Exercise physiology 2

Question 1

The heart is regulated by…

Answer 1

by the heart itself (pacemaker cells) and the CNS

Question 2

Max heart rate is not affected by endurance training
true/false

Answer 2

true

Question 3

Max heart rate declines with…

Answer 3

Max heart rate declines with ageing
(altered sensitivity for sympathetic stimulation)

Question 4

What three factors determine stoke volume?

Answer 4

• Venous return (more blood returning = increase stroke volume)
• Sympathetic nervous system
• Arterial pressure counteracts the effect (higher during exercise)

During exercise, net stroke volume increases

Question 5

Cardiac output is ? and it is increased during exercise

Answer 5

heart rate *stroke volume (l/min)

Question 6

In endurance trained athletes, the resting parasympathetic activity A, sympathetic activity B, heart rate C.

Diastolic volume D, systolic volume E, stroke volume F

Answer 6

A increases
B decreases
C decreases
D increases
E decreases
F increases

Question 7

Sedentary vs athletes: difference in resting heart rate, resting stroke volume, resting cardiac output (l/min)?

Answer 7

1. heart rate increase sedentary
2. resting stroke volume decrease sedentary
3. resting cardiac output the same

Question 8

Maximal heart rate does/does not increase by training

Answer 8

does not

Question 9

Cardiac output in athletes: is it increased during exercise vs students? Why/why not?

Answer 9

Yes, it is caused by the increased stroke volume

Question 10

Cardiovascular drift: this happens during exercise >15 min. What happens with stroke volume, heart rate, CBF (cutaneous blood flow), venous return?

Answer 10

Stroke volume down
Heart rate up
CBF (blood flow to skin) up
venous return down

Question 11

An untrained and trained subject perform aerobic exercise at exactly the same level. Who has the highest O2 consumption and cardiac output?

Answer 11

No large differences.

Same level exercise: you need roughly the same amount of energy, same cardiac output, same O2 consumption. However, the athlete has a lower heart rate.

Question 12

An untrained and trained subject perform aerobic exercise at their maximum level. Who has the highest O2 consumption and cardiac output?

Answer 12

Trained athlete.

Now the situation is not comparable. Trained subject has higher performance. More energy needed.

Question 13

cardiac functioning important determinant of aerobic performance: yes or no

Answer 13

yes. VO2 max related to max cardiac output

Question 14

Cardiac output increases to a lesser extent than O2 consumption. How is this extra O2 delivered? What may explain the disrepancy between cardiac output (max increase 8x) and O2 consumption (max increase 23x)?

Answer 14

Increased O2 extraction by exercising tissues + selective blood flow to exercising tissues

Question 15

VO2 max increases by training: cardiac output and O2 extraction. What is the small effect and what is the main effect?

Answer 15

Small effect of training on extraction of oxygen, main effect on cardiac output.

Question 16

Static exercise, heavy load:

• increase in X blood pressure (stroke volume)
• increase in X blood pressure

Muscle contraction >60% of max force occludes muscle blood flow and results in high vascular resistance

Answer 16

Systolic,
diastolic

Question 17

Dynamix exercise, increasing intensity:
Increase in X blood pressure (stroke volume)
Little effect/small decrease in X blood pressure
Why?

Answer 17

Systolic
Diastolic

Alternating contractions and relaxations facilitate muscle blood flow -> lower vascular resistance

Question 18

Consider the effects of vascular resistance on blood pressure. Is there a difference in blood pressure responses between arm and leg exercises (at similar level of effort: same % VO2 max)

Answer 18

Yes, higher increase in arm exercise:

Smaller muscle mass and vasculature in arms results in greater resistance to blood flow. Blood that flows through the arm to deliver the same amount of oxygen experiences much more resistance: same amount of blood is required for this VO2 max.

Question 19

Regulation of blood flow:  Blood flow is devided amongst different organs during rest. During exercise, much more blood goes to the muscles. What is important to keep in mind?

Answer 19

This is relative, because there is much more blood to devide

Question 20

How does the dilation and vasoconstriction work in the arteries? How is this determined?

Answer 20

Metabolism up
O2 down
CO2 up
vasodilation
resistance down
blood flow up

Vice versa with constriction

Question 21

What are extrinsic factors for vasodilation/constriction?

Answer 21

• sympathetic nervous system: vasoconstriction
• epinephrine: constriction or dilation (dilation to heart and muscle)
• NO parasympathetic innervation of vascular smooth muscle cells
• NO: vasodilation

Question 22

Where does NO come from?

Answer 22

synthesized from arginine
- Vascular endothelium contains endothelial NO synthase

Question 23

The more nitrite, the more flow-mediated dilation, more maximal power

• Several studies show positive effects of NO donors on performance
• Other studies show no effect (especially in well-trained subjects)

Answer 23

Ok

Question 24

Summary: to meet the increased demand of oxygen during aerobic exercise, these processes are all upregulated:

Answer 24

Pulmonary ventilation up
Cardiac output up (heart rate and stroke volume up)
Unloading oxygen from haemoglobin up

Question 25

Training increases aerobic performance:

What are the effects on the following factors?

1. pulmonary ventilation
2. cardiac output
3. stroke volume
4. blood flow to skeletal muscles
5. capillarization
6. unloading of oxygen from haemoglobin
7. oxidative capacity of muscle fibers
   (mito biogenesis, mito enzyme activity)
8. exercise-induced restriction of blood flow to splanchnic organs

Answer 25

1. no effect
2. increase
3. increase
4. increase
5. increase
6. small effect
7. increase (increase, increase)
8. decrease

Question 26

Now, recall on what things training on aerobic performance has an effect

Answer 26

BUCC
POES

1. blood flow to skeletal muscles
2. unloading of oxygen from haemoglobin
3. capillarization
4. cardiac output
5. pulmonary ventilation
6. oxidative capacity of muscle fibers
   (mito biogenesis, mito enzyme activity)
7. exercise-induced restriction of blood flow to splanchnic organs
8. stroke volume