Environmental Conditions in Athletics Flashcards
What are the two mechanisms of thermoregulation in cold conditions?
- Non- Shivering Thermogenesis
- Shivering Thermogenesis
What are Non Shivering Thermogenesis and Shivering Thermogenesis?
- Metabolic heat production from sources other than muscle contraction
- Shivering Thermogenesis is heat production as a result of involuntary muscle contractions
How much thermoregulation can be achieved by shivering or exercise in the cold
- Shivering - can increase metabolic heat production by 6 times
- Exercise - by up to ten times
What are the four mechanisms in which heat is dissipated from the skin to the environment?
- Conduction
- Convection
- Radiation
- Evaporation
What is conduction heat loss?
- When the body comes in contact with something cold, resulting in heat transfer from the warm body to the cooler object
- Exaggerated by 5 times with wet clothing
- 25x with water immersion
What is convection heat loss?
- When air (or water) passes over the body, lifting heat away, due to the mass transfer at the boundary layer moving past the skin’s surface.
- Water is 40x more effective than air at convecting heat away from the body
What is Radiation Heat Loss?
- heat released by the body into the environment, and is independent of ambient air temperature,
What is Evaporative heat loss?
- Vaporization of water from the skin’s surface (evaporation of sweat).
- The most effective means of heat dissipation
during exercise.
How likely is a person who has sustained a cold injury to have another cold injury?
- 2-4x more likely than if they had not had a cold injury previously
Where in the brain is the thermoregulatory center?
- Hypothalamus
Why does heat loss affect women more than men
- Surface area to mass ratio is greater
- More surface area for convective heat loss
What types of layers should players wear in the cold?
- An internal layer that allows evaporation of sweat
- A middle layer that provides insulation
- An external layer that allows evaporation of moisture, and is wind and water resistant.
What is the danger point at which the temperature can cause rapid cold injury of exposed body parts?
- Ten degrees F
What is Hypothermia?
- When the body’s core temperature falls below 95 degrees Fahrenheit
What are early signs and symptoms of Hypothermia?
- Changes in motor function, cognition and level of consciousness
- Should be suspected when an individual, following prolonged exposure to cold, shivers, appears clumsy and confused, has slurred speech, and stumbles.
What are signs and symptoms of Moderate to Severe Hypothermia?
- Cessation of shivering
- Very cold skin upon palpation
- Depressed vital signs
- Rectal temperature below 95 degrees Fahrenheit
- Impaired mental function
- Gross motor skill impairment
How should you treat Hypothermia?
- Remove wet or damp clothing and insulate the athlete with dry clothing or blankets
- Passive external rewarming for mild hypothermia (won’t work for moderate to severe)
- This is because of “Core temperature after-drop”: the return of cold blood from peripheral circulation to central circulation that may cause further core hypothermia.
- In moderate to severe: Rewarming should occur slowly, either at room temperature or by placing the affected tissue against another person’s warm skin, and rewarming of the trunk should begin before that of the extremities to minimize the risk of temperature after-drop.
What are the three phases of frostbite?
- Frrostnip
- Superficial frostbite
- Deep frostbite
What is Frostnip?
- Skin cooling below 50 F
- Loss of sensation and micro-vasoconstriction
- No actual freezing of tissue or permanent damage
- Symptoms are burning and numbness
- Skin may be grayish pale, usually exposed face or extremities
- After thawing, skin may be red, flaky, and peel
- Treated immediately by direct heating or protective clothing
What is Superficial Frostbite?
- Involves only the skin
- Below 28 degrees F
- Mostly ears, nose, fingers, toes, extremities
- Painful, then numb and cold, firm, rigid, pale, or waxy to inspection.
- After thawing, large blisters filled with yellowish fluid may develop
What is Deep Frostbite?
- Involves freezing of the skin, underlying tissues and adjacent tissues, including muscle, tendon, and bone
- Signs and symptoms include edema, mottled or gray skin, tissue that feels hard and does not rebound, and numbness or anesthesia
- Skin will appear puffy and turn dark purple.
- Blisters are absent and gangrene may appear.
How should Superficial and Deep Frostbite be treated?
- In Hospital
- If not, should submerge in warm water bath, 98-104 degrees F, 15-30 minutes, or until tissue is pliable and color and sensation has returned
What is Chilblain (Pernio)?
- Exaggerated or uncharacteristic inflammatory response to cold exposure, most commonly in the feet or hands
- Signs and Symptoms: Small erythematous papules with edema, tenderness, itching and pain, in conjunction with exposure to cold, wet conditions
How do parasympathetic and sympathetic nervous systems play a role in thermoregulation in the heat?
- Parasympathetic: Regulates sweating
- Sympathetic: Controls increases in cutaneous blood flow and vasodilation for heat dissipation
Why is exercising in the heat so demanding on the cardiovascular system?
- Has to deliver both sufficient muscle blood flow to support metabolism and sufficient cutaneous blood flow to support heat loss for the body while maintaining blood pressure
What are some of the bodies responses to heat acclimatization?
- Decreased heart rate
- Decreased Rectal temperature
- Decreased Perceived exertion
- Increased plasma volume
- Increased Sweat rate
How long does heat acclimatization take?
- Most in seven days
- Reasonably protective after 7-14 days
- Maximum protection 2-3 months
How much water loss (% body weight) can start to negatively effect the athlete?
- Two percent
- Impairs power production
- Increases risk to exertional heat illness
Is drinking ad libitum during exercise enough for athletes playing in the heat?
- No
- Should pre hydrate
- Hydrate during
- Hydrate after at volume consistent with fluid lost during
When is the use of IV fluids for hydration appropriate?
- Athlete who is unable to ingest oral fluids due to nausea and/or vomiting