LEWIS: Water & Electrolytic Balance Flashcards
Electrolytes are important for:
Vital for proper functioning of cells, particularly muscle cells
Ensuring that nutrients and waste products are exchanged
Body’s pH is maintained
Water is important for 5 functions:
- Regulates body temp
- Carries nutrients and oxygen to all cells in the body via the blood plasma
- Helps to convert food into energy and absorb nutrients
- Removes waste
- Protects and cushions vital organs
Most important electrolytes are:
Sodium
Potassium
Chlorine
Vital for the electrical transmission of nerve impulses that control muscle contractions
Any attempts to maintain water and electrolytic balances must be in relation to:
The intensity and duration of exercise
Environmental conditions
The convenience of ingesting fluids and electrolytes
Dehydration leads to:
- Thicker blood/increase in viscosity
- Increase in HR - heart has to work harder
- Less oxygen to the working muscles
- Reduced blood flow to skin/unable to maintain correct body temp
- Slows reaction time due to slow nerve impulses
- Muscle fatigue
- Muscle cramps
- Irregular heart beat
- Disruption to removal of waste products/ lactic acid builds up
Hypotonic drinks:
- Replace lost fluids but don’t give carbohydrates
- Provide extra electrolytes
- Used by jockeys and gymnasts who need to keep their weight down
Isotonic drinks:
- Sodium chloride and sugar
- Used by middle and long distance runners, games players
- Replace lost fluids and give a carbohydrate boost
Water is lost from the body through:
- expulsion of waste products
- exhaling
- sweating
amount of water lost through exhaling and sweating varies in relation to
environmental conditions (temp. humidity and altitude) amount of exercise you are undertaking
Water loss is greatest in
cold temperatures (air=dry) altitude
water loss when sweating is greatest in
high temperature
Under all environmental conditions, exercise causes more fluid loss
Produce heat as a by-product and the body must lose that heat to maintain its internal temperature within the normal range.
Exercise also raises our breathing rate and we lose more water vapour by exhaling.
Also lose electrolytes through
sweating
Dehydration has a number of detrimental effects:
- Increased blood viscosity
- Reduction in blood flow
- rise in cardiac activity to maintain flow to organs and muscles
- blood flow to skin decreases as blood volume decrease, so body cannot cool itself effectively (body temp rises)
Rises in body temperature are serious, leading to:
heat stress
collapse
death
Fluid loss can also reduce
- aerobic exercise performance
- impair reaction time, judgement and decision making
The electrolytic balance is affected by electrolyte loss through:
Swearing
Unbalanced diet
Loss of electrolytes can cause impairments to performance by causing:
- drowsiness and impaired decision making
- muscle weakness and fatigue
- muscle cramps
- interference in the neural control of the heart causing an abnormal heart rhythm
As electrolytes are dissolved in water, any change to the amount of water in the body will also change the electrolytic balance. They must be seen as Inter-related and must both be related particularly when
Exercising and in environment abnormal conditions
Any attempt to maintain water and electrolytic balances must be in relation to:
- intensity and duration of exercise
- environmental conditions
- convenience of ingesting fluids and electrolytes
As sports events can be varied. A performer should consider what they can do:
Prior
During
After
An event
Prior to an event, performers are generally advised to:
- drink 400-600ml of fluid 2-3 hours prior and then 150 to 350ml fluid about 15 min before exercise
- eat a meal/snack high in carbohydrate, 2-4 hours prior (ideally carbohydrate (whole grains), vegetables)
During the event, performers should
Ingest water, carbohydrate and electrolytes whenever possible
How much and how often during an event will depend on:
Convenience
During an event, performers must be aware of how quickly carbohydrates become available as glucose in the bloodstream. Carbohydrates with a higher glycaemic index are absorbed more quickly into the bloodstream so the performer’s choice of carbohydrate depends on whether they want:
Rapid restoration of blood sugar levels after prolonged work or a slower release of glucose into the bloodstream
After the event, performers (particularly endurance or those competing in conditions of high heat and humidity) are rarely able to keeps themselves hydrated. Several reasons:
- exercise represses thirst and performers underestimate their level of dehydration
- limited opportunities to drink during an event
- intolerance to taking on too much fluid; feelings of sickness are likely
- may be an underestimate of how much the performer is sweating
Rehydration after an event is vital, particularly if the performer is going to be competing again later in the day or next day.
The essential need is to:
Restore the water and electrolytic balance and to replenish carbohydrates
Immediately after an event an electrolytic drink will help, but then the performer should:
Revert to their normal diet, but with plenty of fluids, carbohydrates etc.
