Environmental Effects on Body (A2) Flashcards
Define barometric pressure:
The pressure exerted by Earth’s atmosphere at any given point
What happens to barometric pressure as altitude increases?
Barometric pressure decreases -> pO2 decreases
pO2 at sea level (outside body vs in capillary blood)
159 mmHg vs 40 mmHg
pO2 3600m above sea level (outside body vs in capillary blood) and significance of 3600m
105 mmHg vs 65 mmHg (45% reduction)
3600m = SA FIFA World Cup
pO2 8800m above sea level (outside body vs in capillary blood) and significance of 8800m
43 mmHg vs 3 mmHg
8800m = Mt Everest
What does decrease in pO2 mean for haemoglobin’s affinity for oxygen and % saturation?
Affinity decreases as it can’t pick up O2 at the lungs
Reduction in % saturation
Side effects (5) of low haemoglobin saturation:
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%
Main (2) side effects of low haemoglobin saturation:
Reduction in aerobic capacity and VO2 max
Define acclimatisation:
Process of gradual adaption to change in environment
What are the general guidelines for acclimatisation at (1000-2000, 2000-3000, 3000+, 5000+)?
1000-2000: 3-5 days
2000-3000: 1-2 weeks
3000+: 2+ weeks
5000+: 4+ weeks
Benefits (4) of acclimatisation:
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
Thermoregulation definition:
The process of maintaining internal core body temperature (37 degrees)
Role of thermoreceptors:
Sense change in body temp
Increase in temp leads to heat moved to skin surface and lost via evaporation and convection
Hyperthermia vs Hypothermia
Hyper: Significantly raised core body temp
Hypo: Significantly lowered core body temp
Causes of hyperthermia:
High and prolonged exercise intensity
High air temperature
High relative humidity
Cardiovascular drift definition:
Upward drift in HR associated with high core body temp (1 degree inc can inc HR by 10 bpm)
Effects of heat and humidity exercise on cardiovascular system (2):
Blood vessel dilation to skin
Dec blood volume, VR, SV, Q, BP (dehydration)
Effects of heat and humidity exercise on respiratory system (3):
Dehydration and airways drying (32 degrees)
Increased breathing frequency
High sunlight -> more pollutants in air
Consequence of blood vessel dilation to skin (CV system)
Increased blood flow and blood pooling at limbs
Consequence of decreased blood volume, VR, SV, Q, BP (CV system)
Increased HR to compensate, reduce O2 transport to working muscles
Consequence of dehydration (R system)
Inc mucus production, airway constriction, dec air volume for gaseous exchange
Consequence of increased breathing frequency (R system)
Increased oxygen cost of exercise (EPOC)
Consequence of more pollutants in air (R system)
Airway irritation, asthma symptoms
Strategies pre-comp to maximise performance:
7-14 days acclimatisation (inc body tolerance to heat)
Cooling aids to reduce core body temp (delay dehydration effects
Strategies during competitions to maximise performance:
Pacing strategies
Suitable clothing to maximise heat loss
Rehydration (hypotonic or isotonic)
Strategies post-comp to maximise performance:
Cooling aids
Isotonic refuelling to replace lost fluids/ glucose/ electrolytes
