.
• Helps control weight.
• Helps build and maintain healthy bones, muscles,
  and joints.
• Helps older adults become stronger and better
  able to move about without falling.

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• Improves the quality of sleep
• Helps reduce stress and provides some protection
  against stress
• Helps improve self-concept
• Improves quality-of-life

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Studies on CVD and Physical Activity

• 24 prospective cohort studies
• Sedentary living is linked to CVD
• Inactive have a 2-fold increase in risk compared
  to active men and women
• Increased physical activity lowers risk,
  decreased physical activity increases risk

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Fitness and CVD Deaths
Deaths per 1000
JAMA 262(17)2398-2402,1989
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LTPA/CRF and Cancer Studies

• There is an inverse relationship between LPTA/CRF
  and colon cancer
• Sedentary men have twice the risk of colon cancer
• LPTA/CRF may decrease prostate cancer risk

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Why does physical activity reduce colon cancer
risk?
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• Increased transit time by stimulating colon
  peristalsis
• Shortens time cancer causing chemicals in fecal
  matter contact the cells of the colon
• People who exercise have less constipation

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Cont..

• Many who exercise regularly also consume more
  dietary fiber, but even with control for fiber,
  physical activity reduces colon cancer risk
• The more calories a person eats the higher the
  risk. People who exercise eat less than
  non-exercising obese individuals

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Other Cancers

• 3 of 4 studies on lung cancer found a
  relationship
• Half the studies found an inverse relationship
  with breast cancer, the other half found no
  relationship
• There is no association with cancers of cervix,
  stomach, or bladder

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Fitness and Cancer Deaths
Deaths per 1000
JAMA 262(17)2398-2402,1989
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Fitness and All-cause Mortality
Deaths per 1000
JAMA 262(17)2398-2402,1989
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LTPA/CRF and Diabetes

• 9 studies-- most found that LTPA/CRF are related
  to a reduction in the risk of developing type II
  diabetes

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What About Stroke?

• 9 studies, the majority have not supported a
  dose-response association between LTPA and stroke
  in men and women
• Three studies showed a U shaped association

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The U Shaped Stroke/Physical Activity Curve
Stroke incidence
moderate
low
high
very high
Physical Activity
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• The Surgreon Generals report states, the
  existing data do not unitedly support an
  association between physical activity and risk of
  stroke

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The Dose Response of Fitness
Proven Health Benefits
low
moderate
high
Fitness level
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So, How Much Physical Activity Should We Get?

• Every American adult should accumulate 30 minutes
  or more of moderate-intensity physical activity
  on most preferably all days of the week.
• Even those who currently meet this standard may
  derive additional health and fitness benefits by
  becoming more physically active or including more
  vigorous activity

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Moderate Intensity Physical Activities

• Racket sports, such as table tennis
• Golf (walking the course)
• Fishing (standing and casting, walking, or
  wading)
• Swimming (with moderate effort)
• Cycling (at a moderate speed of 10 miles per hour
  or less)
• Canoeing or rowing (at a speed of about 2-3.9
  miles per hour)

• Walking briskly (3-4 miles per hour)
• Conditioning or general calisthenics
• Home care and general cleaning
• Home repair, such as painting
• Mowing the lawn (with power mower)
• Gardening
• Dancing

Journal of the American Medical Association,
1995, Vol. 273, page 404.