Chapter 2 - Exercise Physiology

Question 0

What is the contractile force of the heart called and how is it calculated?

Answer 0

• Called the ejection fraction.
• It is the percentage of the end diastolic volume that is ejected with each contraction of the heart.
• Normally 50-60% at rest and 60-80% during exercise.

Question 1

What is Q•?
How does it change during exercise?
How do you calculate Q•?

Answer 1

Q• is cardiac output, which averages 1.3 gallons/min.
- During maximal exercise it increases to ~5-6.5 gallons.
Q• = HR x SV
- HR increases linearly, SV goes to 49-50% capacity then plateaus.

Question 2

What is tissue that receives too little blood flow to restore ATP aerobically?
What is the condition called and what happens during exercise?

Answer 2

It is ischemic tissue, and people who have ischemia have inadequate blood flow to the heart because if narrowed coronary arteries. Their ejection fraction may be normal at rest but decrease with exercise.
* It’s like having your heart fall asleep instead of your arm.