This document provides an overview of exercise physiology by discussing key topics such as the history of the field, energy systems, the nervous system, endocrine system, and skeletal muscle system. It traces the evolution of exercise physiology through the work of scientists from the 1700s to present day. It also explains how the body produces energy during exercise through three main pathways and how training can enhance these pathways.

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Chapter 2
Exercise Physiology

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Introduction to
Exercise Physiology
 Physiology
 The study of human function
 Molecular level or whole organism level
 Exercise
 Form of physical exertion that can be carefully
quantified
 Exercise duration, intensity, type/mode, frequency

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Exercise Physiology
 Definition:
the study of how the body functions during physical
exertion that is carefully quantified
 Exercise science curriculum incorporates exercise
physiology as an upper level course (junior or
senior) in addition to the study of biology,
chemistry, anatomy & physiology,

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History—Exercise Physiology
 Field has evolved through findings of several
different scientists
 1700’s Antonie Lavoisier
 Discovery that oxygen uptake increased with physical
exertion
 Mid to late 1800’s Fernand LaGrange—1st
textbook
 The Physiology of Bodily Exercise
 1879 Dudley Sargent
 Developed a physical fitness program at Harvard
University based on individual prescription

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History—Exercise Physiology
 1891 George Fitz
 Exercise physiology laboratory created at Harvard.
Courses in exercise physiology and laboratory research
were instructed. This combination is continues today.
 20th
Century
 Finding that muscle activity is powered by carbohydrate not
heat (previously believed)
 1900’s prominent researchers traced to Europe
 Founded 1954
 1920 August Krogh, Danish physiologist
 Studied muscle activity and blood flow, Noble Prize

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History—Exercise Physiology
 1920’s
 Archibald Vivian Hill, British physiologist
 Nobel Prize, studied muscle force and movement speeds
 Pioneer in studying VO2 responses pre and post running
 John Haldane, European physiologist
 Influential development of respiratory gas analyzer
 Studied carbon dioxide on breathing regulation
 Otto Meyerhof, German physiologist
 Shared Noble Prize with Hill
 Conducted studies on energy metabolism

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History—Exercise Physiology
 1927 David B. Dill, biochemist from Stanford
 Harvard Fatigue Laboratory, legendary
accomplishments in exercise physiology.
 Studied the physiological, psychological, sociological
factors with manual work.
 Research in metabolic responses to exercise,
environmental stress, aging induced changes, blood-
gas and acid-base chemistry
 Remained open for 20 years
 Fundamental in the spread of the field along with many
European researchers

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History—Exercise Physiology
 Same timeline as Harvard Fatigue Laboratory European researchers:
 Erik Howhu-Christensen
 One of 1st
researchers to study fuel patterns during exercise
 Became faculty at Gymnastik-och Idrottshogskolan in Stockholm and
mentor to many great researchers
 Per-Olof Astrand,
 The Textbook of Work Physiology
 Astrand-Rhyming Submaximal Exercise Test
 Ehrling Asmussen and Marius Nielsen
 Joined faculty University of Copenhagen
 Asmussen focus was exercise and muscle function
 Nielsen studied temperature regulation with exercise in hot and cold
environments
 Bengt Saltin
 Leading contemporary exercise physiologists

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History—Exercise Physiology
 1950’s
 American College of Sports Medicine
 1954 held first scientific meeting
 Goal was to expand the knowledge of exercise
responses in humans
 Atherosclerosis
 Evidence from the Korean War that young male
casualties showed evidence of coronary artery
disease
 CVD problems were thought linked to aging, findings
revealed that disease develops early in life

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General Course Content
 Energy
 Nervous
 Endocrine
 Skeletal muscle
 Cardiovascular
 Respiratory

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The Energy Systems
 Energy for exercise is derived from the
breakdown of stored resources
 Fat and carbohydrate (protein not primary source)
 Chemical reactions transfer potential to ATP
 ATP—adenosine triphosphate
 ATP is the body’s usable form of energy

