Exercise and altitude Flashcards

1
Q

Do high speed movements benefit from high altitude?

A

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

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2
Q

Does endurance performance benefit from high altitude?

A

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

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3
Q

What does Boyle’s Law tell us?

A

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

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4
Q

What does hypoxia mean?

A

Low PO2

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5
Q

What does normoxia mean?

A

Normal PO2

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6
Q

What does hyperoxia mean?

A

High PO2

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7
Q

What does hypoxaemia mean?

A

Low levels of blood O2

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8
Q

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

A

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

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9
Q

Short-term adjustments to altitude - ventilation changes?

A
  • Hyperventilation (chemoreceptors)
  • Raises alveolar O2
  • Lowers alveolar CO2
  • Causes alkalosis and diuresis (HCO3-)
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10
Q

Short-term adjustments to altitude - CV changes?

A

Increased resting HR and Cardiac Output

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

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11
Q

What is the immediate physiological response to altitude ?

A

Get in more O2 molecules

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12
Q

What happens to VO2max with increasing altitude?

A

Aerobic power is extremely reduced at high altitudes

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13
Q

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

A
  • 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.
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14
Q

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

A

Increased ventilation for same workload

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15
Q

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

A

Minute ventilation increases more as a longer term response to altitude

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16
Q

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

A

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).

17
Q

What hormone typically increases O2 carrying capacity of blood cells?

A

EPO

18
Q

What effect does a decrease in plasma volume have?

A

Helps concentrate haemoglobin (Hb)

19
Q

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

A
  • 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.
20
Q

Name some vascular/cellular changes to high altitude training?

A
  • 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
20
Q

What are the benefits of high altitude training?

A

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

21
Q

What are the detriments to high altitude training?

A
  • blood changes (viscosity)
  • CV changes
  • Loss of training intensity (detraining)
  • Reduced muscle mass
  • Increased ventilatory response
22
Q

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

A

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

23
Q

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

A

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)

24
Q

What are things to consider when doing altitude training?

A
  • 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?)