Wk4: Performance at Altitude Flashcards
What is the physiologic challenge from altitude?
the progressive reduction in ambient PO2 with increasing altitude produces inadequate hb oxygenation in arterial blood.
Arterial desaturation impairs aerobic physics activities at altitudes of 2000m and above.
What is the affect of altitude on sprint and power performances?
- does not adversely affect them in the short term as they depend almost entirely on energy from intramuscular high-energy phosphates and glycolytic reactions.
What is the definition of altitude acclimatisation?
the adaptive responses in physiology and metabolism that improve tolerance to altitude hypoxia.
What is the effect of reduced PO2 and accompanying hypoxia at altitude?
Stimulate physiologic responses and adjustments that improve tolerance during rest and exercise.
hyperventilation and increased sub maximal cardiac output via elevated heart rate provide the primary immediate responses.
What are the main long term adjustments during acclimatisation?
- re-establishment of acid-base balance of the bodily fluids.
- increased synthesis of hb and abc
- improved local circulation and cellular metabolism.
How does terrestrial elevation affect altitude acclimatisation and how long does it take to acclimatise?
- noticeable improvements occur within several days
- major adjustments require about 2 weeks but acclimatisation to high altitudes requires 4 to 6 weeks.
What happens to VO2 max at altitude?
VO2max decreases 2% for every 300m above 1500m.
a decrement in endurance-related exercise performance parallels reduced aerobic capacity.
Why are you incapable of sea-level VO2 max values at altitude, even after acclimatisation?
altitude-related declines in maximum heart rate and stroke volume prevent any beneficial effects of acclimatisation.
What is the relationship between training at altitude and training at sea level?
training at altitude provides no greater benefit to sea-level exercise performance than equivalent training at sea level.
How can an athlete benefit from altitude training?
- by periodically returning from altitude to sea level for intense training to offset any “detraining” from lower levels of exercise during a prolonged altitude stay.
- The Gammow hyperbaric chamber and hypoxic tent system represent two approaches to creating an “altitude” environment under sea-level conditions.
Changes in alveolar PO2 and VO2max at altitude
- alveolar P02 averages 25mmHg at the summit of Mt. Everest.
- for acclimatised men, this reduces VO2max by 70% to about 15mL O2.kg/-1.min-1.