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The Energy Systems
 ATP is degraded to adenosine diphosphate
(ADP) and inorganic phosphate (Pi)
 Muscles can use three different pathways to
make ATP
 Phosphagen
 Glycolytic
 Oxidative

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The Energy Systems
 3 energy pathways
 Anaerobic pathways: phosphagen and glycolytic
 Do not require oxygen
 Occurs in cell’s cytoplasm
 Phosphagen pathway
 Phosphate molecule is transferred to ADP to make ATP
 Glycolytic pathway
 Requires more steps, involves the breakdown of a glucose to
produce ATP.
 Results in formation of ATP and pyruvate
 Not useful for prolonged exercise

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The Energy Systems
 3 energy pathways
 Aerobic pathway: oxidative pathway
 Oxidation occurs in mitochondria
 Requires oxygen
 Glycolysis and Kreb’s cycle oxidizes glucose (from
carbohydrate) or fatty acid (breakdown of stored fat)
and is completed with the electron transport chain to
produce ATP
 Provides energy for endurance activities

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The Energy Systems
 Exercise Training
 Specific energy pathways in the muscle can be enhance
with training
 Anaerobic (sprint) training increase cell’s ability to
produce energy from the phosphagen and glycolytic
pathways
 Aerobic (endurance) training will increase the ability to
synthesize ATP via oxidation
 Will increase muscle glycogen concentration
 Enhance ability of muscle to resist fatigue during prolonged
exercise

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The Nervous System
 Primary control system for physiological
function
 Brain, spinal cord, all peripheral nerves
 Central Nervous System
 Brain and spinal cord
 Peripheral Nervous System
 All neurons that transmit information to (sensory
branch) and from (motor branch) the spinal cord

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The Nervous System
 Peripheral Nervous System
 Somatic nerves
 Sensory information (consciously sensed) light, taste,
touch, sound
 Voluntary motor transmission
 Skeletal muscles
 Autonomic nerves
 Not consciously controlled: pressure, chemical
changes, heart, lungs, blood vessels, organs of
digestion
 Sub-divided: parasympathetic and sympathetic

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The Nervous System
 Autonomic Nerves
 Parasympathetic
 Autonomic regulation at rest
 Sympathetic
 Activated during stress such as exercise
 Example of autonomic function:
One goes from resting position to increasing exercise
intensities.

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The Nervous System
 Exercise training can alter nervous system function
 Strength training
 Adaptations in skeletal muscle to increase strength and recruitment
of muscle fibers through the nervous system
 Endurance training
 Can reduce the amount of sympathetic activation during submax
exercise since endurance training reduces the overall stress on the
body during exercise
 Exercise can alter both somatic and autonomic nerves

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The Endocrine System
 Glands secrete hormones into the blood
 Works with the nervous system to regulate
physiological function through hormones and
glands.
 Hormones travel through circulation to their
target organ
 Hormones bind to receptors and initiate cell
activity

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The Endocrine System
 Hormones and exercise
 Pituitary gland
 With exercise secretes growth hormone which influences fuel use
with exercise
 And antidiuretic hormone will increase water conservation during
exercise
 Adrenal gland
 Cortex secretes cortisol and alodosterone
 Medulla secretes epinephrine (adrenaline) and norepinephrine
(noradrenaline)
 Pancreas
 Secretes insulin hormone in response to increase blood glucose
levels
 Exercise causes insulin levels to decline
 Secretes glucagon hormone when there is a decrease blood
glucose levels
 Glucagon increases the amount of glucose formed and released by the liver

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The Endocrine System
 Exercise training response to the endocrine
system
 Endurance training
 Reduce the release of epinephrine & norepinephrine
 Resistance training
 May influence the body’s response to the hormones
testosterone, insulin-like growth factor-I, and cortisol
 Due to increase muscle mass

