Prescription of Exercise for Health and Fitness

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Prescription of Exercise for Health and Fitness

• Chapter 19

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Learning Objectives

• Find out how physically active American adults
  are in relation to the medical communitys
  recommendations for fitness.
• Review the importance of receiving medical
  clearance before undertaking an exercise program

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Learning Objectives

• Learn methods of testing fitness levels via
  exercise tests
• Review the components of a sound exercise program
• Discover how to become more active and gain the
  benefits of regular exercise

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National Problem

• More than 60 of American adults are not
  regularly physically active.
• 25 of all adults are not active at all.
• Nearly 50 of American youths 12 to 21 years of
  age are not regularly vigorously active and
  physical activity declines during adolescence.
• (these numbers are steadily growing worse!)

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Kenneth Cooper, M.D.

• Founder of the Cooper Institute and author of the
  book, Aerobics, in 1968, which is credited with
  starting the fitness revolution in the U.S.

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Surgeon General Physical Activity and Health

• Published in 1996, recommendations included the
  following
• People of all ages, male and female, benefit from
  regular physical activity.
• Thirty minutes of moderately intense exercise
  (e.g., 30 minutes of brisk walking) on most, if
  not all, days of the week can improve health.
• Additional health benefits are gained with
  maintaining a regimen that is greater in volume
  and intensity.

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Importance of Medical Clearance

• Provides opportunity to check for early stages of
  disease
• Helps identify those with risk factors
• Helps develop an appropriate exercise
  prescription
• Helps to motivate when knowing your current BP,
  body fat, and blood lipid values
• Provides a baseline for changes in health

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Who Must Receive Medical Clearance?

• Men over 40
• Women over 50
• Anyone, any age, who has two or more risk factors
  for coronary artery disease (CAD) or symptoms or
  signs of cardiopulmonary disease

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Components of Medical Clearance

• CAD screening
• Physical examination
• Exercise ECG

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Major Symptoms or Signs Indicative of
Cardiopulmonary Disease
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Exercise ECGs

• Obtained while exercising on a treadmill or cycle
  ergometer
• Graded test by progressing rate of work from low
  up to maximal intensity
• Monitored for arrhythmias and CAD indicators that
  occur during exercise but not rest
• Consideration of sensitivity, specificity, and
  predictive value for specific subject

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ECG Screening in the Young

• The value of using an exercise ECG to screen for
  CAD in young, healthy individuals is
  questionable.
• The sensitivity and predictive value of an
  abnormal test are generally low in this
  population, where there is a low prevalence of
  CAD.

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ECG Screening in the Young

• A medical examination might not be necessary if
  moderate exercise is started gradually in people
  without symptoms of cardiopulmonary disease.

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Exercise ECG Test Sensitivity (SN), Specificity
(SP), and the Predictive Value (PV), of an
Abnormal Test
Test is with respect to CAD as verified with an
Arteriogram
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Exercise ECG Test Sensitivity (SN), Specificity
(SP), and the Predictive Value (PV), of an
Abnormal Test
Example 100 subjects tested 6 true positive 10
false positive 4 false negative 80 true
negative SN 6/(6 4) 60 SP 80/(10
80) 89 PV 6/(6 10) 38
Test Sensitivity SN TP/(TP FN) the
sensitivity is the proportion of tested
positives with all positive cases in the
population. A sensitivity of 100 means that the
test recognizes all sick people as such. Test
Specificity SP TN/(FP TN) the
specificity of a test is the probability that if
the person does not have the disease, the test
will be negative. Predictive Value PV
TP/(TP FP) the predictive value is the
probability that in case of a positive test, that
the patient really has the specified disease.
As a practitioner, which test is more
meaningful?
Test is with respect to CAD as verified with an
Arteriogram
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Components of Exercise Prescription

• Type- usually one or more CV endurance activities
  plus resistance training
• Frequency- 3 to 5-d per wk (or more)
• Duration- 20 to 30 mins at appropriate intensity
  is optimal (optimal is defined as the greatest
  benefit for time invested)
• Intensity- generally 55 or 60 to 90 of HRmax
  or 40 or 50 to 85 of VO2max
• Although, varies individually and health benefits
  can occur at lower intensities

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Minimum Threshold for Benefits

• A minimal threshold for frequency, duration, and
  intensity must be reached to gain aerobic
  benefits from an exercise.
• This threshold varies individually.
• For this reason, relatively unfit individuals
  should use preconditioning activities such as
  walking, jogging, aerobics, or cycling to gain
  fitness before switching to a sport or
  recreational activity.

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Disease Risk Model (e.g. CAD, hypertension, Type
II Diabetes)
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Monitoring Exercise Intensity

• Training heart rate (THR)
• Can use linear relationship with VO2max
• Can use the Karvonen method of maximal heart rate
  reserve
• Can set a THR range
• Metabolic equivalents (MET)- Oxygen requirements
  of an activity and its intensity
• Ratings of perceived exertion (RPE)-Subjective
  rating of the difficulty of work

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THR at 75 VO2max
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Karvonen Method

• Instead of using VO2, THR is determined as a
  percentage of the HRmax reserve.
• Maximal heart rate reserve HRmax - HRrest
• To train at 60 of maximal heart rate reserve
• THR60 HRrest 0.60(HRmax - HRrest)

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Heart Rate Range

• Establishing a training heart rate range (THR) is
  a sensible way to monitor exercise intensity.
• Start exercise with your HR in the low end of the
  range and progress to the upper end of the range
  over time.

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Metabolic Equivalents (METS)
1.0 MET resting metabolic rate (3.5 ml
O2/kg/min)
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The Borg RPE Scale

• Individual subjectively rates how hard he/she is
  working when used correctly, it can be
  reasonably accurate

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Classification of Exercise Intensity Comparing
Three Methods
Based on 20 to 60 min of endurance activity
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Use It or Lose It

• One of the best ways to ensure health benefits
  from exercise is to continue a consistent
  exercise program throughout life.
• Health benefits are rapidly lost once an exercise
  program is discontinued.

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Exercise Program

• 3-4 days per week
• Warm-up and stretching
• Endurance exercise
• Cool-down and stretching
• Alternate days
• Flexibility training
• Resistance training
• Recreational activities

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Warming Up and Cooling Down

• Low intensity callisthenic-type exercises and
  stretching
• Can decrease risk of injury and muscle soreness
• Warm-up prepares the cardiorespiratory and muscle
  systems for more intense exercise.
• Active cool-down prevents blood from pooling in
  the extremities.

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Rehabilitation Through Exercise

• Cardiopulmonary disease
• Cancer
• Obesity
• Diabetes
• Renal disease
• Arthritis
• Cystic fibrosis
• Transplants