Exercise and altitude

Question 1

Do high speed movements benefit from high altitude?

Answer 1

Yes - The lower air density at altitude offers less resistance to high-speed
movement, and sprint performances are either not affected or are improved.

Question 2

Does endurance performance benefit from high altitude?

Answer 2

No - performance demands that is more dependent on O2 delivery to muscle

Question 3

What does Boyle’s Law tell us?

Answer 3

Gas volume inversely proportional to its pressure
e.g., at higher pressure, air starts to spread out (still same pressure of O2)

Question 4

What does hypoxia mean?

Answer 4

Low PO2

Question 5

What does normoxia mean?

Answer 5

Normal PO2

Question 6

What does hyperoxia mean?

Answer 6

High PO2

Question 7

What does hypoxaemia mean?

Answer 7

Low levels of blood O2

Question 8

What is the effect of altitude on environmental and physiological variables?

Answer 8

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 9

Short-term adjustments to altitude - ventilation changes?

Answer 9

• Hyperventilation (chemoreceptors)
• Raises alveolar O2
• Lowers alveolar CO2
• Causes alkalosis and diuresis (HCO3-)

Question 10

Short-term adjustments to altitude - CV changes?

Answer 10

Increased resting HR and Cardiac Output

Cold/dry air (reduced humidity), dehydration, UV light (sunstroke, blindness)

Question 11

What is the immediate physiological response to altitude ?

Answer 11

Get in more O2 molecules

Question 12

What happens to VO2max with increasing altitude?

Answer 12

Aerobic power is extremely reduced at high altitudes

Question 13

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

Answer 13

• Cardiac strain is reduced
  Lactate production also isn’t higher at altitude at max effort (lactate paradox)
• Max HR response to exercise is attenuated at altitude
• Evidence that activation of parasympathetic nervous system limits maximal heart rate response to exercise at altitude.

Question 14

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

Answer 14

Increased ventilation for same workload

Question 15

What is the difference in minute ventilation between acute and longer term response to altitude?

Answer 15

Minute ventilation increases more as a longer term response to altitude

Question 16

Altitude acclimatisation - why does CO fall if HR stays roughly the same?

Answer 16

Fick equation: VO2 = cardiac output x a-vO2 difference.

More O2 in the blood improves O2
extraction capacity = less reliance of
central delivery (i.e. less cardiac strain).

Question 17

What hormone typically increases O2 carrying capacity of blood cells?

Answer 17

EPO

Question 18

What effect does a decrease in plasma volume have?

Answer 18

Helps concentrate haemoglobin (Hb)

Question 19

In terms of a timeline, what order do events happen when spending time at altitude?

Answer 19

• Reduction in plasma volume occurs very quickly upon exposure to high altitude
• This increase O2 carrying capacity of blood by concentrating existing RBC
• This = increase Hematocrit
• Hypoxia stimulates synthesis + resynthesis of EPO from kidneys, which = true increase in RBC volume during more prolonged altitude acclimatization.

Question 20

Name some vascular/cellular changes to high altitude training?

Answer 20

• Increased capillarisation
• Increased myoglobin in muscles
• Increased aerobic enzymes (citrate synthase)
• However, muscle mitochondrial density probably does not increase
• a-vO2 difference during exercise, falls with short-term exposure, but widens following acclimatisation
• Increased lactate consumption and oxidation by active muscle

Question 20

What are the benefits of high altitude training?

Answer 20

Blood changes (red blood cell mass), some cellular changes, some circulatory changes.

Question 21

What are the detriments to high altitude training?

Answer 21

Blood changes (viscosity), cardiovascular changes, loss of training intensity (detraining effect?), reduced muscle mass, increased ventilatory response.

Question 22

What is the solution to the detriments high altitude training can cause?

Answer 22

Live high, train low? Tents (hypoxicators) believed by many to be an effective performance enhancer.

Question 23

What does the ‘live high, train low’ method involve?

Answer 23

Live at high altitude (may cause increase in RBC mass - via EPO).
- >22hr/day at 2000-2500m required
- Intermittent hypobaric hypoxia (3hr/day, 5 days/wk at 4-5k m)
- Train at low altitude (maintain high interval training velocity)

Question 24

What are things to consider when doing altitude training?

Answer 24

• Depends on individual (low vs high responder, individual differences may be due to training state before arriving at altitude)
• Pre-testing to determine likelihood of an effect?
• Think about what’s best for athlete (benefit or summer from camp?)