Week 8 - Exercise and Altitude

Question 1

What is altitude?

Answer 1

distance above sea level

Question 2

At high altitude, what happens to air density?

Answer 2

lower air density

Question 3

What is the effect of lower air density at altitude on high-speed movement and sprint performance?

Answer 3

offers less resistance to high-speed movement, and sprint performances are either not affected or improved

1964 Tokyo Olympics –> 1968 Mexico Olympics

Question 4

How does altitude influence short-term anaerobic performance?

Answer 4

• Lower air resistance may improve performance
• Lower PO2 at altitude should have no effect on performance (oxygen transport to muscle doesn’t limit performance)

Question 5

How does altitude influence long-term aerobic performance?

Answer 5

• Lower PO2 results in poorer aerobic performance as its dependent on oxygen delivery to the muscle.

Question 6

What is the relationship between atmospheric pressure and altitude?

Answer 6

Atmospheric pressure decreases at higher altitude

Question 7

Boyle’s law of - gas volume and pressure

Answer 7

gas volume inversely proportional to its pressure

Question 8

At high altitude we get the … percentages of O2, CO2, N2 in the air but we get a … partial pressure of O2, CO2, N2.

Answer 8

Same + Lower

Question 9

Why is the partial pressure of inspired oxygen (PO2) decreased at higher altitudes?

Answer 9

due to lower barometric pressure

Question 10

Hypoxia

Answer 10

low PO2 (low partial pressure of oxygen - occurs at high altitude)

Question 11

Normoxia

Answer 11

normal PO2 (sea level)

Question 12

Hyperoxia

Answer 12

High PO2

Question 13

Hypoxaemia

Answer 13

Low levels of oxygen in the blood

Question 14

Exposure to hypoxia results in a reduction in what? What does this disruption in homeostasis trigger?

Answer 14

Exposure to hypoxia directly results in a reduction in arterial oxygen pressure (PaO2). This disruption in homeostasis triggers neuroendocrine responses that help regulate important adjustments in key physiological systems.

Question 15

What is the time of useful consciousness at altitude?

Answer 15

60 seconds

Question 16

Identify the ventilatory and CV short-term adjustments to altitude.

Answer 16

Immediate response is to get in more O2 molecules!

Ventilation changes
* Hyperventilation (chemoreceptors)
* Raises alveolar O2
* Lowers alveolar CO2
* Causes alkalosis and diuresis (HCO3-)

Cardiovascular changes
* Increased resting heart rate and cardiac output

Question 17

What are the changes in V02max with increasing altitude?

Answer 17

As altitude increases, VO2max is reduced (less able to uptake oxygen and utilise it)

Question 18

What is the effect of altitude on the ventilatory response to sub-maximal exercise?

Answer 18

Increases ventilation at the same workload due to reduction in number of O2 molecules per litre of air, but Pao2 falls.

Question 19

What is the effect of acute exposure to altitude on the CV response to sub-maximal exercise?

Answer 19

HR and cardiac output increases during submaximal exercise as there is a lower oxygen content of arterial blood and increased SNA.

Question 20

What is the effect of high altitude on the HR response to maximal exercise?

Answer 20

Maximal HR response to exercise is attenuated at attitude due to the activation of the parasympathetic NS - act as cardioprotective?

Question 21

What is the short-term effect of altitude on a-vO2 difference?

Answer 21

decreased

Question 22

What happens to lactate production during maximal efforts at high altitude?

Answer 22

Lactate production isn’t higher at altitude during maximal effort (Lactate paradox)

Question 23

What is the beneficial effect of acclimatization?

Answer 23

Prolonged exposure to altitude increases oxygen uptake at sea level.

Question 24

Describe the CV long-term adjustments to altitude hypoxia.

Answer 24

– Heart rate increased (increased sympathetic
nerve activity)
– Stroke volume decreased
– Cardiac output unchanged or slightly decreased
– Maximal cardiac output decreased

Question 25

Describe the Vascular/cellular (local) long-term adjustments to altitude hypoxia.

Answer 25

– Increased skeletal muscle capillarization
– Increased RBC 2,3-DPG
– Increased myoglobin in the muscle
- Increased mitochondrial density
- greater a-vO2
– Increased oxidative enzyme activity
– Loss of body weight and lean body mass

Question 26

Explain the haemotologic (blood) long-term adjustments to altitude hypoxia.

Answer 26

– Decreased plasma volume
– Increased haematocrit, haemoglobin and RBC
number
- Increased Bohr shift

Question 27

Explain the pulmonary acid-base long-term adjustments to altitude hypoxia.

Answer 27

– Hyperventilation
– Excretion of base (HCO3-) via kidneys

Question 28

Purpose of high altitude training

Answer 28

perform better at sea level

Question 29

Benefits of high-altitude training

Answer 29

• Increased RBC mass
• Increased skeletal muscle capillarization
• Increased oxidative enzyme activity
• HR increased, SV decreased

Question 30

Detriments of high-altitude training

Answer 30

• Increased blood viscosity
• Loss of training intensity (detraining effect?)
• Reduced muscle mass
• Increased ventilatory response

Question 31

What is a solution to the detriments of high altitude training?

Answer 31

Live high, train low concept

e.g. tents (hypoxicators) believed to be an effective performance enhanced.

Question 32

Describe the “Live high, train low” concept.

Answer 32

• Live at high altitude may elicit an increased in RBC mass via EPO (erythropoietin - important hormone in making RBC) and this may lead to an increased V02max.
• Train at low altitude maintains high interval training velocity.

Question 33

Compared to the heart rate value measured at sea level, when a subject works at the same work rate (e.g., 150 watts) at 3,000 meters altitude, what happens to heart rate?

Answer 33

its higher