W30-L6: Exercise oxygen, heat and fluids

Question 1

What is O2 uptake dependent on?

Answer 1

Intensity of exercise

Question 2

How can you measure the amount of O2 being used?

Answer 2

difference between o2 inhaled and o2 exhaled

Question 3

What is max O2 uptake?

Answer 3

where an increase

in power no longer increases o2 uptake

Question 4

What is the distribution of cardiac output during exercise?

Answer 4

vasoconstrict some areas such as splanchnic and renal, coronary increases
muscle blood flow increases, up to 90% at maximal

Question 5

What happens at very high intensity exercise to blood flow?

Answer 5

muscles can vasoconstrict to maintain cerebral perfusion, skin can vasoconstrict (more important than dilation for losing heat)

Question 6

What is the cause of exercise hyperaemia?

Answer 6

• Local signals (metabolic vasodilators)

- Blunted sympathetic activity to vessels

Question 7

What is the cardiac response to exercise?

Answer 7

Increased CO, lower HR (but greater SV), increased BP (decreased diastolic due to TPR loss but overall larger systolic increase)

Question 8

What is cardiovascular drift?

Answer 8

increase in heart rate thought due to be following the decrease in stroke volume, hyperthermia, dehydration

Question 9

What are the causes of increased CO following training?

Answer 9

• Expanded blood vol.
• Increased Heart size
• Increased adrenergic sensitivity

Question 10

What are the microvascular adaptions to exercise training?

Answer 10

Increased capillary density and recruitment which means blood is better able to be distributed to the muscle

Question 11

How does ventilation change during exercise?

Answer 11

early on ventilation tracks with VO2, later ventilation increases relative to VO2 (Pa O2 goes up, Pa CO2 goes down)

Question 12

What are the causes of exercise hyperpnea?

Answer 12

-Motor cortical activation
-CO2 flux to the lung
-Increased H+, lactate
No role for O2

Question 13

What are limitations for Vo2 max?

Answer 13

Primarily determined by oxygen delivery not uptake

Question 14

What does a low VO2 mean?

Answer 14

issue with lungs, heart and peripheral circulation (in terms of delivering o2 not using it)

Question 15

What is VO2 max closely correlated with?

Answer 15

systemic O2 delivery

Question 16

What are the mechanisms of heat loss during exercise?

Answer 16

• Sweat (more important as environmental temp increases)
• Convection
• Conduction

Question 17

What is the cardiovascular response to exercise in heat?

Answer 17

Have to transfer heat from muscle to the skin so systemic vasodilation to the skin due to increased temperature

Question 18

What effect does heat stress have on exercise capacity?

Answer 18

Impairs it as brain can regulate temp by decreasing max power output to prevent heating in a hotter environment

Question 19

How does the body restore blood volume after exercise?

Answer 19

for some time
after exercise
you get an increase
in aldosterone and
renin which increases
Na and H20 retention

Question 20

How does Na levels effect return to normal blood levels after exercise?

Answer 20

the higher the Na

the better you are at returning normal blood volume