environmental effects on body systems✅ Flashcards
define altitude and barometric pressure
altitude: the heigh or elevation of an area above sea level
barometric pressure: the pressure exerted by the Earth’s atmosphere at any given point
what are the effects of high altitude on cardiovascular and respiratory systems
as altitude increases, barometric pressure decreases
partial pressure of O2 decreases
the greater the altitude, the greater the negative impact on the diffusion gradient
what is the partial pressure of O2 and diffusion grafient to capillary blood at sea level, 3600M and 8800M
sea level: 159mmHg, 119 to capillary blood
3600M: 105mmHg, 65 to capillary blood
8800: 43mmHg, 3 to capillary blood
what happens if an athlete competes at high altitude
rate of O2 diffusion decreases, reducing haemoglobin saturation so results in poor transport of O2
blood volume decreases- plasma volume decreases by 25% to allow increase in density of RBC
SV decreases, which increases HR
maximal CO, SV and HR decrease during maximum-intensity exercise
define acclimatisation and erythropoietin
acclimatisation: a process of gradual adaptation to change in environment
erythropoietin: naturally produced hormone responsible for producing RBC
how long does i take for acclimatisation
effects start at 1500M
3-5 days for low-altitude performance (1000-2000M)
1-2 weeks for moderate-altitude performance (2000-3000)
2+ weeks for high altitude performance (3000m+)
4+ weeks for extreme altitude performance (5000-5500)
what are the benefits of acclimatisation for cardiovascular and respiratory systems
increase in RBC production due to increase of erythropoietin
stabilisation of breathing rate and ventilation although remain elevated compared to sea level
reduction of SV and CO as O2 extraction becomes more efficient
reduced incidence of altitude sickness, headaches, breathlessness, poor sleep and lack of appetite
how does body respond to heat
process of maintaining internal core temp called thermoregulation
thermoreceptors deep in core sense a change in body temp
if core temp rises, metabolic heat transported by circulating blood to surface of body and released mostly by sweat
loss of sweat decreases blood volume and causes dehydration
rate of heat loss through sweating affected by humidity
what is hyperthermia caused by
high and prolonged exercise intensities
high air temps
high relative humidity
what are the effects and implications of heat and humidity in cardiovascular system
dilation of arterioles and capillaries to skin- increased blood flow and blood pooling in limbs
decreased blood volume, venous return, SV, CO, blood pressure- increased HR to compensate, increased strain on cardiovascular system, reduced O2 transport to working muscles
what are the effects and implications of heat and humidity in respiratory system
dehydration and drying of airways in temp above 32 make breathing difficult- increased mucus production, constriction of airways, decreased volume of air for gaseous exchange
increased BR to maintain O2 consumption- increased O2 ‘cost’ of exercise
high levels of sunlight increase effects of pollutants in air- increased irritation of airways, leading to coughing, wheezing or asthma symptoms
what strategies are there to maximise performance in heat and humidity
pre comp- 7-14 days of acclimatisation in same conditions to increase body’s tolerance to heat, using cooling aids eg ice vets to reduce core temp and delay effects of dehydration
during comp- pacing strategies to reduce feelings of exertion, suitable clothing to maximise heat loss, rehydration as often as possible with hypotonic or isotonic solutions
post comp- cooling aid, rehydration using isotonic solutions to replace lost fluids, glucose and electrolytes
