Midterm 2 Flashcards
Heat illness’
Heat Rash - heat rash is the clogging of sweat glands
Exertional Heat Cramps - imbalance of ions due to dehydration
Heat Syncope - fainting , non lethal, due to high body temperature and dehydration- trying ot get blood back to brain quicker
Exertional Heat exhaustion - cell dysfunction due to increased dehydration, water moving out of cells to blood for thermoregulation - serious but non lethal, causing dizziness, confusion nausea,
Heat Stroke - classic: due to old age and medical conditions, increased strain on vascular system, not a lot of sweating
Exertional Heat Stroke- compounded with exercis, not ususally dehydrated - when the body reaches grwater than 40ºc within 10-15 minutes,
can be lethal, need to get out of the heat into shade to cool down the core - -cells stop working, stope sweating but we still heat up and cells dentaurre messing with AP of muscles and neurons
Predisposed
HAMSLLIE
Health
Age
Medications
Socially Disasdvantaged
Length of exposure
Level of acclimitization
Intensity of exurtion.
Environmental factors
Whos at risk?
old people
occupational groups
socially dis dvantaged
cignitive or physical impaired
children
exercisers
the greatest challenge
the greatest challenge is heat and exercise when it comes to regulating tmeperature, MAP, and oxygen deleivery
heat equation
physical work competition for bodies resources + temperature hotter = gradient + humidity (evaporative capacity) = heat illness
Stress Scales
WBGT - wet bulb globe temperature
- Tw - evaporatitive capacity showing us RH
- Td - regular temperature
- globe - black ball showing us absorbative value and emissivity
Humidex - doesnt tell us the radiation not a lot of problems with it
ESI
environmental strain index
5 point scale using Ta, RH and Solar Radiation - still need to know how it works nad get something to meausre RH - gets rid of wet and globe temperatures
Windchill
- 1940s.
- viles of water in the environments - to see the speed of their heat trasnfer loss
wind speed and temperature
doesnt account for the sun
doesnt account for us being heat generatiors,
assumes we are naked
windchill makes us colder becuase of the increased convective heat transfer
Why are Stress scales okay adn why could they be better.?
Stress scales are good to see what the percieved feeling of the environemnt on our body is . it lets us know whats going on around us, but PSI and and CSI can show us what is going on within us
PSI
Physioogical Strain Index
- uses two 5 point
relates Core temp during exericise with HR - 39.5 degress is the safety, anyting close to that tells us to stop exercising
shows Max HR of 180 beatsmin, anything close to that is clsoe the max, we should be doing
- dont need ot add skin temperature because the HR already tells us that our body is pumping an amount of blood ( with some already beign directed towatd the peripheryso skin tmep doesnt reallly tell us anythin gwe dont already know)
CSI
relates core temp to skin temp 66 - 33
core temp being hopellu nothing below 35 and skin temp nothing below 20
we use skin temp here to show us the gradient bewtween core and skin sduring exercise but since the gradient will be big, the skin tmep doesnt really matter hence 33. shjowing thta we will be warming up the blood anyway
good things about csi and psi
different clothes and climates
different levels of hydration and exercise intensity
men and women
fitness and acclimitizzation
being taller in a marathon
not good because you have to much SA and harder to dissapate
optimal running temp
10-15º c
Ways to precool
microenvironemnt
cooling vest
ice sluhy
ice bath
head cooling
Microenvironemtn cooling suit
doesnt get all parts of your body for most optimal conductive radiation
uses a power bank
hard to use in exercise
needs to be tight and light
maximize cooling efficientfy
maintian thermoneurtality
minimize power and coolant requirment s
Cooling vest
Phase chanign gmaterial.
greatest effect ewith material that has melting point higher than 20ºc
light, doesnt get all parts of your body
decreasees body temp
lets runners go longer in exercise
GO LONGER
head cooling
cool the blood going to the hypothalamus
allows for a decrease in core temperature
better than no cooling and greater with full body cooling/ mist
lots of thermo receptors
lower core tmep lower HR lower skin temp
GO longer
LEss strain
Ice bath
coldest water drops temp quickest - cools from inside out
colder the water the increased risk of after drop
the blip in raise in core tmep is due to vasoconstriction, but can maintain a lower core temp during exercise
how do we cool the core with an ice bath
once we get out of the bath the gradient between ciore and skin is very large
blood rushes to the skin gets cooled and borught back to the core
ice slushy
ice slushy cools the core, blood losest to the core
btoh cwi and slushy provide an extra 10 minutes of time to exhaustion
intermittents cooling
cold glove, rest, shirt off
cold glove
coold glove allows for vasdialation within a vaccum, allows for mroe sweat
longer time to exhaustion and longer time to get to a max HR
psot cooling
cold water subnmersion
ice bath post exercise
helps to improve recovery
decrease in body temp should stop at 37.5 to mitigate after drop
we lose heat even after we get out of the bath becasue of the gradient between skin and core and core and out bloood is going to our skin to heat it up and we lose heat from that dropping our temps close to hypothermia
coldest tmeps drop the tmep fasster but anythig less than 20 still works, cool water ittigates after drop
make surt eits circulated - if n ot cirucaluted we increase the temp of the water around us and can increase our temperature, circulated increases convectiive heat transfer
hard to get to to hyperhydration
casue we piss out and dehydrate into euhydration
at rest why are we not hypohydrated
hypohydration is counter acfted byt he thirst need for fluid by hormones
add exercise and we increase the need for fluids even more, but that thirst may not be enough
forced superhydration
forced superhydration can casue swelling in places that dont need to swell, and dilution o fblood plasma (hyponatremia)
how much water do we lose in hour in sweat
0.8-1.4L
573 calories to emit heat
sweat is hypo tonic
means that it has llw osmolarity
hyperosmotic
high concetration of ions (pulls water toward it)
Dehydration cause and effect?
