lec 19 - exercise in hot and cold

Question 1

what is thermoregulation

Answer 1

process of maintaining a normothermic body temp

Question 2

what are the 4 mechanisms of heat loss

Answer 2

radiation - heat loss directly to environment
convection - heat transferred from skin to colder air or water
conduction - heat loss via direct contact
evaporation - breathing and sweating

Question 3

what does the body do it it needs to warm up

Answer 3

vasoconstriction (decreases blood flow to the skin)
thermogenesis

Question 4

what are the two types of thermogenesis

Answer 4

non shivering - metabolic heat production asscoiated with metabolic burning of brown fat (adipose tissue)
shivering - generates heat as well
— non shivering occurs right before shivering

Question 5

what does the body do it it needs to cool down

Answer 5

vasodilation (increases blood flow to tthe skin)
sweating

Question 6

what are heat illnesses

Answer 6

result of increased heat production and impaired dissipation of heat
mild = heat edema, rash, syncope, cramps
major = heat exhaustion/stroke

Question 7

what is heat edema

Answer 7

normal core temp
peripheral vasodilation to produce heat loss leads to pooling of fluid in extremities (soft tissue swelling)

Question 8

what is the treatment for heat edema

Answer 8

elevation of extremities
hydration and salt intake
compression socks
no diuretics! - can make us lose more blood volume through urine
lasts 7-14 days

Question 9

what is heat rash

Answer 9

normal core temp
sweating saturates the skin and clogs the sweat glands
- obstruction leads to leakage of sweat into the epidermis or dermis
blister like rash on skin

Question 10

what is the treatment for heat rash

Answer 10

(risk of secondary infection from open wounds)
cool the skin adn prevent sweating
loose and light clothing
shower in cool water (let skin air dry)
mild anti-inflammatory lotion (not sunscreen)
lasts 2-3 weeks

Question 11

what is heat syncope

Answer 11

normal core temp
occurs iwth orthostatic hypotension resulting from peripheral vasodilation and venous pooling
low BP = fainting

Question 12

what causes heat syncope

Answer 12

standing still after exercise
older peopel with poorer blood flow

Question 13

what is the treatment for heat syncope

Answer 13

supine in cool location
elevate legs
hydration

Question 14

what are heat cramps

Answer 14

normal or elevated core temp
no clear cause (possible sodium / electrolyte depletion)
occur usually after 2+ hours of prolonged exercise
occur in the active muscle groups

Question 15

what is the treatment for heat cramps

Answer 15

removal from cramps
hydration
light stretching / massage
cooling with ice
seek medical help if they don’t subside in an hour
no training for a few hours after the cramps subside

Question 16

what is heat exhaustion

Answer 16

elevated core temp (37-40)
normal mental and neurologic status
sometimes tachycardia or hypotension
malaise, fatigue, dizziness, heavy sweating, headache, vomiting, cold or clammy skin

Question 17

what is the goal of heat exhaustion treatment

Answer 17

avoid progression to heat stroke
pull athlete asap and get symptoms calmed down so nothing progresses

Question 18

what is the treatment for heat exhaustion

Answer 18

removal from heat
supine position and elevate legs
cool the body (cold packs on neck, armpits, and groin)
hydration
seek medical help if not improvign within the hour

Question 19

what is heat stroke

Answer 19

elevated core temp (40+)
CNS disturbance - irritability, ataxia, confusion, coma, seizures
may or may not be preceded by mild symptoms

Question 20

what are the two types of heat stroke

Answer 20

classic = environmental heat waves (can be from physical exertion or not)
exertional = intrinsic heat production (not necessarily hot environment)

Question 21

what is the goal of heat stroke treatment

Answer 21

lower body core temp to <38.9 within 30 mins
(any longer can lead to long term consequences)

Question 22

what is the treatment for heat stroke

Answer 22

assess ABCs
reduce heat as quickly as possible (cold water immersion)
call medical assistance asap
cool first - transport second

Question 23

what are some complications from heat stroke

Answer 23

seizures
hypotension
arrhythmias
damage of vital organs (kidney/liver)
rhabdomyolysis (life threatening from the breakdown of muscle fibres and leaking their contents into the blood)

Question 24

what is the most important precursor to heat illnesses

Answer 24

dehydration - biggest risk factor

Question 25

what are the IOC acclimatisation guidelines

Answer 25

min 1 week (optimal = 2 weeks) of acclimatisation before competing in a hotter and more humid environment
- recommendation based off of where the individual is coming from

Question 26

what is wet bulb globe temperature (WBGT)

Answer 26

measure of the heat stress in direct sunlight
temp + humidity + wind speed + sun angle + cloud cover
can predict environmental heat stress

different from heat index (measured in shade)

Question 27

how are body weight and dehydration related

Answer 27

<2% BW loss = mild dehydration (occurs commonly in athletes and gen pop)
>3% BW loss = athlete should be restricted until BW recovers with hydration

Question 28

what is hypoatremia

Answer 28

too much water in the system
serum sodim levels <130 mmol/L
symptoms = nausea, vomiting, altered mental status, seizure, coma, death

Question 29

what is the RTS protocol for heat illnesses

Answer 29

mild forms = within 24 hours
heat exhaustion = next day if symptoms are no longer present (gradual return = ideal)
heat stroke = within 1 month

Question 30

when does hypothermia occur

Answer 30

when heat losses exceed heat production
core body temp <35
can also occur after hard exercise (vasodilation occurs for too long and the body loses too much heat)

Question 31

what is the body’s response to losses in heat

Answer 31

shiverign to increase metabolism and heat
superficial blood vessels constrict reducing skin heat loss

Question 32

what are the 3 stages of hypothermia

Answer 32

mild = feeling cold, shivering, incoordination, apathy
moderate = changes in behaviour and appearance, loss of shivering, confusion, slurred speech, decreased physiological functioning
severe = major metabolic and physiologic abnormalities, asystole by 18 deg

Question 33

what is the treatment for hypothermia

Answer 33

passive core rewarming
move to warm and dry place
remove wet clothing (use dry blankets)
don’t apply heat to extremities (can send cold blood to the core)
warm fluids

Question 34

what are the 3 stages of frostbite

Answer 34

frostnip = superficial skin is frozen
mild frostbite (superficial) = freezing of the skin and subcutaneous tissue
severe frostbite (deep) = freezing of the tisues below the skina dn adjacent tissues (muscle, tendon, bone, etc)

Question 35

what is superficial frostbite

Answer 35

involves dermis and/or shallow subcutaneous tissue
skin is red, white, cold, painful, blistering
usually recovers without permanent damage
increased susceptibility to cold injury

Question 36

what is deep frostbite

Answer 36

involves subdermal tissue
skin is white, grey, hard, insensitive, becomes black
leads to loss of tissue / body part

Question 37

what is the treatment for frostbite

Answer 37

rewarming with warm water immersion as long as there is no risk of refreezing
pain meds / antibiotics
important to check for other conditions (hypothermia)

Question 38

what are examples of external and internal risk factors for cold injury

Answer 38

external = cold weather, rain, wind, wet clothes
internal = previous cold injury, body size/comp, sex, medical conditions