Exercise
Dr Reed A Berger
Human beings have evolved with movement as a necessity for survival
e.g. to obtain food, to escape predators
thus, numerous systems in the body are sensitive to movement.
Today, why do people exercise?
Athletic/Artistic Performance
Physical appearance
How can we increase exercise for health reasons?
education - require PE for schools?
support - physicians, family
research
Health
Benefits of Exercise
Increased strength and muscular
endurance
 Increased BMD—osteoporosis
 Aging—decreased falls, increased
independence, increased ADL
 Increased BMR—LBM
 Appearance, self esteem

Technology—fewer demands placed on
musculoskeletal and CV systems
 2-3 generations ago—manual labor
 Stairs, elevators, cars
 Recreation—playing ball, jumping, hide-nseek vs. video games, internet
 Convenience and fast foods

Automation—decreased muscular
demands
 Body adapts—increased fast, weaker
 Scheduled exercise used to not be needed
with manual labor
 Today, have to “give back” the leisure time
gained thru technology and purposely
stress the muscular system

I. Basics of Exercise Physiology
Exercise is a complex molecular, cellular and systemic
physiological stimulus
With every single bout of exercise, skeletal muscles, heart, brain, vascular
tissue, bone, liver, etc. experience some form of environmental “stress”.
The type and magnitude of an adaptation or response to exercise thus
results from a sum total of all these contributing factors.
Some examples include:
- mechanical, stress/strain
- temperature
- pH
- redox state
- free radical production
- hormones/growth factors
- calcium
Specificity of Exercise: Adaptations that occur in response to
training are specific to the nature of the training stimulus
Cardiovascular fitness: requires that the person
train in a manner that challenges heart rate, cardiac
output, capillarity … with the underlying change being
improved oxygen delivery to working tissues
Muscular strength: requires that the person train in a manner
that challenges the recruitment and force output of specific
muscle groups … with the underlying change being increased
muscle mass.
The corollary to this is that training for endurance will not
augment strength or vice versa.
Cardiovascular fitness - endurance type activities: fuel challenging
large muscle mass
repetitive
lower intensity
walking, running, swimming, cycling
Muscular strength: high resistance, high force output
focus on muscle groups not on systemic “exercise”
e.g. knee extensors vs. flexors
Can a type of exercise be both strength and endurance?
yes BUT the effectiveness of any one form of activity to elicit
a specific adaptation is dependent on the endurance/strength starting
state of the individual.
Basic Principles of Exercise Training
Frequency - how often is the exercise performed
each week? For cardiovascular training effects
3-4x per week is suggested
Intensity - the exercise must be performed at a level that
challenges the cell/tissue/system for adaptations to occur.
Totally dependent on starting state. Lower the starting fitness
level the lower the starting intensity. Must build to continue
adaptations. Most important variable in training regimen for most.
Duration - length of each training session. For cardiovascular
Adaptations it is suggested to start at 30 minutes/session
MORE IS NOT NECESSARILY BETTER!
overtraining/system failure
Known adaptations to endurance exercise
Skeletal Muscle
 mitochondria
 capillary density
 oxidative enzymes
Brain (very new studies)
 neurogenesis
 protection from seizures, injury
Heart
 heart volume
 max stroke volume
 max cardiac output
 resting heart rate
 blood pressure
Bone
 density? Type of exercise
What is Maximum Oxygen Uptake?
VO2 Max
Maximal amount of oxygen consumption per minute
The more muscle used the higher the oxygen use
Predictor of performance?
Correlates with changes in cardiac output
Training will result in an increase
cardiac indices (CO, SV)
skeletal muscle contribution (mito)
ventilatory contribution?
Known adaptations to resistance exercise
Brain/Neural
 improved recruitment
Skeletal Muscle
 Fiber size
 Mitochondria?
Bone
 density
Role of exercise in weight and/or body fat control
Calories in vs. Calories out
Exercise can increase caloric expenditure
Exercise can spare loss of lean body mass during
times of caloric deficit
Increases in lean body mass will increase basal metabolic rate
BUT …. 10lbs of lean body mass will lead to about 70-80kcal/day
ALL forms of exercise will burn fat, even at Max VO2
Amount of fat burned during exercise is NOT important.
Total calories used during exercise IS important
a
For patients/clients, pick an exercise/activity modality that
they will do and do regularly. Type of exercise less important
Exercise prescription
To treat various diseases
 Primary prevention—PE class
 Clinically—discuss exercise
 Work—corporate wellness
 End of college, athletic endeavors—need
to have scheduled exercise
 60 min daily

Aerobic and resistance
 Convenient
 Traveling
 Pedometer
 Minutes per day
 Intensity, duration, frequency (need to
vary)

