LEWIS: Thermoregulation Flashcards Preview

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Flashcards in LEWIS: Thermoregulation Deck (25):
0

During exercise heat is produced as a waste product of

Muscle contraction

1

Necessary to lose that heat in order to keep body temperature constant so blood is moved from the core to close to the surface of the skin, from here heat can be lost to surrounding environment by 4 mechanisms:

1)CONDUCTION
2)CONVECTION
3)RADIATION
4)EVAPORATION

2

Conduction involves the

Transfer of heat through direct contact, from warm skin to clothes and air

3

Convection involves transfer of heat by

Gases
Air passing over our skin takes away air molecules that have been warmed by the skin

4

Radiation is the main way we lose heat when we are

resting

5

Evaporation is the main way we lose heat during exercise
As fluid evaporates from the skin

Heat is lost

6

Sweating, to work as a cooling system, the sweat must evaporate from the

Skin's surface

7

Sweat that stays on the skin's surface or that drops off provides little or
No

Cooling effect

8

Humidity of surrounding air is high, sweat evaporation is

Limited

9

Humidity is low, sweating becomes

Easier

10

Internal body temp =

37•C

11

Changes in body temperature are detected by receptors and information is sent to the hypothalamus, which starts mechanisms such as

Sweating
Vasodilation (increases blood flow to skin)
Shivering (when cold)

12

BLOOD, during exercise has 2 main functions:

1) supply muscles with nutrients and oxygen
2) supply the skin to allow heat to be lost

13

Blood - when exercising in a warm environment a large proportion of the cardiac output must be shared by the skin and the working muscles, this in turn

Reduces the volume of blood returning to the heart and so reduces the stroke volume

14

The heart, in order to maintain cardiac output required there has to be a gradual increase in heart rate (cardiovascular drift)

But these changes are limited in their effectiveness in terms of performance

The combination of a high rate of heat production from the exercise and a restricted capacity for heat loss can lead to

Hyperthermia (high body temperature)

15

Heat exposure combined with exercise results in hypohydration if fluid losses are not

Replaced

16

Fluid loss can lead to:

Symptoms of dehydration such as lethargy, nausea, loss of appetite, anxiety, inability to concentrate

17

Dehydration can eventually lead to

Exhaustion
Heat stroke

18

Dehydration limits performance by:

Decreasing blood plasma volume which results in less oxygen being delivered to the exercising muscles and increase breathing & heart rates

19

In order to prevent dehydration, attention to fluid intake:

Before
During
After

20

Drinks containing carbohydrate and electrolytes are useful for

Recovery, providing carbs for glycogen storage and promoting fluid retention

21

Performance deteriorates in cold environments, the body attempts to gain heat by

Shivering and by vasoconstriction of arteriolar near skin surface

22

Heat loss is increased by wind, which increases convection
This effect is known as

Wind chill

23

Cold reduces the strength of muscles - they can

Generate less force
Produce more lactate

24

During continued exercise in the cold, energy supplies quickly reduce and exercise intensity declines, and the performer becomes increasingly likely to suffer from

Hypothermia