Environmental effects on the body

Question 1

What happens to environmental conditions as height above sea level increases?

Answer 1

As height increases barometric pressure decreases and so does PO2

Question 2

At sea level what is the PO2 and the diffusion gradient?

Answer 2

PO2 = 159mmHg
Diffusion gradient = 119

Question 3

At 3600m above sea level what is the PO2 and the diffusion gradient?

Answer 3

PO2 = 105mmHg
Diffusion gradient = 65

Question 4

At 8800m above sea level what is the PO2 and the diffusion gradient?

Answer 4

PO2 = 43mmHg
Diffusion gradient = 3

Question 5

What is the overall effect of an athlete competing at high altitude?

Answer 5

O2 diffusion decreases reducing haemoglobin saturation resulting in poor O2 transport

Question 6

What are the consequences of decreased haemoglobin saturation?

Answer 6

• reduced blood plasma volume increasing RBC density
• SV decreases increasing HR
• max CV, SV and HR decreases during maximal intensity exercise

this reduces aerobic capacity and VO2 max

Question 7

How long does it take to acclimatise to 1000-2000m above sea level?

Answer 7

3-5 days

Question 8

How long does it take to acclimatise to 2000-3000m above sea level?

Answer 8

1-2 weeks

Question 9

How long does it take to acclimatise to 3000-5000m above sea level?

Answer 9

2+ weeks

Question 10

How long does it take to acclimatise to 5000-5500m above sea level?

Answer 10

4+ weeks

Question 11

What are the benefits of acclimatisation?

Answer 11

• increased RBC production du to increased erythropoietin release
• BR stabilises although is more elevated than at rest
• SV + CO reduce as O2 extraction becomes more efficient
• reduced incidents of altitude sickness

Question 12

What is cardiovascular drift?

Answer 12

upward HR drift associated with rise in body temperature

Question 13

What are the implications on the cardiovascular system of arteriole and capillary dilation near the skin surface?

Answer 13

increased blood flow and blood pooling of limbs

Question 14

What are the implications on the cardiovascular system of decreased SV, CO, BP, blood volume and venous return?

Answer 14

• increased HR to compensate
• increased strain on CV system
• reduced O2 transport to muscles

Question 15

What are the implications on the respiratory system of dehydration and airway drying?

Answer 15

• increased mucous production
• airway constriction
• decreased air volume for gaseous exchange

Question 16

What are the implications on the respiratory system of increased BR to maintain O2?

Answer 16

Increased O2 for exercise

Question 17

How can performance in heat be maximised pre competition?

Answer 17

• 7-14 days acclimatisation to increase body’s heat tolerance
• cooling aids reduce core temp delaying dehydration

Question 18

How can performance in heat be maximised during competition?

Answer 18

• pacing strategies
• suitable clothing to maximise heat loss
• rehydration with hypotonic/isotonic solution

Question 19

How can performance in heat be maximised post competition?

Answer 19

• cooling aids e.g fan
• rehydration using isotonic/ isometric solution to replace lost fluids, glucose and electrolytes