A.2: Environmental Factors and Physical Performance Flashcards
Conduction
- Heat from the core moves via blood to tissues and skin
- The colder the environment, the faster the heat loss
Radiation
transfer of energy waves that are sent out from one object and absorbed by another.
Convection
Heat moved from one place to another through the movement of air/water
Evaporation
- The conversion of sweat to water vapor (liquid → gas)
- Heat from body → environment
- When environment temp > skin temp = evaporation (main form of heat loss)
The cycle between ATP and ADP
ATP + water → loses its phosphate → large amounts of energy released → ADP
To reverse:
ADP + P = ATP (requires energy asw)
A.2.1. Explain the relationship between cellular metabolism and the production of heat in the human body.
- Glucose and oxygen reaction releases energy for ATP, but some energy is lost as heat
- Humans require energy to produce heat to maintain internal body temperate at 37ºC
- Only about 20% of ATP energy powers muscle contraction; the rest is lost as heat.
A.2.2. State the normal physiological range for core body temperature.
36ºC - 38ºC
A.2.3. Outline how the body thermoregulates in hot and cold environments.
- Conduction
- Convection
- Radiation
- Evaporation
A.2.4. Discuss the significance of humidity and wind in relation to body heat loss.
High humidity:
- In hot conditions → sweat evaporates slower → body overheat
Low humidity:
- Sweat evaporates quickly → dehydration
Therefore:
- Evaporation (sweating) becomes less efficient when humidity is high
A.2.4. Discuss the significance of humidity and wind in relation to body heat loss.
- Wind → cause body to percieve as temperature decrease → hypothermia
Therefore:
- Wind ↓ = Convection ↓
A.2.5. Describe the formation of sweat and the sweat response.
- Hypothalamus/brain detects rise in body temp
- Sympathetic nervous system activates sweat glands
- Plasma is the source of sweat formation
- Sweat is formed in the secretory part of sweat gland
A.2.6. Discuss the physiological responses that occur during prolonged exercise in the heat.
- increased glycogen breakdown
- higher level of muscle and blood lactate
A.2.7. Discuss the health risks associated with exercising in the heat.
- Heat cramps
- Heat exhaustion
- Heat stroke
A.2.8. Outline what steps should be taken to prevent and to subsequently treat heat-related disorders.
- Define what heat cramps is and steps that should be taken to prevent it
Causes:
- Muscle fatigue and sodium loss in sweat
Symptoms:
- Pain
- Involuntary muscle spasms
Prevention:
- Stop exercise; rehydrate
- Massage / Light stretching
A.2.8. Outline what steps should be taken to prevent and to subsequently treat heat-related disorders.
- Define what heat syncope is and steps that should be taken to prevent it
Causes:
- Low blood pressure (Hypotension) and hypodration
Symptoms:
- Headache
- High core temp
Prevention:
- Acclimatize
- Rehydrate
- Reduce exertion on hot days
- Avoid standing still in the heat
A.2.8. Outline what steps should be taken to prevent and to subsequently treat heat-related disorders.
- Define heat exhaution and outline steps that should be taken to prevent it.
Causes:
- Blood plasma volume decreases by excessive fluid loss
Symptoms:
- Fatigue
- Dizziness
- Vomiting
Prevention:
- Remove subject to shaded area / AC area
- Hydrate before / during exercise
- Acclimatize
A.2.8. Outline what steps should be taken to prevent and to subsequently treat heat-related disorders.
- Define heat stroke and outline the steps that should be taken to prevent it
Causes:
- Thermoregulatory failure
- Dehydration
Symptoms:
- Core temp > 41ºC
- Lack of sweating
Prevention:
- Immediate whole body cooling
- Acclimatize
- Adapt to climatic constraints
A.2.9. Describe how an athlete should acclimatize to heat stress. (important !!)
- Perform training sessions in similar environment conditions for 5 - 10 days
- Intensity of training should be reduced to avoid heat-related problems
- Ensure appropriate hydration
A.2.10. Discuss the physiological and metabolic adaptations that occur with heat acclimatization.
- Increased plasma volume
- Increased sweat response
- Reduce rate of muscle glycogen utilization
- More dilute sweat
A.2.11. Outline the principal means by which the body maintains core temperature in cold environments.
- Shivering
- Non - shivering thermogenesis
- Peripheral vasoconstriction
Shivering
- Repeated muscular contraction
- Uses up extra oxygen and glucose/glycogen store
Non-shivering thermogenesis
Cold triggers adrenaline → activates BAT → break down triglycerides → FFA & Glycerol
Peripheral vasoconstriction
- Blood vessels near skin and muscles constrict, keeping more blood in the core.
- Helps maintain core temperature and reduces heat loss.
A.2.12. Explain why the body surface area-to-body mass ratio is important for heat preservation.
- Larger surface area : body mass = heat loss ↑
- Lower surface area : body mass = heat loss ↓
- Higher SA = more sweating → cool skin with evaporation & convection
