Altitude

Question 1

In 1978 what was the estimated VO2 max on Everest thought to be and why?

Answer 1

15 ml/kg/min due to miscalculation of barometric pressure at the Everest summit.

Question 2

Why do successful climbers have a better capacity for hyperventilation?

Answer 2

To drive down PCO2 and H+ in the blood allowing for more O2 to bind with hemoglobin at the same PO2

Question 3

What are the effects of climbers having to contend with loss of appetite?

Answer 3

Weight loss and reduction of both type 1 and 2 muscle fiber diameter

Question 4

What happens to the percentage of oxygen in the air as altitude increases?

Answer 4

The % of O2 in the air does not change

Question 5

What happens to the partial pressure of oxygen in the air as altitude increases

Answer 5

The partial pressure of oxygen decreases as altitude increases

Question 6

What happens to barometric pressure as altitude increases?

Answer 6

Barometric pressure decreases

Question 7

What happens to the diffusion gradient in the tissues at altitude?

Answer 7

Diffusion gradient at the tissues is much lower making it harder for the muscle to receive oxygen as quickly

Question 8

What effect does altitude have on the hemoglobin oxygen dissociation curve?

Answer 8

Low PO2 Hypoxia causes shift to the left; Easier unloading

Question 9

What three components make up arterial oxygen content

Answer 9

1. Saturation
2. Hemoglobin concentration
3. Partial pressure of Oxygen in the arteries

Question 10

What happens to VO2 max at higher altitudes?

Answer 10

Decrease in VO2 max

Question 11

Higher altitude changes to oxygen

Answer 11

Lower partial pressure of oxygen in air means less oxygen in the alveoli, less oxygen in the arteries, carrying less oxygen and ultimately less oxygen being delivered to the muscles

Question 12

Why do trained individuals have a larger decline in % VO2 max

Answer 12

At altitude there is a lower partial pressure of oxygen in the alveoli but trained individuals have a higher stroke volume and shorter Pulmonary capillary transit time so they will have less oxygen sent to the tissues

Question 13

What can protect VO2 max decline

Answer 13

Higher Hb-O2 affinity

Question 14

What is the Intrapulmonary arteriovenous anastomoses

Answer 14

Blood is redirected through this shunt and blood wont be oxygenated but the pressure is decreased

Question 15

Patent foramen ovale

Answer 15

Foramen ovale remains open after birth when it is supposed to close

Question 16

Risks of having PFO at altitude

Answer 16

More at risk for venous blood to pass to the atrium and bypassing the lungs

Question 17

What happens to heart rate during submaximal exercise at altitude

Answer 17

Heart rate increases due to lower PO2 triggering increases in epinephrine causing vasodilation in the peripheries and vasoconstriction in the lungs

Question 18

What happens to ventilation at submaximal exercise in altitude

Answer 18

Ventilation increases as peripheral chemoreceptors sense lower PO2

Question 19

How does altitude affect short term anaerobic performance?

Answer 19

Lower PO2 at altitude doesn’t effect performance because O2 transport to the muscles does not limit performance in these events (non-oxidative sources)

Question 20

What is the benefit of short-term anaerobic performance at altitude?

Answer 20

Lower air resistance may improve performance

Question 21

Altitude impact on long-term aerobic performance

Answer 21

Lower PO2 decreases performance as muscles are dependent on oxygen being delivered to function

Question 22

What happens to plasma volume upon initial arrival to altitude?

Answer 22

There is a decrease in SV leading to a decrease in plasma volume due to respiratory water loss and increased urine production; leads to increased hematocrit

Question 23

What happens to plasma volume after a few weeks at altitude?

Answer 23

Plasma volume will return to normal if adequate fluid is ingested.

Question 24

What three things happen to acclimatize to high altitude?

Answer 24

1. Production of more red blood cells
2. Greater oxygen saturation
3. Hyperventilation

Question 25

How do you produce more red blood cells during acclimatize to high altitude

Answer 25

Stimulus of the decrease of partial pressure of oxygen causes kidneys to release EPO hormone which increases rbc production

Question 26

Why is there greater oxygen saturation during acclimatize to high altitude

Answer 26

There is an increase in the blood flow to the lungs caused by higher nitric oxide levels which dilates blood vessels

Question 27

Lifetime altitude residents experience what changes

Answer 27

Adaptations in arterial O2 content and VO2 max

Question 28

Why does hyperventilation occur during acclimatization to high altitude?

Answer 28

There is an increased sensitivity of the carotid chemoreceptor

Question 29

What are the negative consequences of carotid chemoreceptors sensitization causing Hyperventilation

Answer 29

Increased shortness of breath; fatigue respiratory muscles; blood is redistributed to the lungs and taken away from the muscles; hypertension long term

Question 30

Three main consequences of carotid chemoreceptor sensitization

Answer 30

1. Hyperventilation
2. Sleep disruption
3. Reduction in plasma volume

Question 31

What can athletes who normally train at altitude most effectively prepare for competition at altitude?

Answer 31

1. Compete within 24 hours upon arrival to altitude
2. Breathe hypoxic gases 1-2 hrs per day 3-5 days before
3. Train at altitude for a minimum of 2 weeks before competing

Question 32

Benefit of living at higher altitudes

Answer 32

Increases rbc mass via epo which increases VO2 max.

Question 33

Benefit of low altitude training

Answer 33

Maintain high interval training velocity; hemoglobin desaturation

Question 34

Why could sea level performance not improve after training with altitude exposure

Answer 34

If you have bad responses to altitude and it makes you more untrained; Or detraining effect from not being able to train as intensely at altitude

Question 35

Living low training high effect

Answer 35

Avoids negative effects of prolonged altitude exposure; no cereal changes in VO2 Mac or hemoglobin concentration