Altitude Flashcards
Short races
lower air density at altitude offers less resistance to high-speed movement
lower PO2 no effect on performance as anaerobic
sprint performances = not affected or improved
improve jumping
Long races
performance demands more dependent on oxygen delivery to muscle
lower PO2
High altitude amounts
same percentage O2, CO2 and N2
lower partial pressure O2, CO2 and N2
2O2
8N2
air 21% O2 but thinner at altitude
Atmospheric pressure
decreases at higher altitude
Hypoxia
low PO2
altitude
reduction in arterial oxygen pressure (PaO2)
= disruption homeostasis triggers neuroendocrine responses that regulate important adjustments in key physiological systems
Normoxia
normal PO2
sea level
Hyperoxia
high PO2
Hypoxaemia
low level oxygen in blood
Side effects of altitude
lightheadedness/headache
insomnia, nausea, vomiting
dyspnoea, anoerexia, GI disturbance
lethargy, general weakness
collapse
Short-term adjustments to altitude
immediate = more O2
ventilation changes = hyperventilation, raises alveolar O2, lowers alveolar CO2, alkalosis
increase for same workloads
cardiovascular changes = increase resting HR and CO
due to lower oxygen content and increased SNA
reduced humidity, dehydration, sunstroke/blindness (UV light)
Changes VO2max
decline with increasing altidude
no adverse for events <2mins
Effects of high altitude on HR response to max exercise
lower max HR - activation PNS
parasympathetic blockade (glycopyrrolate) restore max HR response to exercise
lactate paradox
Benefit acclimatisation
increase minute ventilation after 4 days
increase HR
decrease SV
decrease CO - fall due to Fick’s law
more O2 in blood improves O2 extraction capacity = less reliance on central delivery (less cardiac strain)
Blood changes
polycythemia (increase RBC mass) due to increased EPO
increase O2 carrying capacity of blood 200-310mL/litre
decreased plasma volume
increase Bohr shift
Vascular/ceullar changes
increased capillarisation
increased myoglobin in muscles
increased aerobic enzyme (citrate synthase)
increased lactate comsumption and oxidation by active muscle
a-vO2 difference falls but widens following acclimatisation