7: exercise in unusual environments Flashcards
(47 cards)
Altitude
air is compressible;
a given volume at sea level (SL) contains more molecules than at ALT -
ALT a given volume contains less molecules that at sea level
what is air made up of?
N2=79.04%; Co2=0.03%; O2=20.93%
constant up to 110,000m
What is same at any altitude?
the concentration of gases do not change, but the content per unit volume decreases
What us the partial pressure of nitrogen?
600mmHG
what is the PP of O2?
159 mmHg
what is the PP of co2?
0.23 mmHg
as one move up in altitude, if barometric pressure drops then..
everything else will drop as well
driving pressure to move o2 along the o2 transport cascade is compromised
Ventilation (VE):
the movement of air between the environment and the lungs via inhalation and exhalation
make alveolar ventiatiolation as close to the outside as possible by breathing slower and deeper. but trouble is blowing off co2
Hyperventilation (HV)
changes the partial pressure of oxygen in the alveoli and
improves oxygenation of the blood
hyperventilation: adaptive
the greater the HV the more closely the alveolar air resembles inspired air –facilitates O2 loading in the lungs
hyperventiolation: “non-adaptive”
: decrease es partial pressure of CO2 at the alveolar level and this causes blood pH to increase (alkalosis)
oxyHb curve shifts to facilitate loading
-Bicarbonate is excreted in the urine
at altitude what type of breathing do you want to do?
deep nad slow breathing
CO2 + water –> carbonic acid
-the formation of carbonic acid from CO2 and water
is favored by the high PCO2 found in tissue capillaries
-in the lung there is a low PCO2 and thus the formation
of CO2 and H2O from H2CO3 occurs
why does heart rate go up with altitude?
becuase less o2 so the heart has to pump harder to obtain o2
as you go higher and higher what happens to your heart rate and o2?
altitude 0> icnreaes HR
altitude –> decrease o2
they will meet at one pt and you need to not do anything and just rest
HEMATOLOGICAL CHANGES:
1) Hb concentration (1 g of Hb can carry 1.34 ml of O2)
2) the extent to which Hb is saturated (SaO2)
Exercise in the Heat
–vasodilation –dehydration, –hyponatremia, –heat cramps, –heat exhaustion, –heat stroke evaporation is always NEGATIVE!
Latent heat of evaoporation
The input energy required to change the state from liquid to vapor at constant temperature
Heat Illness:
syndromes overlap and frequently occur in combinations-regarded as a continuum
1) heat cramps
2) heat exchuastion
3) heat stroke
heat cramps
painful muscle contractions which occur during or after work in the heat
Heat exhaustion
characterized by weakness, fatigue, headache, nausea and diarrhea.
Heat stroke
potentially fatal illness, a state of thermoregulation failure characterized by disturbance of the nervous system (poor limb co-ordination, delirium, convulsions, grand mal seizures) by generalized anhidrosis and by a rectal temp above 40.6°C (variability in threshold up to 41.1°C) often hot, dry skin
What happens to HR and SV when temperature increases?
will raise; your HR will hit max at high temperatures
SV will decrease
Cardiovascular drift
Results from
–Dehydration
–Reduction in SV
•HR drifts upward to maintain same Q
