Environmental effects on body systems (1.1d) Flashcards
define altitude
the height or elevation of an area above sea level
define baromatric pressure
the pressure exerted by the Earth’s atmosphere at any given point
when altitude increases what happens to barometric pressure?
it decreases
at higher altitudes the partial pressure of O2…..
decreases
the greater the diffusion gradient….
the faster oxygen will move from one area to another
the greater the altitude the greater the neagtive impact on….
the diffusion gradient
at sea level the partial pressure of oxygen is…
159 mmHg
at 3600m above sea level the partial pressure of oxygen is…
105 mmHg
at 8800m above sea level the partial pressure of oxygen is…
43 mmHg
at sea level the diffusion gradient to capillary blood is…
119
at 3600m above sea level the diffusion gradient to capillary blood is…
65
at 8800m above sea level the diffusion gradient to capillary blood is…
3
if an athlete competes at a high altitude what happens to the rate of oxygen diffusion?
it decreases, reducing haemoglobin saturation and resulting in poor transport of oxygen
what happens as a result of a decreased diffusion gradient, reduced haemoglobin saturation and poor O2 transport?
- blood plasma volume decreases by 25%
- SV decreases, which increases HR
- max cardiac output, HR and SV decrease during max exercise
what is the impact of training in high altitude on aerobic capacity and VO2 max?
causes a reduction in aerobic capacity and Vo2 max
define acclimatisation…
a process of gradual adaption to a change in environment
define erythropoetin..
naturally produced hormone responsible for producing red blood cells
at what height does altitude start to have an effect?
1500m
how many days does it take to acclimatise for low altitude (1000-2000m) performnace?
3-5 days
how long does it take to acclimatise for moderate altitude performance (2000-3000m) ?
1-2 weeks
how long does it take to acclimatise for high altitude performance (3000m+) ?
2+ weeks
how long does it take to acclimatise to extreme altitude performnace (5000-5500m) ?
4+ weeks
the acclimatisation benefits on the cardiovascular system are:
- increased red blood cell production
- reduction of SV and cardiac output as O2 extraction becomes more efficient
the acclimatisation benefits on the respiratory system are:
stablisation of breathing rate and minute ventilation
(although they may remain more elevated at rest than when at sea level)
define thermoregulation
the process of maintaining internal core tempertaure
what senses a change in body tempertaure?
thermoreceptors deep in the core
how much sweat can an athlete lose when exercising in the heat per hour?
2-3 litres
what does loss of sweat cause?
a decrease in blood volume
and dehydration
heat loss through sweating is caused by…
humidity
define dehydration
loss of water from body tissues, largely caused by sweating
define humidity
the amount of water vapour in atmospheric air
define hyperthermia
significantly raised body tempertaure
what 3 things cause hyperthermia?
- high and prolonged excercise intensities
- high air tempertaures
- high relative humidity
during prolonged exercise in the heat a rise in body temperature can cause..
cardiovascular drift
cardiovascular drift is..
an upward drift in heart rate associated with a rise in body temperature
what are 3 effects of heat and humidty on the cardiovascular system?
- dilation of artieroles and capillaries to the skin
- decreased blood volume
- decresed venous return
- decresed SV and cardiac output
- decreased blood pressure
when heat and humidity causes the dilation of arterioles and capillaries to the skin, what effect does this have on the athlete?
increased blood flow
increased blood pooling in the limbs
when heat and humidity causes decreased blood volume, venous return, SV, cardiac output and blood pressure, what effect does this have on the athlete?
inreased HR to compensate
increased strain on the cardiovascular system
reduced O2 transport to working muscles
what effect does heat and humidity have on the respiratory system?
- dehydration and drying out of airways in tempertaures above 32 degrees make breathing hard
- increased breathing frequency to maintain oxygen consumption
- high levels of sunlight increase the effects of pollutants in the air
when heat and humidity causes dehydration and drying out of airways what effect does this have on the athlete?
increased mucus production
constriction of the airways
decreased volume of air for gaseous exchange
when heat and humidity causes breathing frequency to increase what effect does this have on the athlete?
increased oxygen ‘cost’ of excercise
when heat and humidity increases the effects of pollutants in the air, what effect does this have on the athlete?
increased irritation of airways, leading to coughing, wheezing or asthma symptoms
how do you maximise performance in the heat pre-competition?
(2 methods)
7 - 14 days acclimatisation
use cooling aids e.g. ice vests
how do you maximise performance in the heat during competition?
pacing strategies
wearing sutable clothing to maximise heat loss
rehydration with hypotonic or isotonic solution
how do you maximise performance in the heat post competition?
use cooling aids e.g. fans
rehydrating using isotonic solutions