Dehydration causes a decrease in blood volume water. to bring blood bakc to normal levels, the bloood at a hihg concentration pull swater from interstitail fluid which pulls water from the cell. can casue cell dysfunction
Cardiac output and dehydration
dehydration casues a loss of blood volume water, this increases the thickness of the blood decreaseing the SV, a decrease in SV casues a compensatory effect for the HR to increase.
BW loss
as we loose body water we increase HR anddecrease SV
decereaseing CO
less BW we lose the better, up to and less than 2% loss is best
can measure bw ore and post ot see our hydration level
less water you have the more we sweat
we sweat more because we increase our core tmep and therfore try to thermoregulate more and sweat more .
exercise capacity v02 max
at specific temperatures we can lose exercise capacity as the tmerature decreases.
bw loss capacity also decrease the amount of exercise capacity 5% BW loss calls for 30 % reduction in v02max
2% BW loss doesnt do much
mnore RBC
this means that we have less Blood volume and vice vers
urine assensment
gravity, osmolarity(concentration) , colour, density
blood assessment
asses hematocrit
assess plasma volum e
assess concetration
assessing BW
body weihgt assesemnt doesnt accoiunt for
cho water storage
water shift to ISF
electrolytes
can wmeausre before and after exercise to see the amount lost
Hyponatremia and overhydration
increased water dilutes the blood,decereaseing the concetration of salt, makes isf hyper osmotic, pulling water from blood to it , this can casue sweeling in the braiin
if you add exercise we retain more water in the blasdder becuase we decrease urine output
rehydration prior
80 mins before can hekp decrease core tmep and HR
during exercise
post exercise rehydration
150% 6 horus after to get to normal,. this shoul dnot be pure water casue that shit causes hyponatremia
goal of fluid compostiion
hydrate - 600 ml of water 15ºc
cho- 6-8% carbs (sweeter can make us not absorb properly -
Na+- soiduim torpelenish the salt lost in sweat, avoid hyponatremia _ sodium can increase gastric emptying salatier drinks we tend to dirnk more of
whatis vaso contriction
- increases blood pressure, inceases heart rate, deceases heat transfer,
limits the supply of oxygen and nutrients to the area of vasoconstirction
we do this in response to cold - makes us heat up more in order to maintain the core heat
iuncrease in SNS output by catacholmines to vasculature
cold pressor test
in relation to vasoconstriction, submerge hand into ice bath, measure BP
Cold Induced VasoDilation
every 10-15 minutes we send blood to our peripheryheating it up to a point hotter than normal
dont really know why this happens
but this occurs mostly in those who are exposed to the cold for the longest
we all have the capacity to do it but not all of us show it,
allows us to move blood tot he periphery but trade off is that we lose heat through the blood at the periphery
we do this until a certian point then stop casue we cant afford to lose anymore heat
Therfore - reduces ischemia
maintains tissue function
shivering
shivering is occuring form the removal of inhibiton in the primary centre for shivering in the hypiothalamus
we can see stimulation at the slightest drop from 37 degrees
it is an increase in Ach tone to the motor neurons casuing increasesd involutnry muscle contraction
shivering order
shivering starts at the jaw then the runk then the periphery to protect what is most important
larger muscles shiver at higher muscle intesities
if we are acclimitizzed ot the cold we will start shivering later on in order to save energy
staying in the cold longer than others
some people may have more body fat% increaseing insulation with layers of tissue around the cor , as awell as an increased shivering intesity
non shivering thermogenesis
occurs because of the uncoupling protein found in adipose tissue mainly also sometimes found in wat
liver cardiac skeltal tissue
the uncoupling protein uncouples the atp creeation and the Hydrogen moving that occurs in aerobic respiration. it allows us to produce heat wihtout having tio create/waste ATP (energy)
still needs glucose as its main source
cold stress factors to increase heat
makes us want to eat - thermogenic effect of feeding
moving around
clothing allows us to control the tmeprarute that we are at
base layer - for sweat wicking and moving water away from us
insulation layer - for creating another microenvironemnt, more distance to keep heat in
protective layer from rain and wind
COLD acronym
stay Clean
avoid Overheating
Loose and Layered Clothing
Dry clothing
COLD
