P1 - Environmental affect's Flashcards
What is barometric pressure and what happens to barometric pressure as altitude decreases?
As altitude increases, barometric pressure decreases, even though the composition of the air remains the same (20.9% O2).
This means the partial pressure of oxygen decreases as altitude increases
What is the impact of altitude on gas exchange?
At higher altitude there is a lower partial pressure of 02, so the diffusion gradient is lower so gas exchange happens at a slower rate
At what altitude does exercise have an impact on exercise? what affect does this have on the aerobic system?
Altitude has little impact on activities below 1500m
For every 1000m above 1500m, VO2 max drops by 8-11%
Faster ATP/PC and glycogen usage
Greater lactate production
Faster OBLA
Early fatigue
What does Acclimatization mean? how long does acclimatezation take for what altitude? (1000-2000m) (2000-3000m) (3000m+)
This is the process of adapting to a change in your environment, where partial pressure of oxygen is lower.
3-5 days for low altitude (1000-2000m)
1-2 weeks for moderate altitude (2000-3000m)
2+ weeks for high altitude (3000m+)
what are the Immediate impacts on the body of altitude? and on performance? What happens after 1500m?
Blood volume decreases (by up to 25%)
SV decreases (increasing HR)
Slightly raises Q (cardiac output)
Rate of O2 diffusion decreases
Reduces Hb saturation
Increases breathing frequency
Maximal Q, SV and HR decreases
Reduces aerobic capacity
Reduced Vo2 max
Limited effect on performance UNDER 1500m
For every 1000m above 1500m, Vo2 max drops by 8-11%
So, at the summit of Everest, the anaerobic energy system is needed to maintain energy production
Causing lactic acid production and early fatigue
what are the Benefits of acclimatisation for the CVR systems (Long Term Adaptations)
synthesis of EPO within 3 hours of exposure, which peaks 24-48 hours after. This increases RBC count.
4500m+, RBC count can increase by 14% in 6 weeks
Encourages oxygen carrying capacity of the body.
Q and SV reduce as O2 extraction becomes more efficient
Delays OBLA and increased tolerance to lactic acid
Increase VO2 Max
what are the negatives of altitude training?
Cost
Altitude sickness
Difficulty training at high intensities for long periods so overall training quality is lost initially
Detraining (after)
Benefits are quickly lost when back at sea level (few days)
what are the effects of exercising in the heat? what is thermoregulation? how much sweat can athletes lose in 1hr? how much does 1% drop in body weight affect performance? how does humidity effect sweating? (humidity is % of water in the air)
Thermoregulation is the process that allows the body to maintain core temperature.
Thermoreceptors detect changes in temperature, and cause vasodilation of arterioles, increasing blood flow to the skin.
Heat is also lost by evaporation (sweating) and convection.
Sweating is key for heat loss, BUT does lead to fluid loss.
Some athletes can lose 3+ litres/ hour in hot conditions
This leads to dehydration which will impair performance
1% drop in body weight, can cause a 10-15% reduction performance (muscle power output)
Low humidity increases sweating
High humidity decreases sweating and the cooling process
what is the definition of Cardiovascular Drift? how much does a 1 degree rise in temperature effect HR?
Cardiovascular Drift is the potential side effect of exercise in a hot climate.
This leads to an increase in Heart-Rate during sub-maximal exercise’.
A 1 degrees rise in temperature will cause an upward drift of HR by 10 bpm.
How does the cardiovascular drift affect the body? how does the thermoregulatory system kick in? how are lungs affected? what events affected?
Redirection of blood flow to the skin reduces blood flow to the muscles and venous return.
Fluid loss & therefore blood plasma through sweating results in increased blood viscosity (thickness).
As a result - Stroke volume decreases, causing HR to increase to maintain Cardiac Output (Q.)
Reduced O2 to working muscles
Earlier fatigue
Dehydration
Drying of airways (above 32C) lead to;
Increased mucus production
Constriction of airway
Decreased volume of gas exchange
Increase breathing rate leads to increased oxygen cost of exercise and reduced aerobic energy production
High levels of sunlight causes pollutants (e.g. dust) which can irritate airways
Many anaerobic events not affected, just aerobic as long distance.
How long would u acclimatise for pre comp in hot weather?
7 - 14 days
