13 - Altitude Flashcards
at what altitude can an un-acclimatized person lose consciousness within a few minutes during acute exposure to hypoxia?
7000 m
T or F: water loss via the respiratory tract is higher at high altitudes
true
with increasing altitude, does arterial oxygen increase or decrease?
decrease
what happens to cardiac output over the first week at altitude
it falls to or below sea level values for the same VO2 and there is progressive increase in O2 extraction
what is the most important long term adaptation to altitude?
the increase in the blood’s oxygen carrying capacity
______ start to increase during the first two days at altitude due to a decrease in plasma volume and increase in RBC production by bone marrow
hemoglobin
does blood pH increase or decrease at high altititudes?
increases
def: condition where blood pH increases above normal pH
respiratory alkalosis
what sensory and mental functions decrease in performance at altitude
- visual acuity
- light sensitivity
- attention span
- reaction time
- cognition and recall
- pursuit tracking ability
since VO2 max is decreased at altitude, intensity of training must be _______
decreased
what are some adaptation to altitude which should increase VO2 max on return to sea level
- increased hemoglobin concentration
2. local muscle adaptations - increased number of mitochondria, oxidative enzymes
what are some adaptations that hinder performance on return to sea level?
- decreased maximum stroke volume and max heart rate which persists for a few weeks
- increased VE at given workload - extra oxygen goes to respiratory muscles during exercise
- decreased buffering capacity of blood for lactic acid
- specificity of training
what’s the name of the altitude training often used by high performance athletes?
live high - train low
what’s 5 ways top prevent altitude illnesses
- staged ascent
- avoid alcohol and other depressant
- high carbohydrate diet
- appropriate exercise level
- fluid ingestion
when does acute mountain sickness occur?
12-36 hours after arriving at altitude and usually lasts 2 to 3 days
what are the symptoms of acute mountain sickness?
- headache
- fatigue
- irritability
- loss of appetite
- nausea
- vomiting
- dizziness
what is the treatment for acute mountain sickness?
acclimatization or descent
def: accumulation of fluid in the alveoli, decreased diffusing capacity for oxygen
pulmonary edema
what is the direct effect of hypoxia on systemic arterioles
vasodilation
hypoxia in the lung causes…
vasoconstriction
what are the symptoms of high altitude pulmonary edema?
- shortness of breath
- sever fatigue
- cough (bloody)
- tachycardia
- severe headache
- insomnia
what should people avoid for in order to prevent HAPE?
sleeping meds
alcohol
sedatives
how do you treat HAPE?
- descend to lower alt.
- diuretics are effective only if fluids are replaced
- diamox is effective for prevention and treatment
- dexamethasone
def: accumulation of excess fluid in the brain
high altitude cerebral edema
what are the symptoms of high altitude cerebral edema?
- loss of coordination
- confusion
- hallucinations
- severe headache
- severe weakness
what 4 principles is the treatment of altitude illness based on?
- stop ascent in presence of symptoms
- descend if no improvement or if condition worsens
- descend immediately if HACE, loss coordination, or changes in consciousness are present
- ill persons must not be left behind or sent down alone
