How Exercise Affects the Systems of Your Body
Physical Health
 How well your body functions
 Why exercise?
 Can help prevent:




Cardiovascular disease
Certain cancers
Diabetes
High Blood Pressure
 Improves Stamina, Flexibility, and Strength
 Controls Weight
 Improves Quality of Life
 Affects both social and mental health
Physical Health
 Affects every system in your body
 Key systems to be discussed:
 Cardiovascular
 Respiratory
 Muscular
 Skeletal
 Nervous

Brain
Cardiovascular System
 Cardiovascular System – AKA the Circulatory System – is an
organ system that encompasses the heart and blood vessels of
the body
 Function - carries blood, oxygen, and nutrients to organs and
tissues of the body, and carries waste and carbon dioxide from
these tissues for removal from the body
 Heart causes blood to flow away from the heart
 Bodily movement causes blood to efficiently flow back to the heart
 Muscles pressing on veins help push blood back towards the heart
 The heart is a constantly working muscle
The Heart
 Any exercise will strengthen muscle
 More exercise = stronger heart
 Stronger heart = less work to do at rest
 Higher cardiac output – more blood is expelled from the
heart per beat
 Less work to do at rest = lower resting heart rate (RHR)
 More exercise = better blood and oxygen flow
Blood Vessels and Pressure
 Increased exercise will increase cardiac output and
lower heart rate
 Helps regulate fluid and promotes capillary formation
 Amount of fluid in blood greatly determines blood
pressure
 More fluid = more pressure
Respiratory System
 Function - to supply the blood with oxygen in order for
the blood to deliver oxygen to all parts of the body
 Made up of
 Mouth
 Nose
 Trachea
 Lungs
 Diaphragm
Respiratory System
 Improves lung capacity
 Blood flow increases to alveoli
 Allows better Oxygen / CO2 exchange
Respiratory System
 Controls mucus which may settle in the lungs
 Increases endurance of Diaphragm and Intercostals
Nervous System – The Brain
 More exercise = better blood flow to the brain
 Exercise causes the release of endorphins which make
you feel good
 Studies show consistent exercise = better brain
development in children
 Underuse will result in a decline in function
The Brain
 Exercise seems to slow or reverse the natural
declination of brain function starting in our twenties.
 New studies seem to show that adult brains are
capable of neurogenesis (creation of new brain cells)
 Adults were previously thought to be unable to do this
 Exercise is thought to jumpstart neurogenesis
 Exercise seems to prompt an increase in Brain-Derived
Neurotropic Factor (BDNF)
 Exercise does not have to be exhaustive!
The Brain
BDNF:
 Strengthens brain cells and axons
 Fortifies connections among neurons and sparks
neurogenesis
 Most people have higher levels of BDNF in blood after
exercise
 This does not fully explain all the brain changes
associated with exercise
Muscular System
 Helps with strength and endurance
 Supply and demand
 The more you exercise, the more demand there is on
your muscles which leads to an increase in strength and
endurance
 More exercise = more blood flow = increased muscle
growth
Diagram of a Skeletal Muscle
Muscular System
Increase workload = increased stress on muscles
2. Increased stress result in micro-tears in muscle fibers
3. Natural repair process repairs the tear
1.
a)
b)
Overcompensates by adding bigger cells to build a stronger
fiber.
Over time, this repeated process of teardown and re-build
will result in muscle growth
Hypertrophy – muscle growth

Your body does not actually make more muscle but the muscle fibers
which make up your muscle get larger
Muscular System
An established exercise routine results in an increase in
Mitochondria in muscles
 Mitochondria use oxygen to create energy


Glucose + Pyruvate + NADH = ATP
(adenosine triphosphate)
Process occurs because of the presence of oxygen
Increase in number of blood vessels in muscle tissue
Skeletal System
 Consists of:
 Bones, ligaments, and cartilage
 Functions - support, movement, protection, blood cell
production, calcium storage and endocrine regulation
Skeletal System
Diagram of a Bone
Skeletal System
 Bones
 Contain marrow that produce blood cells
 Ligaments
 Fibrous connective tissue attached to bones and many
internal organs


Helps limit movements induced by tendons
Keeps internal organs in place
 Cartilage
 Holds some bones together, helps in the formation of
bones in growing children and prevents bones from
rubbing each other.
Skeletal System
 Physical Activity promotes:
 Increased synovial fluid production
 Maintains and increases joint range of movement
 Increased bone density
 Stronger ligaments
Skeletal System
 Synovial Fluid – oil-like fluid produced at joints to
keep cartilage lubricated and nourished
 Production of synovial fluid is an acute (short-term)
response to exercise




More exercise means = more synovial fluid
Joints need regular exercise to stay lubricated, nourished and
healthy.
More fluid = better range of motion
Lack of exercise causes joints to “dry up”
Skeletal System
 Increased Bone Density
 Weight-bearing and cardiovascular exercises put stress
on bones
 Body responds by creating osteoblasts
 Osteoblasts – cells which build new bone and make
bones stronger and denser
 Increased bone density helps prevent osteoporosis
 Osteoporosis – weakening of bone
Skeletal System
 Stronger Ligaments
 Ligaments are exposed to the same stresses of exercise
 Slowly develop strength