S2. Exercise at altitude

Question 1

What is a primary physiological limitation to exercise at high altitude?

Answer 1

VO2max is reduced due to hypoxia

Question 2

How does pulmonary artery pressure change at high altitude?

Answer 2

It increases due to hypoxic pulmonary vasoconstriction

Question 3

What is the impact of hypoxia on oxygen diffusion in the lungs?

Answer 3

It limits oxygen transfer due to reduced partial pressure gradients

Question 4

How does high altitude affect cardiac output during exercise?

Answer 4

Cardiac output is maintained but stroke volume may decrease

Question 5

What is the ‘Silver Hut’ expedition known for?

Answer 5

Studying human performance at extreme altitudes

Question 6

What is a chronic adaptation observed in high-altitude populations?

Answer 6

Increased hematocrit and capillary density

Question 7

What is the role of hypoxia-inducible factor (HIF) at high altitude?

Answer 7

It regulates gene expression for adaptation to hypoxia

Question 8

How does mitochondrial density change with prolonged high-altitude exposure?

Answer 8

Mitochondrial density decreases

Question 9

What is the ‘live high-train low’ approach?

Answer 9

Living at high altitude while training at lower altitudes to optimize performance

Question 10

How does iron infusion benefit exercise at high altitude?

Answer 10

It reduces pulmonary artery pressure and improves cardiopulmonary function

Question 11

What is the significance of bar-headed geese in altitude research?

Answer 11

They demonstrate superior oxygen transport and utilization in hypoxia

Question 12

What are common metabolic changes observed at high altitude?

Answer 12

Switch to glycolytic metabolism and increased UCP3 expression

Question 13

How does hypoxia affect pulmonary vascular remodeling?

Answer 13

It increases vascular resistance and pulmonary artery pressure

Question 14

What effect does chronic hypoxia have on the right ventricle?

Answer 14

Increased workload and potential hypertrophy

Question 15

How does high altitude impact VO2max?

Answer 15

VO2max decreases proportionally to the altitude level

Question 16

What adaptation reduces the risk of hypoxic pulmonary edema in high-altitude natives?

Answer 16

Blunted hypoxic pulmonary vasoconstriction

Question 17

How does acclimatization improve oxygen transport?

Answer 17

Increases red blood cell count and 2,3-DPG levels

Question 18

What is the impact of hypoxia on peripheral oxygen diffusion?

Answer 18

It reduces oxygen delivery to tissues due to lower oxygen gradients

Question 19

Why might athletes benefit from altitude training?

Answer 19

Improved oxygen delivery and erythropoiesis after returning to sea level

Question 20

What is the purpose of control groups in altitude training studies?

Answer 20

To assess the true effects of altitude exposure on performance

Question 21

How does prolonged hypoxia affect skeletal muscle?

Answer 21

Reduces oxidative capacity and shifts metabolism to glycolysis

Question 22

What is a limitation of ‘living high-training high’?

Answer 22

It can impair high-intensity training performance due to hypoxia

Question 23

How do chronic high-altitude populations differ genetically?

Answer 23

They have adaptations in HIF pathway genes for efficient oxygen use

Question 24

What is the role of UCP3 in high-altitude metabolism?

Answer 24

It regulates mitochondrial uncoupling and energy efficiency

Question 25

How does acute altitude exposure affect lactate production?

Answer 25

Increases due to a reliance on anaerobic metabolism

Question 26

What is the significance of 'Operation Everest II'?

Answer 26

A simulated study of human performance at extreme altitudes

Question 27

How does pulmonary vasodilation impact exercise at altitude?

Answer 27

Improves oxygenation but may increase blood flow inefficiency

Question 28

What is the effect of high altitude on blood oxygen saturation?

Answer 28

Decreased saturation due to reduced partial pressure of oxygen

Question 29

Why is iron status important for altitude adaptation?

Answer 29

Iron is essential for hemoglobin synthesis and oxygen transport

Question 30

What metabolic shift occurs in Phd1 knockout mice at altitude?

Answer 30

Improved adaptation to hypoxia with altered metabolism

Question 31

What is the impact of altitude training on erythropoiesis?

Answer 31

Stimulates red blood cell production through EPO activation

Question 32

What are the main ethical concerns with hypoxic training?

Answer 32

Potential unfair advantages and health risks

Question 33

How does the heart adapt acutely to altitude?

Answer 33

Increased heart rate to maintain cardiac output

Question 34

What is the effect of prolonged altitude exposure on muscle mass?

Answer 34

Muscle atrophy due to reduced protein synthesis

Question 35

What is the role of PPARa at high altitude?

Answer 35

Regulates lipid metabolism under hypoxic conditions

Question 36

How does exercise at altitude affect ventilation?

Answer 36

Ventilation increases to compensate for lower oxygen availability

Question 37

What is the significance of studying Chuvash polycythemia?

Answer 37

It provides insights into adaptations to chronic hypoxia

Question 38

Why is 'dose' of hypoxia important in training?

Answer 38

It determines the extent of physiological adaptations

Question 39

What is the relationship between high altitude and oxidative stress?

Answer 39

Increased oxidative stress due to hypoxia and reduced antioxidants

Question 40

How does high altitude affect capillary density?

Answer 40

Increases to enhance oxygen delivery to tissues