Environmental Challenges

Question 1

Environmental Challenges

Answer 1

Heat, Cold, Altitude

Question 2

Heat stress

Answer 2

inability to dissipate excess heat (heat/humidity block dissipation ability)

Question 3

Thermoregulation

Answer 3

ability of body to maintain constant internal temp

Question 4

Thermoregulation cont.

Answer 4

-receptors in periphery and CNS detect temp changes
-Periphery
-CNS
=hypothalamus, Brain stem, Spinal cord (receive signal)

Question 5

Factors determining thermoregulatory stress

Answer 5

• ambient temp
• relative humidity
• wind speed

Question 6

Humitidy

Answer 6

• % of water vapor held in air
• affects perception of thermal stress
• Higher humidity limits evaporation (sweat)

Question 7

Convection

Answer 7

air blows over surface of skin

Question 8

conduction

Answer 8

physical contact between 2 or more surfaces

Question 9

radiation

Answer 9

molecules in motion emit electromagnetic waves

most heat loss during rest

Question 10

Evaporation

Answer 10

water on skin turns to vapor

Question 11

Evaporation cont

Answer 11

-accounts for 80 % of heat lost during exercise, 20 % at rest

Question 12

Circulatory and Metabolic Responses to Heat Stress

Answer 12

• ^ HR and CO
• Circulatory flow to peripheries to dissipate heat/Cool Blood
• Reddens Skin

Question 13

CMRTHS Cont.

Answer 13

• body temp increases
• oxygen uptake increases
• glycogen depletion is hastened
• muscle lactate levels increase

Question 14

Body Fluid

Answer 14

• sweating increases
• blood volume decreases
• loss of electrolytes
• release of aldosterone and ADH

Question 15

Electrolyte concentrations

Answer 15

-sodium, chloride, concentrations in sweat are lower in trained athletes. EXCEPT POTASSIUM

Question 16

Body comp. and Fitness level

Answer 16

• harder for fatties to dissipate heat

- greater CO=improves ability to dissipate heat

Question 17

Heat Cramps

Answer 17

• dehydration
• electrolyte imbalances
• sodium deficit
• neuromuscular fatigue
• painful, involuntary muscle contractions

Question 18

Syncope

Answer 18

Fainting, dizziness or lightheadedness

• excessive peripheral dilation
• pooling of blood in legs
• dehydration
• reduction in CO
• brain ischemia

Question 19

Heat Exhuastion

Answer 19

-heavy sweating
-dehydration
-sodium loss
-energy depletion
confused with heat stroke

Question 20

Heat Stroke

Answer 20

• medical emergency
• failure to dissipate heat
• thermoregulatory center is overwhelmed
• temp ^ 104 F/ 108 F ya dead
• Cellular damage to organs and tissues
• rapid cooling of body is needed

Question 21

Bulb things

Answer 21

• dry bulb=air temp
• wet bulb=temp as water evaps from it
• black globe=absorbs radiated heat

Question 22

Mean body temp

Answer 22

mean body temp of skin and core temp

Question 23

Time course of adaptations

Answer 23

Cardio=1-5 days
Temp reg=5-8
Cons. of sodium chloride=3-9
all adaptations=up to 14 days

Question 24

Acclimation vs. acclimatization

Answer 24

1. adaptation to artificial environment

2. natural environment

Question 25

Adaptations that occur

Answer 25

- lower core temp at onset of sweating - increased heat loss via radiation and convection - increased plasma volume - decreased HR - decreased body core temp - decreased oxygen consumption - exercise economy improved

Question 26

Cold Stress/Receptors

Answer 26

- monitor change and rate of decrease in temp - signal many different actions to occur - fewer amount than heat receptors - skin, abdominal viscera, and spinal cord

Question 27

Hypothermia

Answer 27

- body temp 1-2 C below normal - body temp 2-4 C below - body temp below 32 C=death

Question 28

Cold responses

Answer 28

- reductions in neuromuscular activity - reduction in force production - reduction in nerve conduction velocity - decreased heart rate - decreased time to peak power - bronchoconstriction in those with asthma

Question 29

Physiological adaptations to cold

Answer 29

- vasodilation | - higher BMR

Question 30

Altitude Stress

Answer 30

- 700 m (2300 ft) - 1524 m (5000 ft) - 2200 m (7217

Question 31

Hypoxia

Answer 31

- compromised delivery of oxygen to target tissues - decrease in barometric pressure - reduced partial pressure of O

Question 32

Responses to altitude

Answer 32

- increased resting HR - increased BP - increased pulmonary ventilation - increased depth and rate of breathing - decreased maximal O consumption - increase in hemoglobin and hematocrit blood concentrations - increased blood lactate concentrations

Question 33

Acute altitude exposure

Answer 33

- respiratory water losses - increased urine production - increased hematocrit

Question 34

Chronic altitude exposure

Answer 34

- release of epo from kidney to stimulate RBC production | - increased blood volume compensates for lower PO2

Question 35

Cardiac Output for altitude exposure

Answer 35

- CO increased at rest and during submaximal ex. - decreased stroke volume, increased HR - peaks after 6-10 days at altitude - decrease in maximal stroke volume and maximal HR

Question 36

Short vs Long duration

Answer 36

- short duration not really affected | - endurance running is affected (speed)

Question 37

Optimal alt. performance

Answer 37

- compete within 24 hours - train at 1,500 to 3,000 m above for min of two weeks - increase VO2 max at sea level to be able to compete at a lower relative intensity

Question 38

Alt. Sickness

Answer 38

- caused by reduction in partial pressure of oxygen | - can lead to, pulmonary edema, cerebral edema

Question 39

Short term alt. adapts

Answer 39

- pulmonary ventilation - release of EPO - hemoglobin - hematocrit - plasma volume

Question 40

Long term alt. adapts

Answer 40

- Mito. and cap density - pulmonary diffusing - mito enzymes increase - resp. chain enzymes increase - cardiac output increase