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The Skeletal Muscle System
 Comprises 40% of total body mass
 Together with nervous system, provides movement
 Functional unit of muscle is the muscle fiber
 Single muscle fiber is comprised of sacromeres
 Sacromeres contain the contractile elements actin
and myosin
 Once activated by neural stimulation, myosin and
actin filaments attach and pull toward the
sacromere
 Then, muscle fiber shortens and force is generated

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The Skeletal Muscle System
 Human skeletal muscle is comprised of 3
different types of fibers
 Slow twitch (Type I)
 Good endurance
 Reliance on oxidative metabolism to produce ATP
 Fast twitch (Type IIa)
 Combination of good endurance and power
 Fast twitch b (Type IIb)
 Most powerful fibers, poor endurance

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Skeletal Muscle Fiber Type
Classification Schemes
Twitch Term Energetic
Term
Color Term Generic
Term
Slow twitch (ST) Slow, oxidative
(SO)
Red Type I
Fast twitch a (FTa) Fast, oxidative,
glycolytic (FOG)
Intermediate Type IIa
Fast twitch b (FTb) Fast glycolytic
(FG)
White Type IIb

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The Skeletal Muscle System
 Exercise training response can impact
system
 Aerobic training
 Will increase endurance capacity of all three fiber
types
 Strength training
 Will not change muscle fiber but will result in increase
in strength due to increase in muscle mass

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The Cardiovascular System
 Delivers oxygen and nutrients and removes
carbon dioxide
 Consists of heart, blood vessels and blood
 Exercise will affect each component
 HR x SV = Q
 Exercise increases Q
 Increase in Q and HR directly proportional to
exercise intensity
 Increase in Q increase BP

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The Cardiovascular System
 HR—heart rate
 SV—stroke volume
 Amount of blood pumped out of heart with each beat
 Q—cardiac output
 Vasoconstriction occurs in arterial blood vessels in
viscera
 Vasodilation occurs in blood vessels of working
skeletal muscles
 This causes changes in blood flow patterns,
shunting more blood to working skeletal muscles

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The Cardiovascular System
 Exercise training response
 Aerobic training
 Heart pumps stronger
 Blood volume expands
 Increase in capillaries
 Submaximal exercise: HR decreases and SV increases
 Maximal exercise: HR unchanged or decreases, SV
increases, Q increases

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The Respiratory System
 Lungs responsible for ventilation and
diffusion
 Comprised of lungs and airways that conduct
air flow into the lungs
 Ventilation—process of drawing air into the
lungs
 Diffusion—process of oxygen and carbon
dioxide are exchanged between blood and
alveoli (inner most region of lung)

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The Respiratory System
 Airways that conduct air in and out of lungs
dilate, this reduces resistance to air flow.
 Additional airways open and increases
ventilation
 Diffusion of oxygen and carbon dioxide
between alveoli and capillaries occurs due to
pressure differences

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The Respiratory System
 Exercise training responses
 Aerobic training
 Increase maximal capacity of lungs to increase tidal
volume and respiratory rate
 Training will enhance the rate of oxygen diffusion out
of the lungs and into the blood
 Respiratory system and cardiovascular system both
increase capacity with increasing exercise intensities

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Additional topics studied
 Nutrition for health and
performance
 Body composition
techniques
 Physiological response
to environmental stress
 Exercise testing
protocols
 Exercise prescription
models
 Exercise responses in
special populations
 Exercise and aging
 Pediatric exercise
responses
 Exercise effects gravity
 Sports training &
performance
 Metabolic disorders
 Bone health

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Professional Organizations
and Certifications
 Students should investigate possible
organizations that fit the need for their future
direction
 Certifications can be important for many job
descriptions
 Many employers in the clinical, education,
health promotion fields are looking for
candidates with both strong academic
standing with certifications

35. © 2010 McGraw-Hill Higher Education. All rights reserved.
Professional Organizations
and Certifications
 American College of Sports Medicine
(ACSM)
 Various specialties: medical doctors, allied
health professionals, fitness professionals,
exercise physiologists, biomechanists, sport
psychologists, athletic trainers
 Journals
 Medicine and Science in Sports and Exercise
 Exercise and Sport Sciences Reviews
 Health & Fitness Journal

