Thermoregulation & thermal stress Flashcards

1
Q

What is a humans normal resting core temperature?

A

36.5–37.5°C

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2
Q

In the heat, core temperature can safely increase up to ? degrees C.

A

40 degrees C

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3
Q

In the cold, core temperature can safely drop to ? degrees C.

A

35 degrees C

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4
Q

What is body core temperature defined as?

A

Temperature of the hypothalamus, the thermoregulatory centre of the body

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5
Q

How can core body temperature be assessed?

A

ROOTS
Oesophageal temperature
Rectal temperature
Stomach temperature (swallowed telemetry pill)
Oral temperature
Tympanic temperature

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6
Q

What range is skin temperature usually at?

A

32-35°C

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7
Q

What is cool, warm, and hot mean skin temp?

A

cool = <30 degrees C
warm = 30-34.9 degrees C
hot = >35 degrees C

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8
Q

Name 4 effectors of temperature regulation.

A
  • adrenal medulla (releases epinephrine)
  • sweat glands
  • skin arterioles
  • skeletal muscles
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9
Q

Describe the physiological control of thermoregulation in hot conditions.

A

body temp increase, afferent info to brain, efferent information causes blood vessels to dilate, sweat glands secrete fluid (heat is lost) - body temp returns to normal

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10
Q

Describe how heat is conserved/produced.

A
  • shivering thermogenesis
  • voluntary muscular activity
  • non-shivering thermogenesis
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11
Q

Describe how heat is lost.

A
  • Blood reaching the skin
  • Sweating
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12
Q

What happens when performing aerobic exercise in hot environment?

A
  • Increase demand on heat loss mechanism (skin blood flow and sweating)
  • Reduced gradient between core and skin - therefore core temp increases
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13
Q

How does dehydration exacerbate heat stress impacts?

A

Decreases sweat rate and plasma volume.
- Further ↓ cardiac output, maximal oxygen uptake, muscle strength and work capacity

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14
Q

Why is prolonged HIE markedly impaired by a hot environment?

A

-Competing regulatory demands for blood flow between thermoreg, working muscle and CNS
-Heat-related changes in skeletal muscle function and metabolism

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15
Q

What is the most rapid way to lower body temp?

A

Cold water immersion

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16
Q

What is the best way of mitigating the impact of heat stress BEFORE exercise?

A

heat acclimation and aerobic training

17
Q

What is the best way of mitigating the impact of heat stress IMMEDIETELY BEFORE exercise?

A

pre-cooling, hydration status

18
Q

What is the best way of mitigating the impact of heat stress DURING exercise?

A

hydration, clothing, cooling

19
Q

What is hypothermia?

A

When core temperature drops below 35 degrees C

Heat loss > heat production

20
Q

How does cold acclimatisation work?

A

Results in lower skin temperature at which shivering begins.

Maintains higher hand + foot temp (improved peripheral blood flow).

Improved ability to sleep in the cold (due to reduced shivering)