Routine exercise
Improves tissue oxygen uptake
 HDL
 LDL
 TG
 BP
 Glycemic control

Decreased risk of CA
Endometrial
 Breast
 Colon
 prostate

Cognitive benefits







Better adjusted
Cognitive tests
Decreased CV response to stress
Anxiety
Depression
People who were active and became inactive
were 1.5x more likely to become depressed
CAD and depression
Cognitive cont’d
Improves self confidence
 Self esteem
 Decrease CV and neurohormonal
response to stress
 Short bouts of exercise—cognitive
improvement

compliance
Long term adherence to exercise
 Decrease with age, minorities, females,
disabled, chronic dz
 Exercise program—50% cont for >6 mo

Types of exercise
Occupational, recreational, sports
 Aerobic
 Anaerobic—sprint
 Isometric—wts

Resistance training
Resistance to contracting muscles to
stimulate them for increased strength
 Injury risk—decreased
 Lean tissue and aging
 Heart conditions—don’t strain or hold
breath

How to make exercise a lifetime
activity
Pick activity that is enjoyable and uses
most muscles
 Vary duration, intensity
 Group classes
 Music
 Walk the dog!
 Set goals—health, appearance,
cholesterol

Elderly
Joint flexibility
 Muscle strength
 LBM
 Balance
 Prevention of injury

Pulmonary dz
Low workloads, short duration
 Frequent intervals
 Supplemental O2

Maternity

Maternal
Increased CV fxn
 Decreased wt gain and fluid
 Mental state
 Labor
 Recovery
 fitness

maternity

Fetus
Decreased fat
 Improved stress
 Neurobehavioral maturation

osteoporosis
BMD
 Muscle—balance, falls, fracture
 Works with estrogen, diet
 Wt bearing

CAD
Primary and secondary prevention
 Increased CV functional capacity and
decreased myocardial O2 demand
 Lipids, DM, obesity
 BP—8-10 mmHg
 Inactivity is independent risk factor for
CAD
 Sedentary have greatest CVD mortality

III. Application for Health Care
Obesity
Type II Diabetes
- Obesity is reaching "epidemic proportions” in the United
States
- could soon cause as much preventable disease and death as
cigarette smoking.
For the vast majority of individuals, overweight and obesity
result from excess calorie consumption and/or inadequate physical activity.
Unhealthy dietary habits and sedentary behavior together account
for approximately 300,000 deaths every year.
Exercise and Type II Diabetes
Position statement ACSM
About 10.3 million diagnosed cases and about 5.4 million undiagnosed
Accounts for 90-95% of all cases of diabetes
Characterized by insulin resistance and moderate insulin deficiency
Skeletal muscle: site of about 80-90% of glucose uptake
insulin and contraction act INDEPENDENTLY to increase
GLUT4 translocation and glucose uptake.
Ideal target for exercise and/or pharmacological therapies
Acute Effects of Physical Activity
Glucose Levels
Most obese Type II diabetics experience decreases in blood
glucose following mild-moderate exercise
magnitude of effect is dependent on duration and intensity
blood glucose increases with short term high intensity exercise
Insulin resistance
Insulin resistant individuals have 35-40% reduction in
insulin mediated glucose uptake
Low to moderate intensity exercise improves insulin sensitivity
High intensity exercise variable response
Transient effect (about 72 hrs) so requires regular activity
not really the “trained state”
Physiological Benefits of Exercise for those with Type II Diabetes
Lower resting heart rate
Lower submaximal exercise heart rate
Increased stroke volume
Increased cardiac output
Enhanced oxygen extraction
Lower resting BP
Lower exercise BP
Influence lipid profile
Psychological Benefits of Exercise
Reduced stress response to psychosocial stimuli
Lessened sympathetic nervous system activation to cognitive stress
Reductions in depression
Improved self-esteem
Reduction in emotional perturbations to stress
Contribute to sustained behavioral changes and adherence
Exercise and Chronic Diseases
Booth et al., 2000
Cardiovascular Disease
Type II Diabetes
Obesity
Obesity related diseases
Aging
While all these diseases have some contribution from
genetic the rapid increases in the last 20+ years are
due to environmental factors.
Sedentary living is responsible for about 34% of deaths due to
coronary heart disease, colon cancer and Type II diabetes
CDC has concluded that “physical inactivity is one of the major
underlying causes of premature mortality in the US”
Take home message
1. Consider exercise/physical activity for both
disease prevention as well as treatment
2. When considering exercise think movement
or activity not athletic performance
3. Consider the importance of exercise
for children. Growing evidence for mental as well as
physical development. Educate for healthy lifestyle
• Good resource for exercise and health information
American College of Sports Medicine www.acsm.org