Physiologic Changes Associated with Aging

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Personal Health Factors The Etiology of Chronic
Disease
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EXERCISE TESTING and PRESCRIPTION for CHILDREN
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What has prompted interest in PA and exercise in
the pediatric population?

• Recognition of the role of regular exercise in
  the present and future health of youth,
  especially childhood obesity
• NHANES (1999-2002) indicates 16 of children
  adolescents are overweight (more than tripled
  since 1980)
• Growing rates of participation in elite-level
  sports competition
• Awareness of the role of exercise testing
  intervention in CA with chronic diseases

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Somatic Growth and Biological Maturation

• Physiologically, children are not miniature
  adults.
• Substantial variability in growth status and
  maturity level for any given chronological age
• Physical activity and exercise (esp. weight
  bearing) are necessary for attainment of maximal
  genetic bone density
• Activity level has a negative/adverse impact on
  growth only if
• 1. activity level falls below a biological
  threshold, or
• 2. training is excessive (reduce growth potential)

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Physiological Differences

• Respiratory System
• Higher breathing frequency
• Lower tidal volume
• Lower ventilation
• Cardiovascular System
• Lower stroke volume
• Higher heart rate
• Lower cardiac output
• Lower lactate concentration
• Lower absolute VO2 values Higher or equal
  relative VO2 values

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Physiological Differences

• Temperature Regulation
• Larger surface area-to-mass ratio
• allows for greater heat exchange by convection
  and radiation
• Greater heat loss when environment is lower than
  body temperature
• Poor sweating capacity
• Activation of sweat glands occurs at higher temps
• Less sweat is produced
• Shorter tolerance time for exercise in
  temperature extremes

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Physiological Differences

• Neuromuscular-Skeletal System
• Exhibit less strength, power muscular endurance
• Nerve myelination is lower
• Motor unit activation is lower
• Testosterone levels are lower
• Fiber type distribution and number is fixed at or
  soon after birth
• Only 15 are undifferentiated at both
• Strength measurements
• Pre-pubertal vs peri- and post-pubertal

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Physiological Differences

• Metabolic System
• Lack of metabolic specialization
• Slower times for long distances
• Lower ability to generate maintain mechanical
  power
• Lower amounts of stored PC and glycogen
• Less economical at any given speed
• Use more O2 at any given speed
• Less able to facilitate anaerobic pathways
• Age has greater impact on anaerobic metabolism
  than aerobic metabolism

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• Benefits of Exercise
• Establish active lifestyle
• Weight management
• Protective effect against disease
• Fitness
• Stress management
• Increase peak bone mass
• Consideration in Selecting Physical Activities
• Age
• Attention span
• Motor development
• Muscular development
• Physical stature
• Fitness level

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Fitness Testing

• Field Tests for Children
• FITNESSGRAM and the Presidents Challenge Test
• H/F Component Field Test
• Cardiorespiratory Fitness 1 mile walk/run
• Muscular Fitness Curl-up test
• Pull-up/push-up test
• Flexibility Sit and reach test
• Body Composition BMI or skin folds

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Fitness Testing

• Graded Exercise Tests
• Ergometers (electronically braked) vs. TMs
• Variety of protocols are appropriate
• Bruce, Balke, McMaster, James Protocols
• Goals, objectives, measurements to be obtained
• Heart rate, Blood pressure, endurance time
• Physician present for serious rhythm disorders,
  aortic stenosis, CAD, heart disease
• Criteria for stopping a test are similar to those
  for adults

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Exercise PrescriptionLarge Muscular Activity

• 60 minutes of accumulated activity/day
• Participate in several bouts of PA lasting 15 min
  or more each day
• Participate in a variety of age-appropriate PAs
  designed to achieve optimal health, wellness,
  fitness and performance benefits.
• Adolescent girls may require additional support
  to be physically active
• Extended periods of inactivity are discouraged,
  esp. during the daytime hrs.

