Environment & Exercise

Question 1

Thermoregulation

Answer 1

Hypothalamus - maintain around 37 change of 0.1-0.5 produces a neural response

Question 2

Receptor locations

Answer 2

• hypothalamus, cortex, skin, abdomen, great veins

Question 3

In response to Heat

Answer 3

General peripheral vasodilation
increase sweating mechanism
conscious acts
acclimatization: occurs as early as 1-4 days and can take 10-24 days to complete
includes improve circulatory response: better shunting of blood to periphery and improved vasodilation, improved sweat response,— 50-60% occurs due to internal exercise stress
Note: training increases blood volume which rescued circulatory strain that can occur with blood shunting

Question 4

In response to cold

Answer 4

vasoconstriction 
shivering and non-shivering 
goose bumps 
conscious acts 
acclimatization: takes 7 days, reductio in mean skin temp that shivering begins, increase in non-shivering thermogenesis due to thyroxin, intermittent vasodilatation of vessels in periphery

Question 5

Fatal core temp

Answer 5

42 & 30

Question 6

At 41

Answer 6

Hyperthermic:

break down in nerve tissue, local hemorrhage and organ failure

Question 7

below 29

Answer 7

the hypothalamus can’t regulate core temp resulting in circulatory heart failure

Question 8

Below 35

Answer 8

Hypothermia

Question 9

The body gain and loses heat through

Answer 9

Evaporation (25%), convection (related to velocity and temp- 12%), radiation (60%) , and conduction (direct contact and related to the temperature difference- 3%)

Question 10

insensible sweating

Answer 10

25% of heat lost occurs at room temp via insensible skin perspiration and respiratory evaporation

Question 11

Every litre of water is equal to

Answer 11

580kcal

Question 12

Physiological events: exercise in heat

Answer 12

-exercise induced heat stress & environmental heat stress
- increased thermoregulation as core temp rises
-general vasodilation
-sweating and conscious acts
-heat exchange also occurring due to convection/conduction/radiation
-initial stabilization of elevated core temp
If exercise continues may see a rise in core temp
further vasodilation and increased sweating

Question 13

Results

Answer 13

cardiovascular drift, dehydration, electrolyte depletion

Reduction of cessation of sweating
heat stress, exhaustion, stroke and death

Question 14

Physiological events: exercise in cold

Answer 14

non-shivering thermogenesis: increase in sympathetic drive, epinephrine, and thyroxin
Peripheral vasoconstriction
involuntary shivering
Goose pumps

Question 15

Effects of cold on performance

Answer 15

5-6 % drop in VO2 max with a 1 degree decrease in core temp
increase energy expenditure due to non-shivering thermogenesis
cold water increase heat transfer 4 to 5 times greater than air
increased glycogen use in cold due to impaired mobilization of fats

Question 16

Children and heat

Answer 16

generate more heat, less efficient
immature sweat response
lower cardiac output which reduces their capacity to transfer heat from the core to the periphery

Question 17

Children and cold

Answer 17

greater surface to mass ratio -produce more heat to maintain their temp, less subcutaneous fat

Question 18

Is muscle function impaired in cold?

Answer 18

Yes, affects the ability to develop force output and perform coordinated movements
-Motor recruitment is affected by muscle cooling because of disruption of transmission via motor nerves

Question 19

Menstrual cycle and thermoregulation

Answer 19

set point is 0.47 degrees higher during luteal vs follicular phase
Therefore, sweating and vasodilation occur at higher core temps during luteal phase