Cardiovascular System and Exercise

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Cardiovascular System and Exercise
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Five Functions

• During exercise the cardiovascular system has 5
  functions
• Deliver oxygen to working muscles
• Oxygenates blood by returning it to the lungs
• Transports heat from the core to the skin
• Delivers nutrients and fuel to active tissues
• Transports hormones

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Effect on the Cardio-Respiratory System

• O2 demand increases
• Metabolic process speeds up
• More waste created
• More nutrients used
• Increase body temperature
• For your body to perform as well as possible
  these changes must be regulated by the
  cardiovascular system

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How the cardiovascular system responds to exercise

• Heart rate
• Stroke volume
• Cardiac output
• Blood flow
• Blood pressure
• Blood

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Heart Rate and Exercise

• Resting HR is 60-80 bpm in normal, healthy adults
• Elite endurance athletes can have a resting HR as
  low as 28-40 bpm
• Anticipatory response HR increases before
  exercise even starts (S. N. S.)
• Once exercise starts HR increases in direct
  relation of exercise intensity until max. HR is
  reached
• Max HR 220 - age

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Heart Rate and Exercise

• Steady-state HR when exercise intensity is
  constant the HR will level off
• Due to demands of tissues is met
• Cardiac drift HR increases after it levels off
  due to increase in body temperature

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Stroke Volume and Exercise

• Amount of blood ejected per beat
• Increases with exercise intensity proportionally
• Increases from 50-70 ml/beat at rest to 110-130
  ml/beat during exercises
• Will increase during exercise at the beginning
• Plateaus at a point and remains there until
  exhaustion

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Stroke Volume and Exercise

• Why does stroke volume increase with the onset of
  exercise?
• Left ventricle fills more completely
• Stretches further and the contraction to pump the
  blood out into the body is more forceful
• This is known as the FRANK-STARLING MECHANISM
• Increases until the you reach approx. 50 of your
  VO2 max

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Cardiac Output (Q) and Exercise

• Remember Q SV x HR
• It makes sense that during exercise Q will
  increase
• At rest Q 5L/min and can go up to 20-40L/min
  during exercise
• Your cardiac output at rest will not increase
  with exercise because as you increase your
  aerobic endurance your SV increases and your
  resting HR decreases!

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Blood Flow and exercise

• An increase in blood flow goes to the muscles
  during exercises
• For this to happen less blood goes to internal
  organs
• This is why you are told not to eat right before
  exercise (up to a few hours)

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Blood Pressure and Exercise

• Systolic blood pressure increases during
  exercise up to 200 mmHg
• WHY?
• Systolic blood pressure is the pressure during
  contraction of the heart
• Diastolic blood pressure remains fairly similar
  to rest as during exercise.

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Blood and exercise

• Blood plasma volume decreases with exercise
• Increase of hemoglobin concentration
• No increase in RBC just concentration
• Allows more oxygen to be carried in the blood
• You can use the amount of oxygen in arterial and
  venous blood to help figure out the oxygen
  consumption (VO2) used in exercise

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Developing a Cardiorespiratory Endurance Program

• Setting goals
• Applying the FITT equation
• Frequency
• Intensity
• Time
• Type of activity

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Frequency of Training

• Train 35 days per week
• Beginners should start with 3 and work up to 5
  days per week

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Intensity of Training

• Target heart rate zone
• Estimate your maximum heart rate (MHR)
• 220 your age MHR
• Multiply your MHR by 65 and 85
• People who are unfit should start at 55 of MHR
• Example 19-year-old
• MHR 220 19 201
• 65 training intensity 0.65 X 201 131 bpm
• 85 training intensity 0.85 X 201 171bpm

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Time (Duration) of Training

• Total of 2060 minutes is recommended
• One single session or multiple sessions of 10
  minutes or more
• Different intensity levels require different
  durations
• High-intensity activity 20 minutes
• Low-to-moderate-intensity activity 4560
  minutes

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Type of Training or Exercise

• What type of exercise or training will you do?
• Specificity refers to the specific PA chosen to
  improve a component of health related fitness
• CV/aerobic endurance training, plyometrics
  training, muscular endurance/strength training,
  sport specific training etc...

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Warming Up and Cooling Down

• Warming Up (510 minutes)
• Muscles work better when warmed up
• Redirect blood flow to working muscles
• Spread synovial fluid
• Cooling down (510 minutes)
• Blood flow and respiration return to normal

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Building Cardiorespiratory Fitness

• Rate of improvement depends on age, health
  status, initial level of fitness, and motivation
• Initial phase (14 weeks) 34 days per week, low
  end of target heart rate zone, 2030 minutes
• Improvement phase (26 months) 35 days per
  week, middle to upper end of target heart rate
  zone, 2540 minutes

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Maintaining Cardiorespiratory Fitness

• Continue to exercise at the same intensity on 3
  nonconsecutive days per week
• If you have to stop, start the program again at a
  lower level
• Cross-training maintains motivation

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Hot Weather and Heat Stress

• Dehydration excessive loss of fluid
• Heat cramps sudden development of muscle spasms
  and pain
• Heat exhaustion heat illness related to
  dehydration from exertion in hot weather
• Heat stroke a severe and often fatal heat
  illness characterized by significantly elevated
  core body temperature

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Preventing Heat Illness

• Use caution in high heat or humidity (over 80F
  and/or 60 humidity) lower your intensity and/or
  add rest breaks
• Exercise morning or evening
• Drink plenty of fluids check weight before and
  after exercise
• Avoid supplements and beverages containing
  stimulants
• Wear clothing that breaths
• Slow down or stop if you feel uncomfortable

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Heat Index
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Exercise in Cold Weather

• Hypothermia low body temperature due to
  exposure to cold conditions
• Frostbite freezing of body tissues
  characterized by pallor, numbness, and a loss of
  cold sensation
• Prevention
• Dont stay out in very cold temperatures (consult
  wind chill values)
• Wear appropriate clothing

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Wind Chill
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Final thoughts on CV and exercise

• Benefits to your cardiovascular system from
  endurance exercise
• Increase heart muscle in ventricles
• Decrease resting heart rate
• Increase resting stroke volume
• Better working capillaries and blood vessels
• Decrease blood pressure rate at rest