thermoregulation - week 8 Flashcards
what is resting core temp ?
36.5 - 37.5 degrees
what temp can body safely increase up to ?
40 degrees
what temp can the body safely drop down to ?
35 degrees
what can the body’s core temp be defined as ?
temp of the. hypothalamus - thermoregulatory centre of the body
name as many ways to measure body core temp (5)
oesophageal temp (up nose)
rectal temp
stomach (swallowed telemetry pill)
oral temp
tympanic temp (ear)
what is the average skin (shell) temp ?
32-35 degrees
cool is < 30
hot is ≥ 30
what is the thermal gradient ?
heat transfer from core to skin
what is role of central thermoreceptors?
in blood and detect temp changes sending signals to hypothalamus
what are peripheral thermoreceptors ?
sensors in the skin detecting skin temp
describe what happens when core temp becomes too low
blood vessels constrict
sweat glands don’t secrete fluid to conserve heat
shivering to generate heat
what happens when core temp is too warm ?
blood vessels dilate
sweat glands secrete fluid to lose heat
how is heat generated usually in the body ?
metabolism
what external factors can affect our temperature ? (5)
temperature
humidity
air motion
sky and ground radiation
clothing
what is the most challenging environment for exercise ?
hot and humid
hot - reduced ability to cool
- increased gradient
humid reduces evaporation of sweat
what happens during aerobic exercise in heat ? (3)
increased demand heat loss mechanisms
reduced gradient core and skin
core temp increases
how does dehydration effect the body ? (3)
= loss of fluid from the body
reduced sweating and plasma volume
reduced cardiac output, muscle strength, work capacity , O2 uptake
why is high intensity exercise impaired in hot temps ? (3)
thermoregulation to cool down body
increased CO and SV to compensate fro reduced temp gradient to cool down body
leads to decreased power output
what is the effect of this heat acclimatisation response ?
improved cutaneous blood flow
blood redistribution improvement/ more efficient
transports metabolic heat from deep tissues to shell to cool
what is the effect of this heat acclimatisation response ?
effective distribution of CO
appropriate circulation to skin and muscles for demands of metabolism and thermoregulation
what is the effect of this heat acclimatisation response ?
lowered threshold for start of sweating
cooling begins earlier in exercise
what is the effect of this heat acclimatisation response ?
effective distribution of sweat over skin surface
optimum use of body surface for evaporative cooling
what is the effect of this heat acclimatisation response ?
increased sweat output
maximised evaporative cooling
what is the effect of this heat acclimatisation response ?
lowered salt concentration of sweat
diluted sweat preserves electrolytes in extracellular fluid
what is the effect of this heat acclimatisation response ?
lowered skin and core temps and HR for standard exercise
greater proportion of cardiac output to the active muscles
what is the effect of this heat acclimatisation response ?
less reliance of carbs catabolism during exercise
carb sparing
what is hypothermia ?
core temp drops below 35 degrees
what happens when we exercise in the cold ?
more oxygen is used to shiver which an impair performance and decrease abilities
what is the effect of this physiological response in the cold ?
increased submit VO2
decreased exercise capacity in water
greater heat loss
what is the effect of this physiological response in the cold ?
increased ventilation during submax exercise
increased sympathetic stimulation
what is the effect of this physiological response in the cold ?
reduced skin blood flow
peripheral vasoconstriction
what is the effect of this physiological response in the cold ?
lower lipid mobilisation
reduced blood flow to adipocytes
what is the effect of this physiological response in the cold ?
increased lactate concentration
increased carb metabolism
what is the effect of this physiological response in the cold ?
increased central blood volume
peripheral vasoconstriction
what is the effect of this physiological response in the cold ?
decreased HR during submax exercise
increased central blood volume
what is the effect of this physiological response in the cold ?
release of leptin from adipose tissue
increased sympathetic stimulation
what does acclimation to the cold result in ?
higher hand and foot temp- improved peripheral blood flow
lower skin temp where shivering starts
improved ability to sleep in the cold - due reduced shivering
