Week 8 - Exercise and altitude

Question 1

Whats Boyles Law

Answer 1

Gas volume is inversely proportional to its pressure

Question 2

What is the impact on barometric pressure and altitude

Answer 2

Same percentages of o2, co2 and n2 in the air.
Lower partial pressure of o2, co2 and n2

Question 3

Whats hypoxia

Answer 3

Low PO2 (altitude)

Question 4

Whats Normoxia

Answer 4

Normal PO2 (sea level)

Question 5

Whats Hyperoxia

Answer 5

High PO2

Question 6

Whats hypoxemia

Answer 6

Low levels of oxygen in the blood

Question 7

Whats the impact of exposure to hypoxia

Answer 7

Results in a reduction of arterial oxygen pressure (Pao2). This disruption in homeostasis triggers neuroendocrine responses that help regulate important adjustments in key physiological systems

Question 8

Explain the oxygen transport cascade

Answer 8

Ambient air -> lungs -> hemoglobin-> cardiac output ->muscle blood flow -> oxygen extraction -> cellular metabolism

Question 9

Whats an immediate response to altitude

Answer 9

More o2 molecules recruited

Question 10

What are the ventilation changes to altitude

Answer 10

Hyperventilation (chemoreceptors)
Raises alveolar o2
Lowers alveolar co2
causes alkalosis and diuresis (HCO3)

Question 11

What are the cardiovascular changes to altitude

Answer 11

Increased resting heart rate and cardiac output

Question 12

What are some other effects of being at altitude

Answer 12

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

Question 13

Whats the effect of altitude on the ventilatory response to sub maximal exercise

Answer 13

Increased ventilation for same workload

Question 14

Whats the effect of acute exposure to altitude on the cardiovascular response to sub maximal exercise

Answer 14

Heart rate increased during submaximal exercise - lower oxygen content and increased SNA

Question 15

Whats the effect of high altitude on the heart response to maximal exercise

Answer 15

At max cardiac strain is reduced.
Lactate production is also isnt higher at altitude at maximal intensity
Maximal heart rate response to exercise is attenuated at altitude
Evidence that activation of PNS limits maximal heart rate response to exercise at altitude
Parasympathetic blockade (glycopyrrolate) restores maximal heart rate response to exercise (closed triangles)

Question 16

Whats the effect of altitude acclimatisation on the cardiovasucular response to sub maximal response

Answer 16

More o2 in the blood improves o2 extraction capacity = less reliance of central delivery

Question 17

What are the blood changes due to high altitude
(ON SHEET)

Answer 17

Polycythemia due to increased erythoprotein (EPO)
Decreased plasma volume
Hyperventilation causes alkalosis which shifts the oxyhaemoglobin disocciation curve to the left, but increase in 2,3 diphosphoglycerate in RBC’s shifts ODC ro right and causes increased Bohr shift

Question 18

What are the vascular / cellular changes to high altitude

Answer 18

increased capilarization - largely due to reduction in muscle mass
Increased myoglobin in muscles
Increased aerobic enzymes (citrate synthase)
However muscle mitochindrial density does not increase
A-VO2 difference during exercise, falls with short-term exposure but widens following acclimatisation
Increased lactate accumulation and oxidation by active muscle

Question 19

What are the benefits to high altitude training

Answer 19

Blood changes (red cells mass) some ceullular changes, some circulatory changes

Question 20

What are the detriments to altitude training

Answer 20

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

Question 21

Whats a solution to the detriments of altitude training

Answer 21

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

Question 22

Whats the effect of live high train low

Answer 22

May elicit an increase in red blood cell mass via EPO leads to increases VO2 max
>22hr/day at 2,000-2,500m required or stimulated altitude of 2,500-3,000m for 12-16hr/day
Intermittent hypobaric hypoxia. E.g 3hr/day, 5 days/wk at 4,000-5,000m
Train at low altitude. Maintain high interval velocity