Altitude

Question 1

Larsen and Sheer (2015)

Answer 1

• > 50% of all time top 20 male performances from 800m -marathon come from Kenya
• Kelenjin tribe in Kenya - population of about 9mil, have won 40% of all medals from 800m - marathon at World Championships or Olympic level
• A town called Bekoji in Ethiopia - population of 17, 000 - accountable for 16 Olympic medals (10 golds) and 30 World Champions

Question 2

Altitude on Elite Performance: Tokyo vs Mexico

Answer 2

Tokyo (1964) - 44m above sea level
Mexico (1968) - 2240m above sea level

All events >1500m were ran faster in Tokyo
All events <800m were ran faster in Mexico

Question 3

Pugh et al (1971)

Answer 3

• 6-8% of the cost of distance running is to overcoming air resistance
• Therefore, shorter duration events were faster in Mexico due to less air resistance

Question 4

Field Events

Answer 4

Bob Bauman, 1968 Mexico olympics long jump

• Jumped 8.9m (WR)
• Broke previous WR by 80cm
• Thinner air contributed 7-30cm of performance improvement (Ward-Smith, 1980)

Question 5

O2 saturation - West and Wagor, (1980)

Answer 5

• After 0.25s, RBC is fully saturated with oxygen (sea level)
• At altitudes it takes longer for the RBC to becomes fully saturated
• As you ascend, the pressure driving the O2 into the RBC is reduced, so there is not enough time to complete saturation of RBC

Question 6

HR and Q Sub-maximal - Hultgren et al (1997)

Answer 6

• HR and Q increase with hypoxia (sub-maximally)
• However, it takes longer or RBC to fill with O2 at altitude
• Increasing HR reduces time for RBC to fill with O2, resulting in reduced O2 saturation
• Fall in vascular resistance due to aerials vasodilating to send blood to hypoxic areas

Question 7

O2 saturation - Wehrlin and Hallen (2006)

Answer 7

• SpO2 reduced with exercise at altitude
• As SpO2 reduced, so does VO2
• 62% of the variation in VO2 is explained by SpO2

Question 8

Max HR and Vo2 - Hultgren et al (1997)

Answer 8

• Max HR goes down at altitude, despite sub-max HR increasing
• Attainable VO2max is reduced
• HR goes down to protect any arrhythmia’s in the heart
• Every 1000m increase, we lose 1L of O2 per minute

Question 9

Why is increased Ve problematic?

Answer 9

• Carbon Dioxide (CO2) combines with Water (H2O) in the presence of Carbonic Anhydrase (CA) to form Carbonic Acid (H2CO3)
• Carbonic Acid is a weak acid and is disassociated into Hydrogen (H+) and Bicarbonate (HCO-3)
• Increased Ve at altitude blows off COs and therefore reduces H+, causing our blood to become more alkali

Respiratory alkalosis - We are excreting CO2 faster than metabolic production

Question 10

Blood plasma - Siebemann et al, (2017)

Answer 10

• After 24h exposure to high altitude blood plasma volume falls by 13% (0.5L of O2)
• Resulting in hypo hydration occurring very quickly

Question 11

What is Hypoxic Pulmonary Vasoconstriction?

Answer 11

• At sea level, all of our cardiac output goes through the lungs
• At altitude, we suffer vasoconstriction of the pulmonary circulation
• This is unique as all other vessels dilate at altitude

Question 12

Why does Hypoxic Pulmonary Vasoconstriction occur?

Answer 12

• Some alveoli becomes infected/diseased/dead and therefore we vasoconstrict to send blood to functioning alveoli
• However, at altitude the body can’t determine between these dead alveoli and reduced partial pressure of oxygen, meaning we get widespread pulmonary vasoconstriction

Question 13

Cognitive function - Taylor et al, (2016)

Answer 13

Stroop Test
- When above 14,000 ft, the Stroop score reduced (got worse)

Trail Making Test
- When above 16,000 ft, the time taken to complete the test was increased

Question 14

Cognitive function - Abriani et al (1998)

Answer 14

• 8 climbers simulated the ascent to Everest - 8848m in 31 days in a hypobaric chamber

Peg Board Test

• Control group saw a learning effect
• At simulated altitude saw initial learning effect before a decline in results

Visual Choice Reaction
- Time taken to complete the test was no different, however % of correct decisions made was

Question 15

Cognitive function - Aquino Lemos et al, (2012)

Answer 15

• 10 males in hypobaric chamber simulating 4,500m altitude vs CON
• Sleep quality was significantly reduced at altitude, with subjects never reaching a deep sleep

Question 16

Central fatigue - Amann et al (2007)

Answer 16

• 9 participants performed constant work to exhaustion at 21%, 15% and 10% FiO2
• At exhaustion, hypoxia was reversed to 30% FiO2

Results:

• Normoxia (21%) - 30% FiO2 had no sig effect
• Moderate hypoxia (15%) - Exhaustion occurred earlier than normoxia, 30% FiO2 has no sig difference
• Severe hypoxia (10%) - Exhaustion occurred earliest (<3min), but then 30% FiO2 had 171% performance improvement, to equivalent levels of hypoxia trial

Why?

• Perchera fatigue was not significantly impaired in severe compared to moderate hypoxia, meaning exhaustion occurred due to central fatigue
• Suggested that reduced cerebral oxidation at altitude was the reason for exercise termination

Question 17

Central fatigue - Goodall et al (2012)

Answer 17

• 9 trained cyclist completed 3 trials at 90% Wpeak
  1. Simulated acute hypoxia (3,800m)
  2. Same duration but normoxia (CON)
  3. TTE in anorexia
• Cerebral oxidation almost halved in the hypoxia trial
• Blood flow to the brain was reduced at hypoxia