Fatigue

Question 1

What happens during dehydration?

Answer 1

1) water is lost through sweat as the core body temp rises
2) blood viscosity increases, blood pressure decreases, blood flow decreases, loss of electrolytes
3) body stops sweating to reduce further water loss
4) heart needs to work harder to maintain the same o2 demands
5) increase in body temp as there’s more exothermic reactions
6) performer can’t meet the demands of the activity

Question 2

What happens during thermoregulation?

Answer 2

1) during exercise the body’s temp will rise from exothermic reactions and muscle contractions
2) water is lost causing increase in blood viscosity
3) sweating stops to reduce water loss
4) to continue to cool thermeoreceptors detect the increase in temp and send signals to the hypothalamus (in medulla oblongata)
5) this triggers vasodilation (opening and widening of blood vessels to redirect the blood at surface of skin to cool in 4 different ways)
6) as this happens the amount of blood and o2 is restricted to the working muscles so this causes fatigue

Question 3

What is the overall summary of dehydration and thermoregulation?

Answer 3

D= core body temp rises 
T = reduced o2 supply to the working muscles

Question 4

What happens during lactic acid build up?

Answer 4

• Latic acid turns into lactate and hydrogen ions
• H ions makes the muscle acidic
• acidic environment denatures enzymes to restrict ATP resynthesis

Question 5

What are the 4 ways the body can cool during thermoregulation?

Answer 5

• Radiation (heat moves from hot to cold)
• evaporation ( sweat glands open to release water and electrolytes and allow the heat to disperse as vapour)
• convection (cool air passing the skin taking away the heat
• conduction (losing heat through physical contact of an object cooler than body temp)

Question 6

Why can’t heat be lost in warm and humid conditions?

Answer 6

The environment is hotter than body temp so radiation can’t take place

Question 7

What occurs to the body during cold conditions?

Answer 7

1) vasoconstriction (redirecting of blood towards the core to preserve heat)
2) heat retention (hairs raised/shivering - muscle contractions and exothermic reactions)

Question 8

What are some of the causes of fatigue?

Answer 8

• glycogen depletion (hitting the wall)
• lactic acid build up
• dehydration
• thermoregulation
• reduce rate of ATP resynthesis
• reduced levels of acetylcholine ( neurotransmitter for muscle contraction)