Environmental Effects on Body (A2)

Question 1

Define barometric pressure:

Answer 1

The pressure exerted by Earth’s atmosphere at any given point

Question 2

What happens to barometric pressure as altitude increases?

Answer 2

Barometric pressure decreases -> pO2 decreases

Question 3

pO2 at sea level (outside body vs in capillary blood)

Answer 3

159 mmHg vs 40 mmHg

Question 4

pO2 3600m above sea level (outside body vs in capillary blood) and significance of 3600m

Answer 4

105 mmHg vs 65 mmHg (45% reduction)

3600m = SA FIFA World Cup

Question 5

pO2 8800m above sea level (outside body vs in capillary blood) and significance of 8800m

Answer 5

43 mmHg vs 3 mmHg

8800m = Mt Everest

Question 6

What does decrease in pO2 mean for haemoglobin’s affinity for oxygen and % saturation?

Answer 6

Affinity decreases as it can’t pick up O2 at the lungs

Reduction in % saturation

Question 7

Side effects (5) of low haemoglobin saturation:

Answer 7

Increase in breathing rate
Blood volume decrease (blood plasma drops by 25% to allow for inc in RBC)
Haematocrit (ratio between RBC and blood volume) levels rise
SV decrease (caused by low blood volume) -> HR inc to counter this
VO2 max dec at max intensity (every 1000m above 1500m, VO2 dec by 8-11%

Question 8

Main (2) side effects of low haemoglobin saturation:

Answer 8

Reduction in aerobic capacity and VO2 max

Question 9

Define acclimatisation:

Answer 9

Process of gradual adaption to change in environment

Question 10

What are the general guidelines for acclimatisation at (1000-2000, 2000-3000, 3000+, 5000+)?

Answer 10

1000-2000: 3-5 days
2000-3000: 1-2 weeks
3000+: 2+ weeks
5000+: 4+ weeks

Question 11

Benefits (4) of acclimatisation:

Answer 11

Increased erythropoietin (hormone produces RBC) leads to increase in RBC
Breathing rate and ventilation stabilised
Lower SV and Q (oxygen extraction becomes more efficient)
Reduced altitude sickness/headaches/breathlessness

Question 12

Thermoregulation definition:

Answer 12

The process of maintaining internal core body temperature (37 degrees)

Question 13

Role of thermoreceptors:

Answer 13

Sense change in body temp

Increase in temp leads to heat moved to skin surface and lost via evaporation and convection

Question 14

Hyperthermia vs Hypothermia

Answer 14

Hyper: Significantly raised core body temp
Hypo: Significantly lowered core body temp

Question 15

Causes of hyperthermia:

Answer 15

High and prolonged exercise intensity
High air temperature
High relative humidity

Question 16

Cardiovascular drift definition:

Answer 16

Upward drift in HR associated with high core body temp (1 degree inc can inc HR by 10 bpm)

Question 17

Effects of heat and humidity exercise on cardiovascular system (2):

Answer 17

Blood vessel dilation to skin

Dec blood volume, VR, SV, Q, BP (dehydration)

Question 18

Effects of heat and humidity exercise on respiratory system (3):

Answer 18

Dehydration and airways drying (32 degrees)
Increased breathing frequency
High sunlight -> more pollutants in air

Question 19

Consequence of blood vessel dilation to skin (CV system)

Answer 19

Increased blood flow and blood pooling at limbs

Question 20

Consequence of decreased blood volume, VR, SV, Q, BP (CV system)

Answer 20

Increased HR to compensate, reduce O2 transport to working muscles

Question 21

Consequence of dehydration (R system)

Answer 21

Inc mucus production, airway constriction, dec air volume for gaseous exchange

Question 22

Consequence of increased breathing frequency (R system)

Answer 22

Increased oxygen cost of exercise (EPOC)

Question 23

Consequence of more pollutants in air (R system)

Answer 23

Airway irritation, asthma symptoms

Question 24

Strategies pre-comp to maximise performance:

Answer 24

7-14 days acclimatisation (inc body tolerance to heat)

Cooling aids to reduce core body temp (delay dehydration effects

Question 25

Strategies during competitions to maximise performance:

Answer 25

Pacing strategies
Suitable clothing to maximise heat loss
Rehydration (hypotonic or isotonic)

Question 26

Strategies post-comp to maximise performance:

Answer 26

Cooling aids

Isotonic refuelling to replace lost fluids/ glucose/ electrolytes