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Professional Organizations
and Certifications
 ACSM certifications
 ACSM Certified Personal Trainer
 ACSM Certified Health Fitness Specialist
 ACSM Certified Clinical Exercise Specialist
 ACSM Registered Clinical Exercise Physiologist

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Professional Organizations
and Certifications
 National Strength and Conditioning Association
(NSCA)
 Various specialties: strength coaches, sport
coaches, sport scientists, researchers, educators,
sport medicine professionals, allied health
professionals, students, business owners, exercise
instructors
 Journals
 Strength and Conditioning Journal
 Journal of Strength and Conditioning Research
 NSCA Bulletin
 NSCA’s Performance Training Journal

38. © 2010 McGraw-Hill Higher Education. All rights reserved.
Professional Organizations
and Certifications
 NSCA’s certifications
 Certified Strength and Conditioning Specialist
(CSCS)
 NSCA-Certified Personal Trainer (NSCA-CC)

39. © 2010 McGraw-Hill Higher Education. All rights reserved.
Professional Organizations
and Certifications
 American Society for Exercise Physiology (ASEP)
 Founded 1997
 Journals
 Journal of Exercise Physiology-online
 The Professionalization of Exercise Physiology-online
 ASEP Newsletter
 One certification
 Exercise Physiologist Certified (EPC)

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Professional Organizations
and Certifications
 American Alliance of Health, Physical Education,
Recreation and Dance (AAHPER)
 Founded 1885
 Six associations:
 National Association for Sport and Physical Education (NASPE)
 American Association for Health Education (AAHE)
 National Dance Association (NDA)
 American Association for Physical Activity and Recreation
(AAPAR)
 National Association for Girls and Women in Sports (NAGWS)
 Research Consortium (RC)

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Professional Organizations
and Certifications
 American Association of Cardiovascular and
Pulmonary Rehabilitation (AACVPR)
 Cardiopulmonary rehab, clinical exercise
physiology
 No certifications, AACVPR works closely with
ACSM guidelines and certifications
 Journal
 Journal of Cardiopulmonary Rehabilitation

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Professional Organizations
and Certifications
 American Physiological Society (APS)
 Founded 1887
 Journals
 16 different journals
 Journal of Applied Physiology
 American Journal of Physiology

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Professional Organizations
and Certifications
 North American Society for Pediatric Exercise
Medicine (NASPEM)
 Physicians and allied health professionals who
apply testing & therapy in children with
cardiopulmonary disorders
 Focus on acute responses and chronic adaptations
with diseases and disorders
 No Certification
 Journal
 Pediatric Exercise Science

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Fitness Related Organizations
and Certifications
 American Council on Exercise (ACE)
 Certifications
 ACE Personal Trainer
 ACE Group Fitness Instructor
 Lifestyle and Weight Management Consultant
 Advanced Health and Fitness Specialist

45. © 2010 McGraw-Hill Higher Education. All rights reserved.
Fitness Related Organizations
and Certifications
 Aerobics and Fitness Association of America
(AFAA)
 Certifications
 Several certifications
 Personal Trainer Certification
 Primary Group Exercise Certification

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Careers in Exercise
Physiology
Many career options for different levels of study (select examples):
Personal trainer Bachelors
Fitness instructor Bachelors, Masters
Sports consultant Bachelors, Masters, Doctorate
Exercise physiologist Masters, Doctorate
Clinical exercise physiologist Bachelors, Masters, Doctorate
Exercise technologist
or stress testing technician
Bachelors, Masters
Exercise specialist Bachelors, Masters
Wellness counselor Bachelors, Masters
Professor Doctorate
Physical therapist/Occupational therapist Bachelors, Masters, Doctorate in Physical or Occupational
Therapy
Medical doctor Bachelors & Medical School
Chiropractor Chiropractic School
Nursing Bachelors plus degree in nursing