Exercise and Altitude W8

Question 1

What are the long-term effects of altitude on aerobic performance?

Answer 1

Lower PO2 results in poorer aerobic performance
(dependent on oxygen delivery to muscle)

Question 2

What are the short-term effects of altitude on anaerobic performance?

Answer 2

Lower air resistance may improve performance
Lower PO2 at altitude should have no effect of performance

Question 3

What happens to atmospheric pressure at higher altitude?

Answer 3

It decreases

Question 4

What is Boyle’s Law?

Answer 4

Gas volume inversely proportional to it’s pressure

Question 5

What is altitude?

Answer 5

Lower air density at higher altitude (air pressure)

Question 6

What is hypoxia?

Answer 6

Low PO2 (altitude)

Question 7

What is normoxia?

Answer 7

Normal PO2 (sea level)

Question 8

What is hyperoxia?

Answer 8

High PO2

Question 9

What is hypoxaemia?

Answer 9

Low levels of oxygen in the blood

Question 10

What are the short-term ventilation changes to altitude?

Answer 10

Hyperventilation (chemoreceptors)
Raises alveolar O2
Lowers alveolar CO2
Alkalosis

Question 11

What are the short-term cardiovascular changes to altitude?

Answer 11

Increased resting heart rate and cardiac output

Question 12

What are the physiological responses to exercise after being at high altitude?

Answer 12

Reduced partial pressure of O2
Reduced VO2max
Reduced maximal heart rate
Reduced a-VO2 difference

Increased heart rate and cardiac output
Increased ventilation

Question 13

How is VO2max calculated?

Answer 13

FICK’S EQUATION

VO2=CO x a-VO2 difference

Question 14

Why does ventilation increase during altitude exercise?

Answer 14

Due to reduction in number of O2 molecules per litre of air while PaO2 falls

Question 15

Why does heart rate and cardiac output get higher during sub-maximal workloads at altitude?

Answer 15

Due to lower oxygen content of arterial blood

Question 16

Why does maximal heart rate become lower after altitude exposure?

Answer 16

Due to parasympathetic (vagal) activation

Question 17

What are the blood changes to altitude?

Answer 17

Polycythaemia
Decreased plasma volume

Question 18

What is polycythaemia?

Answer 18

Increased production of red blood cells

Question 19

Why does red blood cell volume increase at altitude?

Answer 19

Hypoxia stimulates the synthesis and resynthesis of erythropoietin (EPO)

Question 20

What are the vascular/cellular changes to altitude?

Answer 20

Increased capillarisation
Increased myoglobin in muscles
Increased aerobic enzymes
Increase lactate consumption and oxidation by active muscles

Question 21

What are the long-term pulmonary acid-base adjustments to hypoxia?

Answer 21

Hyperventilation
Excretion of base (HCO3) via kidneys

Question 22

What are the long-term cardiovascular adjustments to hypoxia?

Answer 22

Heart rate increased
Stroke volume decreased
Cardiac output unchanged or slightly decreased
Maximal cardiac output decreased

Question 23

What are the long-term haematologic adjustments to hypoxia?

Answer 23

Decreased plasma volume
Increased:
- Haematocrit
- Haemoglobin
- Red Blood Cell number

Question 24

What are the long-term localised adjustments to hypoxia?

Answer 24

Increased skeletal muscle capillarization
Increased RBC 2,3-DPG
Increased oxidative enzyme activity
Loss of body weight and lean body mass

Question 25

What are the detriments of high altitude training?

Answer 25

Blood changes (viscosity)
Cardiovascular changes
Loss of training intensity (detraining)
Reduced muscle mass
Increased ventilatory response