Phys. Ex. Environment and Performance

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1

4 Types of environments in which performance can take place

exercise in heat

exercise in cold

low pressure environment (altitude)

high pressure environment (under sea)

2

Which environment do we know most/least about?

heat - most

under sea - least

3

In the heat environment, the ability to exercise is dependent on (physiological and behavioral)

P - increase heat dissipation

B - decrease artificial insulation

4

In the cold environment, the ability to exercise is dependent on (physiological and behavioral)

P - increase heat production and storage

B - increase artificial insulation

5

________ is the air layer that exists between your skin and the first layer of clothing

microenvironment

6

What is the goal of regulating the microenvironment?

Thermal balance

7

What is thermal balance?

heat production = heat dissipation

8

_______ thermal balance is when dissipation occurs more than production

negative

9

________ thermal balance is when production of heat is more than dissipation

positive

10

Normal body temperature range

36.5-37.5 degrees C

11

What classification of animals are we?

homeotherms

12

_____________ are animals that regulate its core temperature independent of the environmental temperature

homeotherms

13

___________- is an animal whose body temperature becomes the temperature of the environment

poikilotherm/ectotherm

14

Why is our ability to regulate temperature not perfect? (3)

Circadian rhythm

Phases of menstrual cycle

How to measure temperature

15

What is circadian rhythm?

cycle that repeats itself over 10-24 hours.

Temperature changes based on the time of day

16

When is your body temperature lowest?

When you first get out of bed, because all night metabolic rate is low as it can be, generating less heat

17

When is your body temperature highest?

After the evening meal, because during the day the temperature goes up and increases metabolic rate

18

2 phases of the menstrual cycle

Falicular

Ludial

19

Which phase of the menstrual cycle is the first 14?

falicular

20

Which phase of menstrual cycle makes body temperature higher?

Ludial

21

Ludial phase temperature is ___-___ degrees C higher than falicular.

0.5-1.0

22

When do you run the risk of heat related issues more often? Why?

ludial because temperature is closer to critical temperature due to hormonal control

23

What is the worst way to measure body temperature?

sticking thermometer in the mouth

24

Why do we want to regulate temperature so accurately? (3)

Action of nervous system - fast neural communication

Cellular metabolism - enzymes temperature dependent

Myocardial function - change efficiency

25

What is core temperature?

the central region of the body temperature

26

What is peripheral temperature?

surface temperature

27

5 ways to measure core temperature

Orally

Rectally

Tympanically

Esophageal

Telemetry system

28

How to measure temperature orally

Put thermometer under tongue

29

Why is it bad to find temperature orally?

temperature changes with every breath they take

30

What is the most common way to represent temperature in newborn babies?

rectal

31

What is the most accurate representation of core temperature before telemetry?

rectal

32

How is core temperature measured tympanically?

  • radioactive chip in ear, push it in next to tympanic membrane, then hold radioactive receiver reading temperature of the brain area (not necessarily core temperature)
33

How is core temperature measured esophageal?

put someone on their back, put thermoster up their nose, follow nasal passages, comes back and feel it hanging in the back of their throat, they swallow hard until it goes down to a level of the atria. Wire hanging from nose goes into a telethermometer and gives you a core temperature.

34

How does the telemetry system work?

pill has a magnetic bar attached to it, when magnetic bar is taken off it’s activated, taken with 250mL water 2-4 hours before subject/exercise, travels through digestive system, and someone carries a small box, put it next to their back, and have core temperature in seconds.

35

What is the problem with telemetry systems?

each pill costs $60 and box is $2500

36

What is core-shell-environment gradient?

move heat form core to shell to environment direction

37

What does shell stand for?

peripheral temperature

38

What is Tsk?

mean temperature of the skin (peripheral temperature)

39

Surface thermostesr are placed on 4 locations and numbered:

Clavical (T2)

Bicep (T3)

Thigh (T4)

Calf (T5)

40

What is T1?

Core temperature

41

Other symbols for T1 (3)

Tc

Te

Tr

42

Tsk = ?

0.3(T2 + T3) + 0.2(T4 + T5)

43

Tb means what?

mean temperature of the body

44

Tb = ?

0.67(T1) + 0.33 (Tsk)

45

Exercise in heat creates a situation of POSITIVE/NEGATIVE heat balance

positive

46

Physiological factors that may be impacted upon by exericse in the heat (4)

Maximal oxygen consumption

Cardiovascular function

Fluid shifts

Electrlyte balance

47

During brief exercise, max VO2 doesn't fall with short duration exercise unless body temperature rises above ____ degrees C

40

48

Why would Vo2 drop in heat environment?

shift of blood from working tissues to the skin

49

why would Q reduce in heat environent?

reduction in stroke volume

50

After an hhour or more of exercise in heat, a more consistent drop in max VO2 may occur, __-__%

3-8

51

Why does cardiac output often rise in short duration exercise and long duration mild exericse?

increase in HR, because SV is diminished in heat

directed towards skin for dissipation

52

Individuals who exercise in the heat for prolonged times can lose more than ___ liters of body fluids per hour, and experience a total weight loss of ___-___% of the total body weight in the course of an endurance event

2

7-8

53

What happens when blood volume is reduced in heat environment?

Reduce Q, reduce BP

Reduce sweat capacity --> increase temperature

54

_________ the sum total of the physiological adjustments that occur as a result of repeated exposures to hot environments

acclimation/acclimatization

55

______ occurs in natural setting

acclimatization

56

_____ occurs in artificial setting

acclimation

57

5 primary physiological adjustments of acclimatization to heat

1. increased peripheral conductance
2. increased plasma volume
3. increases sweating capacity
4. a fall in the threshold of skin temperature for the onset of sweating
5. better distribution of sweat over the skin

58

Physiological specifics in adjustments of acclimatization (3)

1. blood flow to the skin decreases - this restores the central blood volume
2. restoring central blood volume is important for maintaining stroke volume and muscle blood flow during the exercise.
3. this is accompanied by a large increase in sweating and evaporative cooling capacity resulting in greater peripheral conductance of heat.

