Environmental effects Flashcards
What is the definition of altitude?
Height above sea level
What happens to barometric pressure as altitude increases?
Decreases
What happens to the partial pressure of oxygen as altitude increases?
Decreases
What altitude is counted as high?
Anything above 1500m
What happens to the diffusion gradient as altitude increases?
Decreases so less diffusion of oxygen occurs
What happens to partial pressure of oxygen in alveoli as altitude increases?
Decreases (called hypoxia)
What does a decrease in oxygen partial pressure do to the diffusion rate?
Decreases rate as decreased oxygen available decreases diffusion gradient
What happens to the oxyhaemoglobin saturation at high altitudes?
Decreases saturation (external respiration)
What does a decrease in haemoglobin saturation cause?
Less oxygen to be transported to muscles (decrease in arterial partial pressure of oxygen)
What does a decrease in the diffusion gradient during internal respiration cause?
Less dissociation of Oxygen from haemoglobin so less Oxygen available to muscles
At high altitudes how does the body maintain oxygen intake?
Increasing frequency, tidal volume and minute ventilation at rest and exercise
What does the cardiovascular system respond to when at altitude?
A low partial pressure of oxygen
What happens to plasma volume in response to low partial pressure of Oxygen?
Rapidly decreases the volume (25% in 2/3 hours) to increase density of rbc’s (haematocrit) to increase oxygen transport
What does a decrease in plasma volume cause?
Decrease in stroke volume due to decreased plasma which increases heart rate to maintain cardiac output
What happens to the maximal cardiac output at high altitude?
Decreases as decreases maximum stroke volume and heart rate
What are the net effects of increased altitude?
Decrease VO2 max/oxygen capacity.
Decrease max aerobic performance as altitude increases.
Increased use of anaerobic energy systems, increasing OBLA and early fatigue.
Decrease intensity/duration of work
How much does VO2 max decrease by?
10% for every 1000m above 1500m
What events are most effected by altitude?
The more aerobic the event the more the athlete is effected
What events most need acclimatisation?
Aerobic
Eg 5,000-10,000m. Team games
What events most suffer from reversibility at high altitude?
Aerobic, can’t train at high enough intensity / for a long enough duration to keep adaptations
What is the effect of altitude on high intensity low duration events?
No effect/improve
Eg Javelin/sprints are improved as thinner air density so less air resistance/drag on sprinter / equipment
How does altitude effect middle distance (800m) performers that use FOG fibres?
Decrease as altitude increases lactic acid, OBLA and therefore they fatigue quicker
What is the definition of acclimatisation?
Process of adapting the body to perform in a new environment (high altitude)
What does acclimatisation prepare the body for?
To perform with a lower partial pressure of oxygen (at above 1500m)
(Won’t fully compensate and won’t regain original sea level VO2 max/performance)
How does the length of time needed to acclimatise change as altitude increases?
More time needed as altitude increases.
What is the optimal acclimatisation level?
2200m for 28 days
What are the generic guidelines for acclimatisation?
Decrease intensity for first few days (60-70% of sea level intensity)
Increase to full intensity as event approaches (2 weeks for full acclimatisation)
Rest days needed if at more than 3000m
What is the extra generic guideline for team / endurance sports?
Weeks of high intensity training at sea level first to increase VO2 max before going to altitude.
Allows performers to compete at altitude with higher intensity than those that don’t do this.
What are the cardiovascular benefits of acclimatisation?
Release of EPO within 3 hours (peaks at 24-48 hours)
Increase of red blood cells.
Breathing rate and minute ventilation stabilise but are still above sea level values
What are the respiratory benefits of acclimatisation?
Stoke volume and cardiac output decrease as gaseous exchange becomes more efficient with low partial pressure of oxygen.
Lower cardiac output during sub-max intensity.
Heart rate remains elevated at rest and during exercise
What are the other benefits of acclimatisation?
Reduced: Altitude sickness Headaches Breathlessness Poor sleep/appetite
What is the best timing of arrival if you don’t have time to acclimatise?
Arrive as late as possible and compete within 24 hours
Why would someone arrive as late as possible and compete within 24 hours at high altitude?
If no time to acclimatise then arriving late means you decrease acclimatisation but perform before the affects of altitude become too great.
Acute altitude effects increase/worsen after 24 hours.
No time for reversibility to occur because of altitude.
Why would you train at lower altitudes of 1500-3000m for 2 weeks before performing?
Allows body to adapt to the hypoxic air environment