Week 8 - Thermoregulation and Heat Stress Flashcards
Whats the normal body resting tempreature
36.5-37.5 celsius
Whats core body temperature defined as
Temperature of the hypothalamus, the thermoregulatory centre of the body
How is heat loss physiologically controlled
- Body temperature increase is detected
- Blood vessels dilate, sweat glands secrete fluid and heat is lost.
- This results in heat being lost to the environement
- Then body returns back to normal temperature
How is heat retention physiologically controlled
- Body temperature falls.
- Blood vessles constrict, sweat glands do not secrete fluid and heat is conserved. Shivering generates heat so heat is generated
- Heat is then retained as a result
- Body temperature returns to normal level
How is the heat balance/body temperature maintained
Maintained by balancing heat gain and heat loss
What are some examples of heat conservation/production
Shivering thermogenesis
Voluntary muscular activity
Non-shivering thermogensis
What are some examples of heat loss
Blood reaching the skin
Sweating
Whats a key difference between skin and core temperature
Unlike core temperature, skin temperature is not regulated and varies across the body in response to the thermal environment
Whats the effect of hot humid environments on aerobic performance
Its impaired
Why is aerobic performance effected in hot conditions
There is an increase demand on heat loss mechanisms such as skin blood flow and sweating. There is a reduced gradient between core and skin so therefore core temperature increases
How does dehydration impact heat stress
Decreases sweat rate and plasma volume.
Also a further decrease in cardiac output, maximal oxygen uptake, muscle strength and work capacity
Why is pro-longed high intensity training in hot conditions significantly impaired
This is because there are competing regulatory demands for blood flow between thermoregulation, working muscle and CNS
Also heat-related changes in skeletal muscle function and metabolism
Whats the most rapid way to lower body temperature
Cold water immersion is the most rapid way to lower body temperature
How can you mitigate the impact of heat stress before, immediately before and during exercise
(ON SHEET)
Before - heat acclimation and aerobic training
Immediately before - pre-cooling, hydration status
During - Hydration, clothing and cooling
How effect of the acclimatisation response of improved cutaneous blood flow
Transports metabolic heat from deep tissue to shell