1. Cardiovascular System and Exercise

2. 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

3. 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

4. How the cardiovascular system responds to exercise
Heart rate
Stroke volume
Cardiac output
Blood flow
Blood pressure
Blood

5. Heart Rate and Exercise
Resting HR is bpm in normal, healthy adults
Elite endurance athletes can have a resting HR as low as 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= age

6. 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

7. Stroke Volume and Exercise
Amount of blood ejected per beat
Increases with exercise intensity proportionally
Increases from ml/beat at rest to ml/beat during exercises
Will increase during exercise at the beginning
Plateaus at a point and remains there until exhaustion

8. 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

9. 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!

10. 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)

11. 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.

12. 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

13. Developing a Cardiorespiratory Endurance Program
Setting goals
Applying the FITT equation
Frequency
Intensity
Time
Type of activity

15. Frequency of Training Train 3–5 days per week
Beginners should start with 3 and work up to 5 days per week

16. 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

17. Time (Duration) of Training
Total of 20–60 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 = 45–60 minutes

18. 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...

19. Warming Up and Cooling Down
Warming Up (5–10 minutes)
Muscles work better when warmed up
Redirect blood flow to working muscles
Spread synovial fluid
Cooling down (5–10 minutes)
Blood flow and respiration return to normal

20. Building Cardiorespiratory Fitness
Rate of improvement depends on age, health status, initial level of fitness, and motivation
Initial phase (1–4 weeks): 3–4 days per week, low end of target heart rate zone, 20–30 minutes
Improvement phase (2–6 months): 3–5 days per week, middle to upper end of target heart rate zone, 25–40 minutes

21. 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

22. 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

23. Preventing Heat Illness
Use caution in high heat or humidity (over 80°F 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

24. Heat Index

25. 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:
Don’t stay out in very cold temperatures (consult wind chill values)
Wear appropriate clothing

26. Wind Chill

27. 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