altitude Flashcards
low altitude
500-2000m leth, calg, denver
mod altitude
2000-3000 mt temple, right outside lake louise
high altitude
3000-5500m pikes peak
extreme altitude
> 5500, mt everest
why do you get mountain sickness in planes
because they keep it at 2000m
Partial pressure of oxygen and altitude
decrease as latter increases
mt everest
1921, 1924, 1953, 1978
mallory - reconnaissance (7020)
mallory and irving - dont know
hillary and tensing - first successful summit
messner - first summit w/o o2
arterial blood on mt everest
little oxygenation - 30mmhg in femoral blood
death zone
8000 metres - wont be able to survive
rob hall
commercialization - competition, survived the night in death zone till the next day till 530 pm
hypobaric hypoxia
lower total pressure - go to everest without going to everest - expensive and challenging because of the pressure diff inside and outside of the chamber
normobaric hypoxia
environment made hypoxia by reducing oxygen in the air (% of gases)
Haig Glacier Becky Scott High performance training centre
2700m
acute changes at altitude of arterial blood
reduced oxygenation of arterial blood
decreased PAO2 - decreased SaO2
decreased PAO2 increases time for PAO2 to equilibriate with PaO2
why are highly trained ind not protected from the effects of altitude
reduced transit time with exercise further reduces the O2 saturation of arterial blood
how to increase O2 in arterial blood
increase minute ventilation
- decreased SaO2 will lead to an increase in minute ventilation (increased frequency) at rest and during submaximal exercise in order to increase PA O2 and SaO2%
- hyper ventilation leads to decreased PAcos which decreases ventilatory drive and induces alkalosis,
how to increase O2 delivery to tissues
increase HR and MAP activation of the SNS
- increase HR at rest and during submax,
-vasoconstricion -increases TPR which contributes to overall increase in MAP-
predisposes to high altitude pulmonary edema and high altitude cerebral edema
- increased production of lactate - more fatigue
acute changes at altitude
reduced oxygenation of arterial blood
increase VE in order to increase O2 in arterial blood
increased HR and MAP in order to increase O2 delivery to tissues
effects of altitude on VO2 max
declines by 1% for every 100m increase in altitude (when over 1500m) - pikes peak - lowered by 27%
- everest - lowered by 75%
what else does altitude do to aerobic endurance exercise
earlier onset of fatigue
does altitude affect sprint, strength, and power exercise performace?
yes but not to the same extent
why might anaerobic exercise performance improve at high altitude
they dont require oxygen and theres less pressure/air resistance
acclimatization
adaptive physiological responses
rapid altitude acclimatization
INCREASED ARTERIAL OXYGEN CONTENT
INCREASED DELIVERY OF OXYGEN
how is the arterial oxygen content brought up
- reduced plasma volme (increased urination) - increasd hematocrit (more ability for O2) and decreased Q
- erythropoietin release - stimulates production of RBCs
how is the delivery of oxygen increased -2
reduced bicarbonate which increases CO2 (decreased pH) which causes a right shift in the oxyhemoglobin dissociation curve and increases VE
increaese in 2,3 DPG (diphosphoglycerate)
which is a metabolic by-product of RBCs, causes a right shift, and its beneficial up to 5000m, beyond that SaO2% is impaired
4 chronic adaptation to altitude acclimatization
increased VE(VT)
increased blood volume
increased hematocrit (increased RBC from EPO)
reduced diffusion diff
how does chronic adaptation work with acclimatization
increased myoglobin (increased oxygen carrying capacity of tissues) stimulation of angiogenesis in lungs and muscles
traditional altitude training
live and train at high altitude
benefits: increase in RBC, HGB, Hct, vascularization
negative: decrease in plasma volume, @, buffering capacity, increased viscosity of blood - fatigue more readily
Live high, train low altitude training
sleep in normobaric hypoxic chamber
benefits: no decrease in plasma volume and some athletes benefit from increased hematocrit
negatives: less altitude stimulus
train high, live low altitude training
rationale - increased training intensity
no clear evidence of increased VO2max
overall effect of altitude training depends on 4
ind response, type of training, elevation, duration etc
acute mountain sickness
mild altitude sickness that leads to headache, nausea, irritability, weakness, poor appetite, vomiting, tachycardia, disturbed breathing
above 2500m: 10-25%
between 4500-5500: 50-85%
takes 1-3 days to resolve
6 risk factors for AMS
history
less than 46 yrs of age - brain atrophy - more room for edema
female- women have more migraines
history for migraines
genetics - hypoxic ventilatory response
- CV fitness is not protective - only more efficient
rapid ascent
how do you adapt to AMS
you cant, you go down to recover
high altitude cerebral edema - 3 symptoms and compromise of?
severe altitude sickness characterized by swelling in the brain due to increased BP and permeability of the barrier
- non-responsive headache and vomiting
- confusion, ataxia, cognitive issues
- drowsiness, unconsciousness, brain herniation, death
endothelial permeability
high altitude pulmonary edema
2 symptoms and possible?
severe altitude sickness characterized by edema and fluid leakage in the lungs due to increased pulmonary BP and permeability of the vascular endothelium
- low exercise capacity, labored breathing, coughing, low SaO2%, cyanosis (turning blue)
- gurgling, pink, frothy sputum
- can lead to death if not treated
gamow bag
used to treat altitude sickness