7.2- Altitude and heat

Question 1

Definition of altitude

Answer 1

the height/ elevation of an area above sea level

Question 2

Definition of HUMIDITY

Answer 2

Humidity is the amount of water vapor in the atmospheric air

Question 3

Why must athletes prepare for differing environmental conditions

Answer 3

differing environmental conditions affect efficiency of cardiovascular, respiratory systems
- e.g uk footballers in mild wet UK conditions must acclimatise to altitiude or extremes of heat (e.g 2010 world cup in SA which was 1,200 above sea level) Also Qatar 2022 world cup was in nov and dec instead of the summer.
-this can affect performance & health of athletes by affecting the CV and respiratory systesm

Question 4

What is BAROMETRIC PRESSURE ?

Answer 4

the PRESSURE exerted by the earth’s ATMOSPHERE at any given point
As altitude increase Barometer pressure decreases

Question 5

What happens at high altitude to oxygen

Answer 5

rate of O2 diffusion decreases = reducing Hb saturation = poor O2 transportation

Question 6

What are the consequences of altitude ?

Answer 6

• breathing frequency increase (at rest + exercise)
• blood volume decreases in first few hours (plasma volume decrese by 25% due to increasing the density of red blood cells)
• SV decrease in first few housrs -> ^ HR slightly raised Q (CO)
• maximal HR, SV, Q (CO) decrease

Question 7

What is the ultimate outcome of the effects of altitude ?

Answer 7

• altitude has little affect on performance below 1,500m
• reduced aerobic capacity and VO2 Max
• increased lactic acid production
• early fatigue

coaches - supply oxygen, substitutions, increase work:relief ratio

Question 8

describe the overview of the acute effects of high altitude on the CV and respiratory systems

Answer 8

Question 9

What is ACCLIMATISATION ?

Answer 9

gradual ADAPTATION to a CHANGE in the ENVIRONMENT (for example, lower pO2 at altitude)

Question 10

how long does it take to acclimatise to altitude

Answer 10

• 3-5 days for low altitude performance (1,000 - 2,000m)
• 1-2 weeks for moderate altitude peformance (2,000 - 3,000m)

Question 11

What are the 4 benefits of acclimatisation ?

Answer 11

• release of erythropoietin -> ^ red blood cell production (peaks at 24 to 48hrs)

-breathing rate, ventilation stabilise (however still elavated at rest/exercise compared to sea level)

• SV and Q reduce as o2 extraction becomes more effcient

-altitude sickness (headache, restlessness and poor sleep) = reduced

Question 12

What is the normal body temperature ?

Answer 12

37oC

Question 13

What is THERMOREGULATION ?

Answer 13

process of MAINTAINING internal core temperature

Question 14

What are THERMORECEPTORS ?

Answer 14

SENSORY RECEPTORS which sense a CHANGE in temperature and RELAY information to the brain

Question 15

What is DEHYDRATION ?

Answer 15

loss of WATER in BODY TISSUE, largely caused by SWEATING

Question 16

What happens when you exercise in heat?

Answer 16

affects performance, disrupt scheduling, serious consequences to health of an athlete or spectator.
e.g Qatar

Question 17

What happens when core temp rises ?

Answer 17

metabolic heat is transported by CIRCULATING BLOOD to the surface of the skin for EVAPORATION (sweat)

Question 18

How does low humidity affect sweating ?

Answer 18

increases sweating

Question 19

Why is sweating beneficial for the body when hot?

Answer 19

-has cooling effect on body

-it removes excess heat quickly

Question 20

How does high humidity affect sweating ?

Answer 20

decreases sweating

Question 21

What is HYPERTHERMIA ? (not hypo)

Answer 21

significantly raised core body temperature

Question 22

What are the 3 causes of raised body temp ?

Answer 22

• high and prolonged intensity
• high air temps
• high relative humidity
• (can happen when athlete pushes themselves for too long or when its too hot)

Question 23

What causes cardiovascular drift ?

Answer 23

prolonged exercise in heat -> ^ rate of muscular contraction -> metabolic heat -> it not removed quick enough to maintain core temp

Question 24

What is CARDIOVASCULAR DRIFT ?

Answer 24

upward drift in HR during SUSTAINED steady-state activity

-associated with rise in body temp

Question 25

What are the effects of heat, humidity and the body’s thermolatory response on the cardiovascular system ?

Answer 25

• dilation of arterioles, capillaries -> ^ blood flow & blood pooling in the limbs
• decreased blood volume, venous return, SV, Q, blood pressure -> ^ HR, reduced O2 to muscles, ^ strain on CV system

Question 26

What are the effect of heat on the respiratory system ?

Answer 26

• dehydration, drying of airways (above 32 degrees) -> difficulty breathing -> ^ mucus production, constriction of airways, decrease vol of air for gaseous exchange

-^ breathing freq to maintain o2 consumption -> ^ oxygen cost of exercise
- high levels of sunshine lead pollution in the air lead to coughing and wheezing or asthma symptoms

Question 27

How are sports are not affected by hyperthermia?

Answer 27

• maximal strength production - sprinting, throwing and jumping
• endurance are affected

Question 28

Name 2 pre-competition strategies to maximise performance in heat and humidity

Answer 28

-7-14 days acclimatisation in same conditions to ^ bodys tolerance to heat (by ^ plasma volume, decrease electrolytes, decrease heart rate at given pace and temp)

-using cooling aids to reduce core temp & delay effects of dehydration e.g ice vests

Question 29

Name 3 during competition strategies to maximise performance in heat and humidity

Answer 29

-pacing strategies

-wearing suitable clothing to maximise heat loss

-rehydrating as much as possible -> hypotonic, isotonic drinks

Question 30

Name 3 post competition strategies to maximise performance in heat and humidity

Answer 30

-cooling aids -> fans, cold towels, light weight compression wear

-rehydrating to replace lost fluids -> isotonic solution

Question 31

Explain an overview of the effects of altitude on the cardiovascular & respiratory systems

Answer 31

as altitude ^ -> barometric pressure decreases

this has a negative impact on the oxygen diffusion gradient

-> reduces haemoglobin saturation -> poor transport of O2

-> causes:

blood vol to decrease
stroke vol decreases
cardiac output decreases
HR decreases

this reduces aerobic capacity, VO2 max -> impacting intensity & duration of performance