environmental exercise physiology Flashcards
what is thermoregulation?
the body’s ability to constantly balance heat production and heat loss
what are thr two sources of heat?
internal = metabolism
extermal = environmental
how does metabolism generate heat?
whenever we break bonds apart for fuel, we generate ATP = 60% loss in form of heat
during exercise, the longer/harder you work out, the more oyur core temperature will go up
what happens when the temperature outside is warmer than inside the body?
it causes core temperature to go up if higher than 40 degrees
can also be road temperature
what are ways for us to lose heat?
1) vasodilation near the skin
2) conduction
3) convection
4) radiation
5) evaporation
what heat loss sources want to have blood vessels close to skin to make them more efficient?
conduction
convection
radiation
what is conduction?
heat transfer through physical contact
how can you cool an athlete through physical contact?
cold towels
mist
cool vests
**not best to dump water on head because water ill soak your clothing, making it more humid = hotter**
what is convection?
heat we produce warms the air close to body, airflow moves warm air away
how can we cool down via convection?
using a fan or going to a place with a breeze will quickly remove the heated and humidified air close to body
how do we cool via radiation?
reduce the effect of radiation (shade)
allow heat to esape (radiate away)
AKA less clothing
what is the difference of sweating and evaporation?
evaporation happens after athlete sweats… sweat needs to evaporate in order to cool us down
what is the greatest source of heat loss when active?
evaporation
why can we only cool from evaporation if we’re hydrated?
if body is dehydrated, you will not sweat = no evaporation
what is the most effective way to lose heat at rest?
radiation
explain heat loss steps
the harder and more muscles you’re using, the faster the core temperature rises =
vasodilation close to skin =
radiation, conduction, and convection is more efficient to ramp up evaporation at same time =
core temperature back down to 37 degrees
what is the effect on evaporation when there’s humidity?
it it’s humid outside and you sweat, the air won’t be able to accept anymore moisture = no evaporation
what is the main receptor for our body’s thermostat?
central thermoreceptors = anterior hypothalamus
- measures temperature of the blood
peripheral thermoreceptors = on skin
- measures temperature around you
what are some thermoregulation effectors?
(what anterior hypothalamis does)
1) eccrine (ramp up) sweat glands
2) smooth muscle in blood vessels close to skin
3) skeletal muscle
- cns telling you not to exercise because core temp. already rising
4) endocrine glands (thyroxin)
explain a thermoregulation feedback loop
1) increased blood/internal temperature
2) hypothalamus detects rise
3) vasodilation occurs in skin blood vessels
4) sweat glands become more active
5) body temperature decreases
what is a physiologic response to blood when we exercise in heat?
redistribution of blood
- redirection near skin for cooling
drop in aerobic performance due to blood going from muscles to skin
what is a physiologic response to energy systems with exercising in heat?
less access to o2 = slight drop of o2 in muscles
demand for glycogen increases due to lack of o2
earlier fatigue
what is a physiologic response to fluid balance when exercising in heat?
higher by-product concentrations
ex: lactate
how do we lose electrolytes with training?
body starts manipulating hormone levels
(aldosterone)
the more fit you are, the less electrolytes we lose in our sweat
what are heat related disorders?
1) heat cramps
2) heat exhaustion
3) heat stroke
what are heat cramps and how do we treat them?
imbalance of sodium and potassium and sometimes ions inside muscle
ex: sodium wants to regulate water levels outside cell, potassium wants to do opposite.. when sweating we lose a lot of water from outside of cell = sodium levels in muscles drop = cramping in muscles
treatment: cool & fluid and electrolytes
what is heat exhaustion and how do we treat it?
full body effect
- after cramps
- dizzyness/fainting
- ecessive fluid loss
- ramp up HR = tiring to body
treatment:
- cool
- raise feet
- electrolytes/I.V
what is heat stroke and how do you treat it?
high core temp
- dry skin due to dehydration
- rapid pulse for cardiac output
- unconsciousness since the body is pushed so out of homeostasis that it shuts down as a last defence mechanism
treatment:
- cool immediately
- medical attention
what are some exercise recommendations to prevent hyperthermia?
1) be aware of humidity
2) be aware of temperature
3) ensure hydration
4) wear proper clothing
what is the purpose of heat acclimatization?
get to place of competition a couple days earlier to adapt
adaptations that occur:
1) brain ignores inhibitory sensory feedback
2) increased sweat rpoduction
3) less electrolyte loss
4) increased glycogen storage