59

There is a ____% increase in PV during acclimatization

12

60

There is almost a threefold increase in sweating capacity during acclimatization - __-__L per hour

1.5-4

61

Heat production in cold environments can increase ___ fold

20

62

When exercising in the cold, two important concepts must be understood

1. Skin temperature is dependent in a large measure upon the temperature of the air or water surrounding the skin and is relatively independent of the exercise load.

2. Any change in core temperature is independent of the ambient temperature and is primarily dependent upon the relative exercise load.

63

What maximal Vo2 and oxygen cost of submaximal exercise effected by cold?

No, provided it's enough to maintain core temperature

64

Oxygen cost of submaximal exercise by subjects in wet clothing exercising in wind is __-__% higher than same exercise in comfortable environment

15-20

65

Why is there an increased oxygen cost in wet cold weather?

shivering response

66

2 effects of shivering

1. An increase of muscle tome with a periodic simultaneous contraction of the agonists and antagonists.
2. Causes an increase in metabolic rate, thus an increase in heat production.

67

5 Circulatory adjustments during cold exposure

1. cutaneous vasoconstriction
2. increase in peripheral vascular resistance
3. increase in systemic blood pressure
4. increase in afterload
5. Lewis-Hunting Response - vasoconstriction followed by bouts of vasodilation.

68

What is the lewis-hunting response?

vasoconstriction followed by bouts of vasodilation

69

TVO2

thermoregulatory oxygen consumption

70

What is the difference in the VO2 between the cold environment and the neutral environment for the same activity called?

Thermoregulatory oxygen consumption

71

2 Causes of TVO2

1. chemical heat production - non-shivering thermoregulation - NST

2. Shivering

72

NST?

Non-shivering thermoregulation

73

What do you use to dissipate heat?

heat sink

74

4 avenues of dissipation (or heat sinks) to maintain core temperature

radiation

Conduction

convection

evaporation

75

________ is the transfer of heat using inferred rays

radiation

76

At rest, we dissipate heat via radiation ___% of the time

70

77

___________ is the transfer of heat from a warmed object to a cooler object but must have physical contract

conduction

78

Dissipation of heat via conduction is used ___% of the time

3

79

______ is the transfer of heat to either air or eater provided that the air or water is moving

convection

80

Dissipation of heat via convection is used ____% of the time

whatever is left (12%)

81

_________ can only work if the moisture on your skin evaporates into the air

evaporation

82

In order for water to evaporate, you are required to convert water into a gaseous form using energy, called _________________

latent heat of vaporization

83

What 3 types of dissipation can also be heat sources?

radiation

conductiong

convection

84

What type of dissipation can NOT be used as a heat source?

evaporation

85

If air is already saturated with moisture, it can still accept moisture from your skin. T/F

False, cannot

86

Dissipation of heat via evaporation occurs ___% of the time

25

87

What is our only viable heat source?

metabolic rate

88

3 ways to generate heat

shivering

chemical heat production

voluntary exercise

89

_______ is a series of microvibrations, contractions and relaxation of antagonist and agonist muscles

shivering

90

What are the chemical activities of body organs?

Chemical heat production

91

Where is the temperature control center regulated?

hypothalamus in the midbrain

92

Where is the hypothalamus located?

midbrain

93

2 parts of the hypothalamus

anterior

posterior

94

Which part of the hypothalamus responds to a heat environment?

anterior

95

What part of the hypothalamus decides when you should start to sweat basd on temperature of blood?

anterior

96

What part of the hypothalamus responds to a cold environment?

posterior

97

What part of the hypothalamus regulates heat conservation events?

posterior

98

What heat conservation events does the posterior hypothalamus take place in? (2)

production of heat

Increase metabolic rate

99

2 ways to conserve heat

vasodilation

vasoconstriction

100

For heat, we VASOCONSTRICT/VASODILATE and cause what?

vasodilate

heat dissipation

101

How does vasodilation cause heat dissipation?

brings blood to the surface and the amount of insulation naturally is going to go down

102

For cold, we VASOCONTRICT/VASODILATE and cause what?

vasoconstrict

heat production and conservation

103

How does vasoconstriction cause heat production and conservation?

Constricts everything and keeps blood in the periphery and makes it harder to dissipate.

104

When considering the mechanisms of heat transfer - they can only occur due to two physiological occurrences:

  1. body can change surface temperature by altering skin blood flow
  2. body can control sweat secretion via the sweat glands
105

Human skin, regardless of color, absorbs about ___% of the radiant energy that strikes it

97

106

The temperature of an object is a measure of what?

Kinetic activity of its molecules

107

_________ occurs when body temperature rises above 40 degrees C due to lack of evaporative cooling

heat stroke

108

5 Characteristics of heat exhaustion

Rapid weak pulse

Hypotension

faintness

profuse sweating

Psychological disorientation

109

4 Types of thermal distress or illness

dehydration

heat cramps

heat exhaustion

heat stroke

110

_____ is loss of body fluids

dehydration

111

_______ is involuntary cramping of skeletal muscle

heat cramps

112

_______ is characterized by hypotension - weakness caused by inability of the circulation to compensate for teh vasofilation of the peripheral vessels

heat exhaustion

113

______ is the complete failure of the hypothalamus

heat stroke