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To accomplish these goals

• Prefer short-term intermittent activities with a
  high recreational component and variety
• Best suited for repeated activities of varying
  intensities lasting a few seconds
• Allow to be naturally active (enjoyable)/
  encourage play outside The Exercise Menu
• Allow to control the intensity and duration of
  the activity
• Involve with organized activities where emphasis
  is placed on gaining basic motor and sport skill
  competency
• Provide active role models

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Exercise PrescriptionStrength Training

• Consider potential benefits of training and
  potential risks (weigh them)
• Benefits may include
• Strength gains
• Injury protection
• Improved sports performance
• Long-term salutary influence on infirmities
• Risks include
• Low back and growth plate injury
• acute chronic musculoskeletal injuries

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Strength Training Programs

• Adequate warm-up followed by close, continuous,
  trained supervision
• Emphasis on proper form, not the amount of
  resistance
• Higher repetitions per set
• no less than 8 reps/set ideally 8-15
  reps/exercise
• Adequate recovery between sessions
• frequency of no more than 2 to 3 days/week
• Inclusion of flexibility exercises, esp. during
  growth spurts
• Strength gains pre-pubescent - strictly neural

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Precautions

• Higher energy expenditure at any
  given submaximal intensity
• Excessive body heat and higher VO2/unit of body
  mass
• Greater susceptibility to heat stress
• Replace fluids every 15-30 minutes at a rate of
  100-150 ml
• Takes longer for children to acclimatize (poor
  sweating capacity)
• Expression of motor skills in sport
  recreational activities
• Monitor menstrual status in females

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Precautions

• Vulnerable to injury (esp. during growth spurts)
• Monitor growth rate to identify periods of
  accelerated growth
• Risk factors for overuse injury include
• significant changes in FITT (lt10 in training)
• inflexibility
• imbalance of strength and flexibility
• incorrect biomechanics and footwear
• 50 of overuse injuries are preventable

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EXERCISE TESTING and PRESCRIPTION for ELDERLY
PEOPLE
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Ed Rondthaler vs. the naked
mole rat
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THEORIES OF AGING

• The processes underlying aging (senescence) are
  largely unknown
• Biological Processes
• Cellular Theories
• Alteration in cellular genetic coding that
  results in abnormalities in synthesis of the
  cells various constituents
• Programmed cell death (apoptosis)
• Physiological Theories
• Autoimmunity
• Impaired neuroendocrine control mechanisms

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THEORIES OF AGING

• Wear and Tear
• Looks at the impact of damage from tobacco,
  pollution, too much food, not enough exercise,
  etc.
• Telomeres chunks
  of DNA on the ends
  of chromosomes that
  shorten every time
  the cell divides.
• Stress shortens
  telomeres, which
  hastens aging

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THEORIES OF AGING

• Wear and Tear, cont.
• Oxidative stress oxidants damage DNA, proteins,
  and lipids
• As we get older, we become less efficient at
  turning O2 into energy, creating free radicals
  that damage our cells.
• Glycation glucose sugar binds to proteins,
  resulting in the formation of AGEs ?
  deterioration in tissue protein function

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THE IMPACT OF AGING

• Data Collection
• Cross-sectional studies
• Longitudinal studies
• Deterioration of systems leads to
• Decreased exercise performance/ recreational
  activities/ sport
• Performance of normal daily activities
• Is there a way to preserve functional capacity
  maximize independence?

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THE IMPACT OF AGINGOverview of Pathophysiology

• The Heart
• Increased left ventricular hypertrophy (preserves
  resting SV)
• Decreased blood vessel elasticity ? increased
  resting exercising SBP mean BP
• Decreased resting and exercising Q
• Decreased exercising SV
• Increased peripheral resistance in vasculature
• Aortic stiffness

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THE IMPACT OF AGINGOverview of Pathophysiology

• Heart Rate
• No change in resting HR
• Decreased SNS stimulation of SA node
• Decreased maximal exercise heart rate
• Decreased Max VO2
• Decreased blood redistribution
• Reduction in muscle mass, capillary density,
  oxidative capacity
• Pulmonary System
• Decreased elasticity/stiffening of the chest wall
  
• Increased RV / Decreased VC

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THE IMPACT OF AGINGOverview of Pathophysiology

• Skeletal muscle and strength
• Decline in muscle strength
• Change in fiber type distribution
• Increasing unsteadiness
• Bone
• Decreased calcium content
• What accelerates bone loss?
• Development of osteoarthritis

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THE IMPACT OF AGINGOverview of Pathophysiology

