Lecture 20 - Exercise in Hot and Cold Flashcards
What are the mechanisms of heat loss?
- radiation (directly to environment)
- convection (skin to air)
- conduction (direct contact)
- evaporaton (breathing or sweating)
What are the mild heat illnesses?
- edema
- rash
- syncope
- cramps
What are the major heat illnesses?
- exhaustion
- stroke
Heat edema
Causes
peripheral vasodilation to produce heat loss leads to pooling of fluid in the distal body parts (hands and feet)
normal core temp
Heat edema
treatment
- elevate hands/feet
- compressive stockings
- hydration and salt intake
- no diuretics
7-14 days
Heat rash
Cause
sweating saturates skin and clogs sweat glands - leakage of sweat inter epidermis or dermis
normal core temp
Heat rash
treatment
- cool skin and prevent sweating
- loose, light clothing
- shower in cool water, let skin air dry
- mild anti-inflmmatory lotion
weeks
heat syncope
cause
orthostatic hypotension reuslting from peripheral vasodilatiion and venous pooling
normal core temp
heat syncope
symptom
low BP –> fainting
heat syncope
treatment
- supine position
- elevate legs
- hydration
- check injuries
- elevation of cardiovascular and CNS
heat cramps
Cause
not really understood (electrolyte depletion, sodim?)
normal or elevated core temp
prolonged exercise > 2 hrs
What are common muscle groups affected by heat cramps?
- thigh muscles
- calf muscles
- abdominals
- back
- shoulder
heat cramps
Treatment
- removal from activity
- hydration
- light stretching or massage
- cooling with ice
Heat exhaustion
Causes
elevated core temp (37-40)
Heat exhaustion
Symptoms and signs
- malaise
- fatigue
- dizziness
- heavy sweating
- headache
- comiting
- weakness
- cold or clammy hands
- tachycardia or hypotension
Heat exhaustion
Treatment
- remove from heat
- supine, elevate legs
- cool the body
- hydration
- monitor core temo
- seek medical if not feeling better in an hour
Heat stroke
cause
elevated core temp (40 degrees or higher)
Heat stroke
complications
- seizure
- hypotension
- arrtythmias
- damage to vital organs
- rhabdomyolysis
Heat stroke
Signs and symptoms
CNS distrubances:
- irritability
- ataxia
- confusion
- coma
- seizures
Heat stroke
Treatment
- asses ABCs
- reduce heat as quikly as possible (try to get to 38.9 within 30 minutes)
How can you prevent heat illnesses?
- education
- screening
- monitor those at high risk
- no exercising when sick
- RTS after febrile illness - observe carefully
- stay hydrated
- check weather conditions
- schedule outdoor activites
- wear sunscreen
- sleep, diet
- EAP
- ensure acclimatization
What are the IOC acclimatization guidelines?
minimum 1 week, optimal of 2 weeks of acclimatization before competiting in a hotter, more humid environment
What is hypoantremia?
drinking too much water
serum sodium levels <130mmol/L
Whaat are symptoms of hyponatremia?
- nausea
- vomiting
- seizure
- coma
- death
What is the RTS for heat ilnesses?
Mild - Within 24 hrs
Heat exhaustion - next day if signs and symptoms are no longer present
Heat stroke - within 1 month
What is hypothermia?
develops when heat losses exceeds heat production
core body temp <35 degrees
What are the signs and symptoms of mild (35-37 degrees) hypothermia?
- feeling cold
- shivering
- incoordination
- apathy
What is the body’s response to hypothermia?
- shiovering to increase metabolism and heat
- superfifical blood vessels constrict reducing skin heat loss
What are the signs and symptoms of moderate (32-34) hypothermia?
- loss of shivering
- confusion or sleepiness
- slurred speech
- decreases physiologic functioning
- cardiac arythmias may occur
- change of behaviour or appearance
What are the signs and symptoms of severe (<32) hypothermia?
- major metabolic and physiologic abnormalities
- aystsoled (cardiac arrest) by 18 degrees)
How do we treat hypothermia?
- passive core rewarming
- move to warm and dry place
- remopve wet clothing
- cover with dry blankets
- warm fluids
- apply heat to trunk, axilla, and groin (not to extremities)
- monitor closely
What is frostbite?
freezing of body tissues (progresses distal to proximal and superficial to deep?
What are the 3 stages of frostbite? Breidly describe.
- frostnip - superficial skin is frozen
- mild frostbite (superficial)
- involves dermis and/or shallow subcutaneous tissue
- skin is red or white, painful and blistering
- usually no permanent damgae
- increased duture susecptibility to cold injury - severe frostbite (deep) - freezing of tissues below the skin and adjacent tissues (muslce, tendon, bone)
- involves subdermal tissue
- skin is white/gray, hard, insensitive – become sblack
- - loss of tisues or body part
How do we treat frostbite?
- rewarming with warm water immersiom
- pain medication and antibiotis
- check for other injuries and conditions, especially hypothermia
What are external risk ractors for cold injuries?
- cold weather
- wain and wind
- wet clothing
What are internal risk factors for cold injuries?
- previous cold injury
- body size and composition
- sex - female
- medical conditions
What are preventions strategies for cold injuries?
- screening
- education
- hydration and nutrition
- monitor environmental condityions
- proper clothing
- training/competition environment
- EAP
