Exercise O2 Heat & Fluids Flashcards
what is VO2 max?
maximum oxygen capacity at max exercise
how much % energy actually made into mechanical energy?
20%
cardiovascular equation for VO2 =
VO2=Q(CO) x (CaO2-CvO2)
during maximal exercise, how much of CO is used by muscle?
up to 90%!
in order to increase blood flow to muscles, what has to happen?
vasoconstrict other organs like kidneys and GIT, and skin
muscles of brain wins at maximal exercise?
still the brain, it will vasoconstrict even muscles to maintain cerebral perfusion
exercise hyperaemia causes 4:
local metabolic vasodilators(from muscles)
muscle pump (maintain venous return)
conducted vasodilation
functional sympatholysis
why and how do you postural hypotension after a race?
If you just stop after a race, your heart is still going but no more muscle pump to maintain venous return and you get hypotension
cardiac responses to exercise? 4 things
lowers heart rate d/t
- increased stroke volume
- larger chamber size
- expanded blood volume
- better SA node sensitivity
BP response to exercise?
Diastolic(TPR): stable
systolic(CO): slightly increased
water aerobics not good when?
if ppl have cardiac issues as it increases central blood volume
what happens in Cardiovascular drift? 5 things:
- increased HR, decreased SV
- hyperthermia
- dehydration
- increase plasma adrenaline
- peripheral displacement of blood dt/ vasodilation
is there a neural control of circulation?
Yes just thinking about exercising will increase the heartrate
how to people with heart transplants increase heart rate?
gotta wait for the catecholamines to kick in, no vagus or sympathetics
microvascular adaptations to exercise training?
more capillary density and recruitment = better O2 delivery system
Respiratory role in exercise? 4 things
maintain O2
remove CO2
acid-base balance
fluid and temp regulation
during ventiliation times VT1 and VT2, what happens when you hyperventilate?
between VT1 and VT2 you get metabolic acids produced
arterial pCO2 drops as you hyperventilate
increase resp rate in response to O2?
NOPE!
what drive hyperpnea?
- catecholamines
- temperature
- CO2
- muscle afferents
- motor cortical activation
can you increase your VO2 max
yes with training but only 20-30% increase from what you’re born with
what is the main limitation to VO2 max increasing?
O2 delivery
NOT mitochondrial capacity
swimmers lose heat via?
conduction
runners lose heat via?
sweating/convection/evaporation
what is needed for sweat to work?
need evaporation
humidity prevents this = bad day
in 43C heat why does CO increase compared to 25C? how affect elderly?
skin vasodilates to help get rid of heat and that increases demand on CO, why elderly can have cardiac event in heat waves
best strategy for exercise performance for temperature?
warmed up muscles
pre-cooling for cool core
in the same exercise but different temps, what does brain do?
auto-regulates
core temp the same but less power output(lowered in the heat)
dehydration, where does all the fluid come from?
interstitial
intracellular
plasma volume in dehydration?
well protected
after intense exercise, what happens in the kidney?
due to reduce GFR, RAAS is activated to help restore fluid balance with Na+ retention etc.
why drink Na+ in water post exercise?
water follows Na+ so in intestine, there are Na+ transporters and it will absorb more water if Na+ present
prior dehydration in exercise?
impairs performance
