climate change heat Flashcards
difference between climate change and global warming
climate change = perisistent long term change in avg weather patterns, broader range of changes like rising sea levels, melting ice, drought
global warming = symptom of climate change
how many live in areas highly susceptible to climate change
3.6 billion
what is the 1.5 degree threshold
vital parameter, pledged that by 2100 worlds avg surface temp will have risen by no more than 1.5 degrees compared with pre industrial levels
happened in 2015, 195 nations
alr broken lol on some days
impact of heat on health
inc freq and severity of heatwaves associated with morbidity and mortality - 7000 per year predicted in uk (mortality)
exacerbates CVD, DM, mental health, asthma n other pre existing conditions
urban heat island effect - cities hotter than urban bc of transport, buildings
heatwave definition
period of abnormally hot weather where min and max temps are unusually high - inc night temps which are usually min
what is heat stored in the body determined by - 3
inability to eliminate internally generated heat from metabolic processes
clothing - barrier to heat loss
external heat gain from environment
4 main heat vulnerability factors (physiological)
older and less abled people
specific medical conditions/ drugs
pregnant people
infants and children
4 main heat vulnerability factors (exposure factors)
outdoor and manual workers
sub-par housing or lack cooling access
poor, displaced, homeless people
athletes/ outdoorsy mfs
indirect health impacts of extreme heat - 5
inc transmission of some diseases
health services and facilities
disruptions of critical infrastructure and tech
ecosystem impacts - drought, fire, poor air quality
impacts related to changes in behaviour, risk of accidents
direct health impacts of extreme heat - 4
death
hospitalisation
heat illness/ stroke
exacerbations of pre existing conditions and mental health
what is the body’s physiological response to heat
body responds to heat stress 45 min post exposure - inc if metabolic heat stress/ exercise
can be behavioural and/or physiological
altered behaviours to adap to heat - go indoors, inc water intake
physiological finite response to heat to maintain thermoregulation - sweating, cutaneous vasodilation
what is the internal optimum body temperature
37 degrees
what is body temp regulated by
homeostatic mechanisms, which is controlled by:
hypothalamus negative feedback loop
e.g.
body temp inc, nerve cells, hypothalamus, then we sweat - balance
what part of our body senses changes in temp externally
skin
then drives signals from spinal cord to hypothalamus causing responses to heat
thermoeffecting physiological responses to heat – 4
sweating
cutaneous vasodilation
dec renal blood flow
heat loss via conduction, convection, radiation
how does cutaneous vasodilation contribute to thermoeffecting response
dec central blood volume , redistributes blood to skin
how does dec renal blood flow contribute to thermoeffecting response
RAAS system induces thirst and renal resorption to mitigate dec central cirulation and maintain blood pressure
effect of dec renal blood flow and cutaneous vasodilation
inc cardiovascular strain
what are the modes of heat transfer - body and environment - 4
convection - media carries heat between body and temp e.g. breathing, radiator
conduction - body touching solid mass (minor) sand, ice pack, etc
radiation - infrared portion of energy carries warm energy, rate of absorption of energy correlates to diff in external and internal temp
evaporation - removal of heat via liquid e.g. sweat. proportional to water vapor pressure gradient between skin and environment
elevating body temp impact on heart
inc rate
heart contractility (thus blood flow and sweating)
extended impact of sweating - feedback loop
dehydration
hyperosmolarity
induces kidneys to activate RAAS system
inc thirst
inc fluid intake
role of sweat in thermoregulation
what are the sweat glands
eccrine and apocrine
what are eccrine sweat glands
tightly coiled tube in dermis or hypodermis
can be clear/secretory (watery part of sweat) or dark (secretion of glycoproteins)
travels thru duct and opens at skin surface