• Joints and flexibility
• Degeneration of collagen fibers
• Connective tissue becomes less extensible
• Decreased range of motion
• Body composition and metabolism
• Decrease in lean body mass
• Progressive increase in body fat

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THE IMPACT OF AGINGOverview of Pathophysiology

• Renal function and Nervous System
• Predisposed to rapid dehydration
• Decreased reaction time and nerve conduction time
• Decreased sensory deficits

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Physiologic Changes Associated with Aging

• System Function Change
• Rest HR No change
• Max HR Lower
• Cardio- Rest C.O. Lower
• vascular Max C.O. Lower
• Rest SV No change
• Max SV Lower

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Physiologic Changes Associated with Aging

• System Function Change
• Rest BP Higher
• CV Exercise BP Higher
• Max VO2 Lower

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Physiologic Changes Associated with Aging

• System Function Change
• Respiratory RV Higher
• Vital Capacity Lower
• Total Lung
• capacity No change
• Respiratory
• frequency Higher
• Work of breathing Higher
• VentilationPerfusion Mismatch

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Physiologic Changes Associated with Aging

• System Function Change
• Musculo- strength Lower
• skeletal mass Lower
• flexibility Lower
• balance Lower
• bone density Lower

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Physiologic Changes Associated with Aging

• System Function Change
• Renal Kidney fxn Lower
• Acid-base cntl Lower
• glucose tolerance Lower
• drug clearance Lower
• cellular water Lower

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Physiologic Changes Associated with Aging

• System Function Change
• Metabolic BMR Lower
• Lean body mass Lower
• Body fat Higher

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Medical Disorders

• Cardiovascular
• HTN, Hypotension, CAD, Valvular Heart Disease,
  Dysrhythmias, Peripheral Arterial Disease
• Pulmonary
• Asthma, COPD, Pneumonia
• Musculoskeletal
• Arthritis, Degenerative Disk Disease,
  Osteoporosis, Degenerative Joint Disease

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Medical Disorders

• Metabolic/Endocrine
• Diabetes, Hypercholesterolemia
• Gastrointestinal
• Dental, Malnutrition, Incontinence, Diarrhea
• Hematologic/Immunologic
• Anemia, Leukemia, Cancer
• Neurologic
• Alzheimers Disease, Parkinsons Disease

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Major Benefits of Exercise

• Improves cardiovascular function
• Enhances work capacity and performance
• Reduces CAD risk factors
• Decreases morbidity and premature mortality
• Aids in weight management
• Builds muscle and strong bones
• Decreases stress, anxiety and depression
• Enhances self esteem and sense of well being
• Enhances quality of life
• Reduces risks of falls and complications in
  elderly

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Benefits of Training-Specificity

• Endurance Training
• Peripheral adaptations (increased
  capillarization, increased oxidative capacity)
• Central adaptations (increased LV compliance and
  mass,increased contractility, increased SV)
• Changes in body composition
• Resistance Training
• Increases in strength (most likely related to
  neural mechanisms than to hypertrophy)
• Specific programs for ADLs

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Factors to consider when selecting an exercise
protocol

• Characteristic Test Modification
• Low VO2max Start at low intensity
• Time to attain
• a steady state Long warm-up
• Increased fatigue Reduce total test time
• Monitor BP, HR Cycle ergometer
• Poor balance Cycle ergometer
• Poor ambulation Increase TM grade

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Factors to consider when selecting an exercise
program

• Mode
• Does not impose significant orthopedic stress
• The activity should be accessible, convenient and
  enjoyable
• Intensity
• Sufficient to stress (overload) the CVE,
  pulmonary and musculoskeletal systems without
  overtaxing them

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Factors to consider when selecting an exercise
program

• Intensity
• Use a measured maximal heart rate (HRmax) vs.
  age-predicted 55
• 40-70 of HR reserve
• Duration
• Several 10 min bouts throughout the day if
  difficulty sustaining
• Increase duration rather than intensity

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Management Medications in the Elderly
Dizziness Confusion/depression (diuretics,
anti-HTN) Fatigue and weakness (beta blockers,
diuretics) Postural hypotension (vasodilators,
nitrates, anti-HTN, diuretics) Involuntary muscle
movements Urinary Incontinence (anticholinergics,
diuretics) Increases in heart rate
(bronchodilators)