Test 3: Chapter 24

Question 1

Atmospheric pressure

Answer 1

Decreases at higher altitude

Question 2

Partial pressure

Answer 2

Same percentages of O2, CO2, and N2 in the air

Lower partial pressure of O2, CO2, and N2

Question 3

Effect of Altitude on Performance

Answer 3

Short-term anaerobic performance
– Lower PO2 at altitude should have no effect on performance because O2 transport to muscle does not limit performance
– Lower air resistance may improve performance

Long-term aerobic performance
– Lower PO2 results in poorer aerobic performance dependent on oxygen delivery to muscle

Question 4

Jumping Through Thin Air (Bob Beamon)

Answer 4

Bob Beamon set new world record for
long jump in 1968 Olympic Games
– 29 feet 2.5 inches
– Lower air density at higher altitude

Question 5

Maximal Aerobic Power and Altitude

Answer 5

Decreased VO2 max at higher altitude
– Primarily due to lower oxygen extraction

Up to moderate altitudes (~4,000m)
– Decreased VO2 max due to decreased arterial PO2

At higher elevations
– VO2 max reduction also due to fall in maximum cardiac output. Decreased MAXIMAL heart rate at altitude

Question 6

Effect of Altitude on Submaximal Exercise

Answer 6

Elicits higher heart rate
– Due to lower oxygen content of arterial blood

Requires higher ventilation
– Due to reduction in number of O2 molecules per liter of air

Question 7

Acclimatization to High Altitude

Answer 7

Production of more red blood cells
– Higher hemoglobin concentration via HIF-1 and EPO. Counters desaturation caused by lower PO 2

Greater oxygen saturation
– Due to an increase in blood flow to the lungs. Results from increases in release of nitric oxide

Lifetime altitude residents
– Have complete adaptations in arterial O2 content and VO2 max
– Adaptations are less complete in those arriving at altitude later

Question 8

Hypoxia, erythropoietin, and red blood cell production process

Answer 8

Decreased blood O2

Kidneys increase EPO

EPO signals RBC production in red bone marrow

Increased blood O2

Question 9

Training for Competition at Altitude

Answer 9

Effect of training at altitude on VO2 max varies
widely among athletes
– Due to degree of saturation of hemoglobin

Some athletes can improve VO2 max by training at altitude, others cannot
– May be due to training state before arriving at altitude

Some athletes have higher VO2 max upon return to low altitude, while others do not
– Could be due to “detraining” effect. Cannot train as intensely at altitude

Question 10

Live High, Train Low (LHTL)

Answer 10

Live at high altitude
– Elicits an increase in red blood cell mass via EPO. Leads to increase in VO2 max
– ≥22 hr/day at 2,000–2,500 m required (or simulated altitude of 2,500–3,000 m for 12–16 hr/day)
– Intermittent hypobaric hypoxia. For example, 3 hr/day, 5 days/wk at 4,000–5,000 m

Train at low altitude
– Maintain high interval training velocity

Does LHTL increase performance at sea level?
– Does increase performance in some athletes but not all
– LHTL may impact elite athletes less than trained subjects

Question 11

Live High, Train Low, or the Reverse

Answer 11

Some studies have shown improved VO2 max
without increased RBC mass
– With intermittent hypoxia
– Potential mechanisms:
Improved mitochondrial function
Increased buffering capacity
– This is an area of active debate and research

Live low, train high
– Avoids negative effects of prolonged altitude exposure
– No real changes in VO2 max or hemoglobin
concentration

Question 12

The Lactate Paradox

Answer 12

Upon exposure to altitude
– Higher HR, ventilation, and lactate during exercise due to hypoxia.

After acclimatization
– Lactate response is reduced despite continued hypoxia

Causes of the lactate paradox
– Lower plasma epinephrine
– May also be due to muscle adaptations

Great debate about this topic
– Causes of the lactate paradox?
– Does it even exist? Some studies do not observe this phenomenon

Question 13

Factors Related to Heat Injury

Answer 13

Fitness
- Higher fitness related to lower risk of heat injury

Acclimatization

Question 14

Acclimatization to heat

Answer 14

Exercise in the heat for 10–14 days
- Low intensity, long duration (<50% VO 2 max, 60-100 min)
- Moderate intensity, short duration (75% VO 2 max, 30–35 min)

Adaptations
- Increases plasma volume and capacity to sweat
- Increases VO2 max, maximal cardiac output, LT, and performance
- Lower body temperature and HR response
- Reduces sodium loss in sweat

Best protection against heat stroke and exhaustion

Question 15

Air Pollution

Answer 15

Variety of gases and particulates

Has detrimental effect on health and performance
– Decreased capacity to transport oxygen
– Increased airway resistance
– Altered perception of effort

Physiological response depends on “dose”
– Concentration in air
– Duration of exposure
– Volume of air inhaled (Increases during exercise)

Question 16

Effect of Carbon Monoxide on VO2 Max

Answer 16

Binds to hemoglobin and reduces O2 transport

Affects sub max exercise and VO2 max