Thermoregulation & Exercise in Hot & Cold

Question 1

Homeothermic

Answer 1

body temp is constant

Question 2

conduction

Answer 2

transfer of heat by direct molecular contact (such as body core to adjacent tissues, body surface to clothes or air)

Question 3

convection

Answer 3

transfer of heat by the motion of a gas or liquid across a heated surface (air molecules, water molecules)

Question 4

where is body temp regulated

Answer 4

thermoregulatory centre in hypothalamus

Question 5

what is the normal body temp range

Answer 5

36.1-37.8 degrees celsius

Question 6

4 methods of heat loss

Answer 6

evaporation
convection
conduction
radiation

Question 7

which method of heat loss is occurring when more movement means more heat loss

Answer 7

convection

Question 8

radiation

Answer 8

body heat is given off by in fared rays

Question 9

what is the main source of heat loss at rest?

Answer 9

radiation

Question 10

how much excess heat do you lose by radiation at room temp

Answer 10

60%

Question 11

Evaporation

Answer 11

liquide (sweat) converted to a vapour by heat from the skin

Question 12

what is the main method of heat transfer during exercise and how much heat is lost?

Answer 12

evaporation

80% at exercise and 20% at rest

Question 13

which of the 4 heat loss methods can also make you gain heat

Answer 13

radiation
convection
conduction

Question 14

what does sweat rate depend on?

Answer 14

environmental conditions, exercise intensity, fitness level,
acclimatization, hydration

Question 15

what amount of sweating can happen at exercise?

Answer 15

1L/hr

Question 16

what is the body’s mechanism to increase heat production through muscle activity

Answer 16

shivering

Question 17

what happens with cold stress

Answer 17

peripheral blood flow decreases, blood flow to core increases

Question 18

what are the catecholamines released to increase heat production during cold exposure

Answer 18

epinephrine

norepinephrine

Question 19

what is the problem with exercising in the heat

Answer 19

skin and muscles competing for blood

Question 20

This happens in what situation “ decreased venous return because decreased LVEDV and SV, maintained Q because increased HR and Cardiovascular drift occurs”?

Answer 20

exercise in the heat

Question 21

why does earlier fatigue and exhaustion occur with exercise in the heat

Answer 21

increased rate of glycogen depletion and lactate accumulation

Question 22

Euhydration

Answer 22

normal body water

Question 23

Dehydration

Answer 23

loss of body water resulting in a state of hypohydration

Question 24

hyperhydration

Answer 24

body retains excess body fluids

Question 25

what is the risk of overheating when dehydrated?

Answer 25

impairment of thermoregulation | therefore decreased sweat rate, skin blood flow and SV function & exercise capacity

Question 26

what is the max amount of water loss through sweating during exercise in the heat?

Answer 26

3L/hr

Question 27

what is the main focus of fluid balance?

Answer 27

to maintain plasma volume

Question 28

requirement for water depends on _____

Answer 28

weight

Question 29

insensible perspiration

Answer 29

occurs on skin; non visible and mostly pure water and accounts for 30% of body water losses (always sweating)

Question 30

Voluntary dehydration

Answer 30

loss of body water for a specific task/sport (decreased performance by 10-15%)

Question 31

Involuntary Dehydration

Answer 31

hypo hydration of >2% of body weight leads to decreased performance. common in prolonged exercise events

Question 32

What does fluid loss lead to?

Answer 32

reduction in CV function and temperature regulation, decreased plasma volume and decreased Q, increased core temp

Question 33

what are 3 methods of preventing fluid loss

Answer 33

skin wetting hyperhydration rehydration

Question 34

1lb = how many ml of dehydration after an exercise bout?

Answer 34

450ml

Question 35

electrolyte replacement

Answer 35

sodium | potassium

Question 36

what percent of volume ingested must be made to restore fluid volume

Answer 36

25-50% MORE than the loss

Question 37

true or false: CHO is good for you after exercise

Answer 37

true, benefits exercise performance

Question 38

what do glucose and electrolyte drinks help ?

Answer 38

maintain muscle / liver glycogen | blood glucose

Question 39

post-exercise you should super hydrate with?

Answer 39

water, electrolytes, carbohydrates

Question 40

4 environmental factors that lead to head stress

Answer 40

air temp humidity air velocity amount of radiation

Question 41

what does fitness level influence in heat stress

Answer 41

increased plasma volume, skin blood flow and sweating, earlier sweating and more dilute decreased heat stress

Question 42

what does body comp influence in heat stress?

Answer 42

increased fat means increased heat stress and risk of heat stroke

Question 43

what does hydration level influence in heat stress?

Answer 43

increased hydration means a decreased fluid loss but a similar SV

Question 44

what does gender influence in heat stress

Answer 44

similar acclimatization but men sweat more and earlier at an increased rate

Question 45

what does age influence in heat stress?

Answer 45

few differences but may have impeded heat dissipation because of impaired circulation

Question 46

what does being a child mean for heat stress factors?

Answer 46

decreased Q and decreased blood available to the skin, decreased plasma volume, decreased sweating rate

Question 47

Heat acclimatization

Answer 47

- within a week with 2-4 hours of daily exposure - daily bouts of exercise in heat for 15-20 min - improves ability to eliminate heat because of increased skin blood flow and increased sweat - earlier sweating - lower HR and core temp - less blood needed at skin - decreased reliance on CHO metabolism

Question 48

Heat cramps

Answer 48

cramping of exercised muscles (spasm) | - due to decreased minerals and water

Question 49

Heat exhaustion

Answer 49

CV system cannot meet demand because blood pools in periphery

Question 50

symptoms of heat exhaustion

Answer 50

``` fatigue breathlessness hypotension dizziness fainting weak rapid pulse ```

Question 51

Heat stroke

Answer 51

internal body temp greater than 40 C stopping of sweating rapid pulse and respiration

Question 52

why does O2 consumption increase for a given intensity in the cold?

Answer 52

shivering takes energy

Question 53

acclimatization to the cold

Answer 53

- >increase in blood flow to extremities to avoid cold stress on hands and feet - > enhanced peripheral blood flow