Week 5: Fluid

Question 1

What are the key consequences of dehydration leading to impaired performance?

Answer 1

4 key factors are: Cardiovascular, Metabolic, Thermoregulation and perception/cognition.
One main linkage of dehydration and impaired performance is when plasma volume is decreased leading to impaired cardiovascular system. Another consequence is increased core temperature as there is a potential indirect link between dehydration and hyperthermia

Question 2

At what level of dehydration is said on the guidelines that there will there be detrimental effects? what should be done if sweat loss are high?

Answer 2

Dehydration should be limited to around <2% of body mass. Drinking included with sodium.

Question 3

What is Hyponatraemia? Name 3 symptoms. What is the strongest risk factor?

Answer 3

It is when there is an imbalance of sodium and water in the body. Hyponatraemia occurs at plasma sodium concentration of <135mmol/L (normally 135-146mmol/L)
Symptoms include: Weakness dizziness, headache, nausea, cerebrak iedema, altered mental function, seizures, pulmonary oedema coma, death.
The strongest risk factor is when abnormally low blood sodium concentration is reached.
People with low body mass index are likely to get hyponatraemia

Question 4

What are some of the challenged of the hypohydration “2% rule”

Answer 4

1. Research that investigated and created the hypohydration condition may have been questionable.
2. perception/individual differences. In some cases athletes may actually benefit more from hypohydrated as they become lighter, participants may alter their running knowing that they are in a hypohydrated state, or may not be enthused by knowing their hypohydrated state.
3. Type of exercise. Many tests use wingate test with a fixed intensity disregarding the ingame condition of hills and uneven land.

Question 5

How does ecological validity impact power output?

Answer 5

There is a lot of individuality in power output but overall, ecological validity bas an effect on power output.

Question 6

Should athletes follow the dehydration 2% rule?

Answer 6

Perhaps not. Evidence has indicated that Exercise induce dehydration ≤ 4% body weight may not impair endurance performance in real-world exercise conditions. Under fixed intensity exercise conditions, EID ≥ 2% is associated with a reduction in endurance capacity.

It may be recommended that athletes just hydrate themselves when they are thirsty. Body mass loss does not equal hydration change. BM can decrease by 1-3% without notable hypohydration occuring.

Question 7

which of the following may be the major source of power decrement? Exercise intensity, Exercise duration or Dehydration?

Answer 7

Exercise intensity and duration are more influential than dehydration

Question 8

which of the following may be the major source of power decrement? Exercise intensity, Exercise duration or Dehydration?

Answer 8

Exercise intensity and duration are more influential than dehydration

Question 9

Overall, which is better? drink to thirst or 2% strategy?

Answer 9

There is still debate in literature regarding these 2 strategies, where literature counter each belief. Also it depends on the situation and the individual.