Effect of an isotonic rehydration sports drink
Nicholas Cheong
consumption of isotonic drinks such as 100 plus helps restore body fluid volume.
Are we looking at isotonic, hypotonic or hypertonic rehydration here?
Surin
Edited by Nicholas
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Dear Surin,
I will try to answer your question in the context of an individual who is exercising.
During exercise, there is a rise in sympathetic outflow to the sweat glands.
Consequently, the glands start to secrete fluid which we know as sweat. The fluids
do not contain merely water. They contain a substantial proportion of electrolytes like
chloride, sodium, potassium and so forth.
If I am not wrong, an exercising individual normally experiences isotonic dehydration.
This means almost equal proportion of electrolytes and water are lost through sweat.
The best way to reverse this condition is by drinking an isotonic beverage.
What this isotonic drink does is return the body fluid volume back to normal while
maintaining osmotic equilibrium between intracellular and extracellular fluids.
I have very little knowledge about what you asked. Let's wait for Dr Prakash's reply.
Your friends and other members of this forum would probably like to have a go at
this question too.In the mean time, please feel free to disagree with me. It'd be
part of the learning process for all of us.
Cheers!
Humbly,
Nicholas Cheong
Batch 14 (Year 2) MBBS
Waye Young
Dear Surin,
Isotonic drinks like 100PLUS consists of two fundamental substances which are:
1. Carbohydrate (for fuel)
2. Electrolytes (especially sodium)
During normal exercise, one tends to lose more water than electrolytes (Hypertonic dehydration).
Normal Sodium concentration in ECF: 140 mmol/L
Average Sodium concentration in swea 20-60 mmol/L
( Only in extremely long distance races do the sodium loss become much more significant –e.g. about 30% of ‘Hawaiian Ironman’ finishers were hyponatremic and dehydrated. http://tinyurl.com/28972l5) Implying that unless you’re going for a long race, water should be fine for hydration.
So anyways, I believe when you ingest an isotonic drink, you’re administering an isotonic solution – which then acts as a ‘dialytic fluid’ (as in the principle of dialysis) which then brings about restoring the normal plasma osmolarity (through diffusion as well as co-transport through Na-glucose channels). In addition, the fluid consumed would be absorbed to restore fluid balance back to the state of euvolemia (normal body fluid volume) ; regulated by the kidneys.
I’m unclear whether this is called isotonic rehydration.
If there are corrections to be made; please do not hesitate to correct them.
Thanks,
Waye Young
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02:34:00
E.S.Prakash
Hello. My name is Surin. I would like to know how consumption of isotonic drinks such as 100 plus helps restore body fluid volume. We looking at isotonic, hypotonic or hypertonic rehydration here?
E.S.Prakash
have noted correctly that human sweat is typically hypotonic.
ESP
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On Sep 6, 8:59 am, "E.S.Prakash" <dresprak...@gmail.com> wrote:
> Surin: I do not have a 100 PLUS bottle at home right now; I can't seem to
> find the composition on the 100 PLUS website. Can you or someone let me know
> its composition? I once looked for it and I suspect this solution is not
> actually isotonic - that's just for marketing. It is an energy drink and may
> be hypotonic. Anyway, if the composition is known, we can work it out.
>
> Nicholas: While considerable amount of Na and Cl is lost when one sweats
>
> ESP
> ***********
>
> On Sun, Sep 5, 2010 at 10:22 PM, Nicholas Cheong <nicholascheon...@gmail.com
E.S.Prakash
100 PLUS Minuman Isotonik is said to contain a total of 6.8 g of
sucrose (molar mass 342 g) in 100 ml of the drink; the concentration
of electrolytes is not mentioned however and if we assume it is
negligible, the molarity of the solution is 200 mM. However, since
sucrose gets digested in the intestine to 2 osmoles, the osmolality
would effectively be 400 mOsm/Kg H2O. Thus, "100 PLUS Minuman
Isotonik" is actually a hyperosmotic solution, and now I understand
why I sometimes remain somewhat thirsty after gulping it.
However, I think it unlikely that it will induce significant changes
in steady state osmolality of plasma in otherwise healthy individuals
if one consumed small quantities (i.e. up to 500 ml) as changes in
osmolality of plasma would not be as rapid and the kidneys would
adjust water excretion appropriately.
It is primarily an "energy drink", and an adjunct to other solutions
such as the Oral Rehydration Solution as far as rehydration is
concerned.
Prakash
*****************
> find the composition on the 100 PLUS website. Can you or someone let me know
> its composition? I once looked for it and I suspect this solution is not
> actually isotonic - that's just for marketing. It is an energy drink and may
> be hypotonic. Anyway, if the composition is known, we can work it out.
>
> Nicholas: While considerable amount of Na and Cl is lost when one sweats
>
> ESP
> ***********
>
> On Sun, Sep 5, 2010 at 10:22 PM, Nicholas Cheong <nicholascheon...@gmail.com