Altitude Flashcards
(25 cards)
what is partial pressure
the pressure exerted by an individual gas held in a mixture of gases
what is a diffusion gradient
the movement of a gas across a membrane down a gradient, from an area of high conc/pressure to an area of low conc/pressure
what is altitude
the height above sea level
what height above sea level is considered as altitude
2,400m
what is barometric pressure
- the pressure exerted by the earth’s atmosphere at any given point
what is the relationship between barometric pressure and altitude
- as altitude increases, barometric pressure decreases
- air thins out
- the composition of air stays the same (20.9%) of oxygen, the ppo2 decreases
what is the effect of the decrease in ppo2 with an increase in altitude
- all gases move down a pressure gradient from an area of high to low partial pressure, diffusing from alveoli to the blood and then to the muscles
- the greater the diffusion gradient, the faster the o2 will move from one area to another
- the greater the altitude, the greater the negative impact on the diffusion gradient
what are the effects of altitude on the performer
- breathing frequency increases to maintain oxygen consumption
- blood volume decreases because plasma increases to increase density of red blood cells to maximize oxygen transportation
- stroke volume decreases within the first few hours, during sub-max intensity, leading to an increased HR and slightly higher cardiac output
- maximal cardiac output, stroke volume, and heart rate decreases with altitude during maximal intensity exercise
- reduced aerobic capacity/VO2 max
what are the effects of high altitude on the performer
- lower rate of oxygen diffusion
- lower haemoglobin saturation
- reduced transport of oxygen to muscles
how can altitude have a positive effect on the performer
- lower air density which decreases aerodynamic drag + air resistance –> meaning faster speeds in sports like alpine skiing + speed skating
- it affects (in general - not +ve or -ve) the timing and technical components - balance and proprioception
what happens above 1,500m
- every 1,000m above 1,500m, there is an 8-11% decrease in VO2 max
- there is little effect below 1,500m
- greater demand on the anaerobic system, leading to increased lactic acid at sub-max intensity and early fatigue
what is the effect on training
- coaches must prepare the athletes for performance at altitude - allowing extra time + practice
- increase work:relief ratios
- consider more frequent subsitutions
- supplement oxygen on the sidelines
what is acclimitisation + at altitude
- the process where the athlete gradually adapts to change in their environment (for altitude - lower ppo2 in atmospheric air) –> this will enable them to compete at altitude as normal
- when they return to sea level, there’s a positive effect on performance due to increased red blood cells (only lasts approximately 2 weeks)
- no matter how long an individual spends at altitude prior to an event, they will never fully compensate + regain sea-level VO2 max
- for endurance athletes who rely on oxygen for energy production, acclimitisation is essential prior to an event to minimise the impact of the decreased pp02
what are the acclimatisation guidelines
- 3-5 days for low altitude (1,000-2,000m)
- 1-2 weeks for moderate altitude (2,000-3,000m)
- 2+ weeks for high altitude (3,000m+)
- 4+ weeks for extreme altitude (5,000-5,500m)
what are the effects of acclimatisation on the CV and respiratory system
- release of erythropoietin (EPO) (within 3hrs of altitude exposure) peaking 24-48hrs later which increases RBC production
- within 6 weeks at 4,540m altitude, there’s a 14% increase in RBCs
- breathing rate and ventilation stabilises, however still remain elevated at rest + during exercise when compared to sea level
- stroke volume and cardiac output reduce as oxygen extraction becomes more efficient. After 10 days of exposure, cardiac output is lower at sub-max intensity compared to sea level, while HR remains elevated
- reduced altitude sickness, headaches, breathlessness, poor sleep, lack of appetite.
what are the different types of acclimitisation
- train high, live low
- train low, live high
- train high, live high
what is training high and living low
hypoxic mask or tent to train in, live as normal at sea level
what are the positives of training high and living low
you don’t feel the effects of altitude sickness
what are the negatives of training high and living low
- it will take time to acclimatise
- training intensity/duration will be affected negatively
what is training low, living high
train as normal st sea level, sleep in hypoxic tent
what are the positives of training low, living high
training intensity can remain the same
what are the negatives of training low, living high
you won’t get used to training in hypoxic conditions
what is training high, living high
you train and live at altitude
what are the positives of training high, living high
you acclimatise quicker/more quickly
