Altitude

Question 1

What is altitude?

Answer 1

The height of a object or point in relation to sea level.

Question 2

What are the classifications of altitude?

Answer 2

Low < 1250m
Moderate 1250-3000m
High 3000-6000m
Severe > 6000m

Question 3

What physical implications occur at the different classifications of altitudes?

Answer 3

Moderate - Altered exercise capability
High - Mountain sickness and well-being conditions
Severe - Clinical based problems may arise

Question 4

What is hypoxia?

Answer 4

Inadequate supply of oxygen to respiring tissue.

Question 5

What characteristic makes high altitude a hypoxic environment?

Answer 5

Lowered barometric pressure.

Question 6

What is Dalton’s law?

Answer 6

The total pressure exerted is equal to the sum of the partial pressure of the gasses.

Question 7

What is barometric pressure at sea level?

Answer 7

760mmHg

Question 8

How do you work out the partial pressure of a gas?

Answer 8

Fractional concentration x Total gas pressure

Question 9

What is hypobaric hypoxia?

Answer 9

Hypoxia as a result of low barometric pressure.

Question 10

What is normobaric hypoxia?

Answer 10

Hypoxia when barometric pressure is normal.

Question 11

What is the oxygen cascade?

Answer 11

A fall in partial pressure of Oxygen reduces the driving pressure for gas exchange in the lungs and in turn produces a cascade of effects to the level of the mitochondria.

Question 12

What is the impact of altitude of short distance races?

Answer 12

Short distance running times may be quicker at altitude due to the reduced barometric pressure meaning there is less air resistance.

Question 13

What is the impact of altitude on VO2 MAX?

Answer 13

There is a linear decrease in VO2 max performance with increasing altitude.

Question 14

What is the impact of altitude on maximal oxygen uptake?

Answer 14

Maximal oxygen uptake will decrease 1% for every 100m above 1500m.

Question 15

What comparisons can be made between hypobaric and normobaric hypoxia?

Answer 15

O2 saturation goes down in both conditions.
Minute ventilation slightly increases in both.
During moderate exercise minute ventilation was lower in HH compared with NH after 8 hours.
Increased sympathetic nervous system activity after exposure to altitude.

Question 16

What are the causes and symptoms of acute mountain sickness (AMS)?

Answer 16

Ascending faster than 500 m/d and exercising vigorously.

Headache, nausea, fatigue.

Question 17

What are the causes and symptoms of high altitude pulmonary oedema (HAPE)?

Answer 17

Ascending faster than 500 m/d and exercising vigorously.
Accumulation of fluid in the lungs that prevents the air spaces from opening and filling with air.
Breathlessness, fever, coughing frothy spit.
Develops after 2-3 days at altitude and can be fatal within hours.

Question 18

What are the causes and symptoms of high altitude cerebral oedema (HACE)?

Answer 18

Ascending faster than 500 m/d and exercising vigorously.
Severe headache, vomiting, confusion, drowsiness, coma.
Blood vessels damaged due to increased blood flow. May result in fluid leakage.

Question 19

What are the immediate responses to altitude?

Answer 19

Hyperventilation.
Increased blood flow during rest and sub-maximal exercise.
Increased resting systemic blood pressure.

Question 20

What are the long term responses to altitude?

Answer 20

Increased blood O2 carrying capacity (not long term adaptation and will reverse if you return to lower altitude).
This is due to EPO synthesis which increases Hb synthesis and RBC concentration.

Question 21

How long does it take to adapt to altitude?

Answer 21

It takes two weeks to adapt to altitudes up to 2300m. Above that 1 week for every 610m.