Lecture 18

Question 1

most important defence against heat injury

Answer 1

behavioural thermoregulation

also sweating is physiological mechanism

Question 2

4 things that limit performance under heat stress

Answer 2

• critical body core temperature
• cardiovascular strain
• psychophysical strain
• metabolic strain

Question 3

2 things affecting cardiovascular strain when exercising during the heat

Answer 3

different to normal temperature

• decreased blood pressure
• decreased blood flow to several tissues and organs
• decreased blood flow to skin, muscle and brain

Question 4

what is the psychophysical strain of exercising in the heat

Answer 4

• increased perceived exertion

Question 5

what is the metabolic strain of exercising in the heat

Answer 5

muscle glycogen depletion

Question 6

what are the 5 major personal factors governing performance in the heat

Answer 6

1. aerobic fitness
2. heat acclimatisation
3. initial physiological status
4. recent illness
5. hydration

Question 7

what is the difference between heat acclimation and heat acclimatisation

Answer 7

acclimation = artificial, periodic exposure

acclimatisation = go to a warm place and naturally adapt to it

Question 8

what processes does hypohydration (low body water) impair

Answer 8

• cardiovascular function
• sweat production
• cognition

Question 9

how long should you allow for optimal acclimatisation

Answer 9

around 2 weeks

Question 10

what is meant by hypo-hydration can wipe out the benefits of short term increase in fitness or acclimation

Answer 10

if you are dehydrated you are less able to tolerate the heat

Question 11

5 other personal factors affecting performance in the heat

Answer 11

• medications
• body size
• age
• sex
• fatigue and sleep deprivation

Question 12

how can age affect performance in the heat

Answer 12

mainly due to impaired cardiovascular response

• less behavioural capacity for young and older are less fit

Question 13

is there such thing as sun stroke

Answer 13

no

Question 14

how does sunburn effect the bodies ability to perform

Answer 14

• impairs sweat and skin blood flow responses
• tattoos do the same

Question 15

what is heat syncope

Answer 15

fainting

Question 16

what is the main feature and cause of heat syncope

Answer 16

main feature : especially if 1st day of exercise in the heat

cause : inadequate vasoconstriction and HR response to maintain blood pressure

Question 17

why is heat exhaustion considered to be “less bad”

Answer 17

because it tends to prevent you from being active enough to get heat stroke

Question 18

what is the main feature and cause of heat exhaustion

Answer 18

main feature : exhaustion, hot, flushed, sweaty, rapid HR

cause : homeostatic capacity exceeded, especially the cardiovascular system

Question 19

what is the main feature and cause of exertional heat stroke

Answer 19

mai feature : complete exhaustion with central nervous system disturbance

cause : major cellular disturbances, mainly due to increased body temperature

Question 20

what is the fastest way to cool someone down

Answer 20

immersion in cool or cold water

Question 21

what can be dangerous with highly motivated, recreationally fit athletes exercising in the heat

Answer 21

they are competitive but dont have the high levels of fitness to deal with it

Question 22

why can intense practice sessions have high heat strains for individuals

Answer 22

• early in summer
• unseasonally warm
• least fit people in team training drills
• protective clothing

Question 23

5 strategies to decrease heat strain and increase heat performance

Answer 23

• increase aerobic fitness and heat acclimatisation
• decrease clothing and carried weight
• decrease exercise volume
• optimise plasma volume and osmolality
• artificial cooling

Question 24

how could you decrease the exercise volume to decrease heat strain and increase heat performance

Answer 24

• shorten warm up
• decrease intensity
• decrease work to rest cycle