7.2- Altitude and heat Flashcards
Definition of altitude
the height/ elevation of an area above sea level
Why must athletes prepare for differing environmental conditions
differing environmental conditions affect efficiency of cardiovascular, respiratory systems
-this can affect performance & health of athletes
What is BAROMETRIC PRESSURE ?
the PRESSURE exerted by the earth’s ATMOSPHERE at any given point
What happens at high altitude to oxygen
rate of O2 diffusion decreases = reducing Hb saturation = poor O2 transportation
What are the consequences of altitude ?
- breathing frequency increase
- blood volume decreases
- SV decrease -> ^ HR
- maximal HR, SV, Q decrease
What is the ultimate outcome of the effects of altitude ?
- reduced aerobic capacity and VO2 Max
- increased lactic acid production
- early fatigue
What is ACCLIMATISATION ?
gradual ADAPTATION to a CHANGE in the ENVIRONMENT
What are the 4 benefits of acclimatisation ?
- release of erythropoietin -> ^ red blood cell production
-breathing rate, ventilation stabilise
- SV and Q reduce
-altitude sickness = reduced
What is the normal body temperature ?
37oC
What is THERMOREGULATION ?
process of MAINTAINING internal core temperature
What are THERMORECEPTORS ?
SENSORY RECEPTORS which sense a CHANGE in temperature and RELAY information to the brain
What is DEHYDRATION ?
loss of WATER in BODY TISSUE, largely caused by SWEATING
What happens when core temp rises ?
metabolic heat is transported by CIRCULATING BLOOD to the surface of the skin for EVAPORATION (sweat)
How does low humidity affect sweating ?
increases sweating
Why is sweating beneficial for the body when hot?
-has cooling effect on body
-it removes excess heat quickly
How does high humidity affect sweating ?
decreases sweating
What is HYPERTHERMIA ?
significantly raised core body temperature
What are the 3 causes of raised body temp ?
- high and prolonged intensity
- high air temps
- high relative humidity
What causes cardiovascular drift ?
prolonged exercise in heat -> ^ rate of muscular contraction -> metabolic heat -> it not removed quick enough to maintain core temp
What is CARDIOVASCULAR DRIFT ?
upward drift in HR during SUSTAINED steady-state activity
-associated with rise in body temp
What are the effects of heat on the cardiovascular system ?
- dilation of arterioles, capillaries -> ^ blood flow & pooling in the limbs
- decreased blood volume, venous return, SV, Q, blood pressure -> ^ HR, reduced O2 to muscles, ^ strain on CV system
What are the effect of heat on the respiratory system ?
- dehydration, drying of airways -> difficulty breathing -> ^ mucus production, constriction of airways
-^ breathing freq to maintain o2 consumption -> ^ oxygen cost of exercise
Name 2 pre-competition strategies to maximise performance in heat and humidity
-7-14 days acclimatisation in same conditions to ^ bodys tolerance to heat
-using cooling aids to reduce core temp & delay effects of dehydration
Name 3 during competition strategies to maximise performance in heat and humidity
-pacing strategies
-wearing suitable clothing to maximise heat loss
-rehydrating as much as possible -> hypertonic, isotonic drinks
Name 3 post competition strategies to maximise performance in heat and humidity
-cooling aids -> fans
-rehydrating to replace lost fluids -> isotonic, hypertonic
Explain an overview of the effects of altitude on the cardiovascular & respiratory systems
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
