hydration

Question 1

function of aquaporin

Answer 1

transport water across cell membranes in response to osmotic gradients created by active solute transport

Question 2

total body water equation

Answer 2

0.6 x body weight as water is 60% of our body weight

Question 3

dehydration clinical threshold

Answer 3

no more than 2% dehydration as it leads to a 10% in performance

Question 4

how is water distributed

Answer 4

by compartments- Movement of water between the compartments influenced by (i) hydrostatic pressure and (ii) osmotic pressure of the plasma proteins

Question 5

what is hydrostatic pressure

Answer 5

pressure exerted by a fluid (liquid or gas) at rest due to the force of gravity acting on the fluid’s weight.

Question 6

what is thermoregulation

Answer 6

a mechanism by which mammals maintain body temperature with tightly controlled self-regulation independent of external temperatures. Temperature regulation is a type of homeostasis and a means of preserving a stable internal temperature in order to survive

Question 7

what does fluid loss cause

Answer 7

reduce circulating blood/plasma volume, increased cardiovascular strain, increased glycogen depletion, reduced ability to regulate body temperature (hyperthermia), central fatigue.

Question 8

sweat rates

Answer 8

vary from individual and conditions

Question 9

warm environment

Answer 9

If temp greater than body temperature- can’t lose heat via radiation/convection and reduced ability to lose heat via sweat in humid conditions
Heat illness
Heat exhaustion
Heat stroke
Those with long events or those who are required to wear heavy clothing at risk
NB acclimatisation, individualised athlete hydration plans, consumption of cooled fluids during exercise, consider electrolyte sources during exercise, ensure euhydration prior to exercise

Question 10

cold environment

Answer 10

Energy requirements (CHO) increased- need it to maintain core temperature
Risk of hypohydration because of increased diuresis, reduced thirst sensation and altered urge to drink, sweat losses from increased clothing, increased respiration (at altitude)
However, relative to the heat, dehydration of 2-3% will have less of a detrimental effect on performance vs same losses in heat

Question 11

restoring fluids nb

Answer 11

Restoring fluids maintains normal muscle function, helps prevent a decrease in physical performance and reduces the risk of heat stress.

Question 12

clinical level of assessing dehydration

Answer 12

• Monitor intake/losses (e.g. urinary output)
• Appearance of skin, mucous membranes
• Laboratory tests- bloods (can measure specific electrolytes also) urine etc.

Question 13

field level

Answer 13

-Athlete reports of intake/losses
-Pre and post-event weighing of athlete to monitor losses
- Sweat rate
- Urinary colour

Question 14

euhdydration

Answer 14

optimal or normal hydration

Question 15

overhydration aka hyponatremia

Answer 15

overhydration= excessive intake of water that dilutes the levels of sodium in the blood
Sodium is an essential electrolyte that helps regulate the balance of fluids in and around cells. When sodium levels become dangerously low due to overhydration, it can lead to hyponatremia, which can have serious health consequences.

Question 16

Refractometer

Answer 16

to measure urine specific gravity

Question 17

hypohydration

Answer 17

is when the body doesn’t receive enough water to compensate for the fluid losses it experiences during various activities

Question 18

hypohydration symptoms

Answer 18

increased core body temperature,
decreased blood pressure (hypotension),
decreased sweat rate, rapid breathing, fast heartbeat, dizziness or light-headedness,
irritability, confusion, delirium,
lack of urination,
sunken eyes,
shock,
unconsciousness,
dry, wrinkled skin that doesn’t “bounce back” quickly when pitched,
reduced stroke volume and cardiac output,
reduced blood flow to muscles

Question 19

rhabdomyolysis

Answer 19

rapid breakdown of skeletal muscle tissue, causing the release of muscle cell contents into the bloodstream.

Question 20

factors affecting during exercise hydration

Answer 20

Rules and format of sport
Athlete preferences- most athletes may tolerate 200-300mls every 15 mins, but this will vary (AIS, 2009)
Temperature of the drink – may further improve performance in heat by reduction in core temperature
Formulation of the drink – i.e. inclusion of CHO in drink as a further ergogenic aid.
Electrolyte composition of the drink
Hydration also a concern for athletes in wet environments and air-conditioned stadiums

Question 21

post exercise hydration needs

Answer 21

Will need water/fluid and sodium source to minimise urinary losses
Sodium- helps to retain fluids
For effective rehydration, need to consume greater amount of fluids than lost

Question 22

Hyponatremia

Answer 22

is the reduction of the sodium concentration in the blood
(< 135 mmol/l)