electrolyte replacement

warrwych wrote:
Martin Wrote:

OzCableguy wrote:

Can anyone recommend a good electrolyte drink powder that I can
mix

up into

a biddon, is easy to get hold of, works, tastes ok and doesn't
cost

the

earth?

Almost all the studies and guidelines I have read on this topic
agree that the only mineral in sweat that might be important to
replace is sodium. Recent evidence, however, suggests that we don't
need to replace electrolytes during exercise. See

http://tinyurl.com/2gsvym

This paper suggests that we need only about 65 mmol of sodium (1.5
grams of sodium, equivalent to about 4 grams of salt) of sodium per
day.

See also www.saltmatters.org for very strong evidence supporting 50
mmol/day (about 1 gram of sodium or 3 grams of salt) as an upper
limit for sodium intake from all sources. Trevor Beard and others
suggest that most of us eat way too much salt, even if we don't
cook with salt or put salt on our food. We get much more salt than
we need from processed foods like bread. Too much salt causes
health problems, mainly high blood pressure, even in people who
exercise a lot. See also http://tinyurl.com/36cn5j.

www.saltmatters.org (see 'Safety issues') suggests that we loose a
lot less (about 70 - 85% less) sodium in sweat if we eat a low salt
diet.

My limited experience: Fow a few years I got headaches a few hours
after a moderate ride (30 - 60 km solo or in a group at about 27 -
30 km/hr ). Headache is one of the symptoms of hyponatraemia (low
blood sodium). I started putting salt in my water bottle and the
headaches seemed to stop. I have been on a low salt diet for about
6 weeks now - no additional salt in my water bottle and no
post-ride headaches (so far).

I am interested to hear other cyclists' experience with post-ride
headaches.

Martin

-- Removed z before replying by email.


you are saying that all electrolytes = sodium. The study you site
ONLY refers to sodium. it does not discuss calcium, potassium,
magnesium etc.

I'd like to see some of this research you allude to regarding "the
only mineral in sweat that might be important to replace is sodium."

The conversation was about cramping, and using electrolytes (in
general) to help with this issue.

I did not say that all electrolytes = sodium. Body stores of sodium are
relatively small and sodium is the electrolyte that is secreted at
highest concentration in sweat. The body stores of potassium are
relativley large and potassium is secreted at lowew concentration in
sweat. So, if you are going to take any electrolyte replacement, sodium
is probably more important than potassium. I don't know about readily
available body stores of magnesium and calcium, but they are also
secreted at low concentrations in sweat.

Some recent evidence:

'Compared with sodium and chloride, the concentration
of other electrolytes in sweat is low. For example, the
average concentrations a potassium, 5 mmol/L
(range 3-15 mmol/L); calcium, 1 mmol/L (range
0.3-2.0 mmol/L); and magnesium, 0.8 mmol/L
(range 0.2-1.5 mmol/L). Presently, there are no data
that make a compelling case for including these
electrolytes in fluids consumed during exercise
From the full text of:
Coyle (2004) Fluid and fuel intake during exercise
http://tinyurl.com/2utrln

'Sodium is the most important electrolyte in terms of
recovery after exercise. Without its replacement, water
retention is hampered. Potassium is also included in
sports drinks in concentrations similar to those in sweat.
Although there is strong evidence for the inclusion of
sodium, this is not the case with potassium. There is no
evidence for the inclusion of any other electrolytes.'
From the full text of:
SHIRREFFS et al 2004. Fluid and electrolyte needs for preparation and
recovery from training and competition
http://tinyurl.com/2msvhx

On cramp:

'exercise-associated muscle cramping in ironman triathletes is not
associated with a greater percent body mass loss or clinically
significant differences in serum electrolyte concentrations.'
From:
Sulzer et al 2005: Serum electrolytes in Ironman triathletes with
exercise- associated muscle cramping.
http://tinyurl.com/3643e6

There are many more studies of both electrolyte replacement and cramp,
although I don't think any have been done in people on low-salt diets. I
don't think the causes of cramp are properly understood. In any event,
Pubmed is a better source of reliable information than the advertising
of sports drink manufacturers. When you see an article that concludes
that sports drinks aid rehydration look to see if the authors were
funded by Gatorade etc. I suspect the sports drink manufacturers are
pulling the wool over our eyes and (very successfully) lightening our
wallets.

Martin

--
Removed z before replying by email.

Martin wrote:
warrwych wrote:
Martin Wrote:

I did not say that all electrolytes = sodium. Body stores of sodium are
relatively small and sodium is the electrolyte that is secreted at
highest concentration in sweat. The body stores of potassium are
relativley large and potassium is secreted at lowew concentration in
sweat.
[...]
'Compared with sodium and chloride, the concentration of other electrolytes
in sweat is low: [...] potassium, 5 mmol/L (range 3-15 mmol/L)

Another way to say it: most of your potassium sits in tissues, while the
amount in blood is tightly regulated to 3.5-5.0 mmol/L. Conversely,
most of sodium resides in the blood with a range 135-145 mmol/L (where
the normal level of Na+ & K+ in cells is close to the opposite of these
two figures).

So when you say that the normal range in sweat for potassium excretion
is 3-15mmol/L, with an average of 5mmol/L, then it made me wonder if
this was a case for replacement. But then I noticed that normal urine
levels of potassium tend to have wide variance, for most people based on
their intake.


In most likelihood you are right. I wonder if there are any direct
comparisons (sodium replacement vs full electrolyte replacements).


Russ.

Russ wrote:
Martin wrote:

warrwych wrote:

Martin Wrote:


I did not say that all electrolytes = sodium. Body stores of sodium
are relatively small and sodium is the electrolyte that is secreted at
highest concentration in sweat. The body stores of potassium are
relativley large and potassium is secreted at lowew concentration in
sweat. [...]
'Compared with sodium and chloride, the concentration of other
electrolytes
in sweat is low: [...] potassium, 5 mmol/L (range 3-15 mmol/L)


Another way to say it: most of your potassium sits in tissues, while the
amount in blood is tightly regulated to 3.5-5.0 mmol/L. Conversely,
most of sodium resides in the blood with a range 135-145 mmol/L (where
the normal level of Na+ & K+ in cells is close to the opposite of these
two figures).

So when you say that the normal range in sweat for potassium excretion
is 3-15mmol/L, with an average of 5mmol/L, then it made me wonder if
this was a case for replacement. But then I noticed that normal urine
levels of potassium tend to have wide variance, for most people based on
their intake.


In most likelihood you are right. I wonder if there are any direct
comparisons (sodium replacement vs full electrolyte replacements).


Russ.

A good way to start searching for this kind of information is to look
for papers by Tim Noakes (Noakes T or Noakes TD of the Sports Science
Institute of South Africa and author of "Lore of Running"). He is a
medical doctor and a runner and has been working in exercsie physiology
all his life. Energade is a listed 'commercial partner' of his
institute, but I have not seen any evidence that he is biased for or
against sports drinks. The 'related articles' link in Pubmed will help
to find other papers on electrolyte replacement.


--
Removed z before replying by email.

Martin Wrote:
warrwych wrote:
Martin Wrote:

OzCableguy wrote:

Can anyone recommend a good electrolyte drink powder that I can
mix

up into

a biddon, is easy to get hold of, works, tastes ok and doesn't
cost

the

earth?

Almost all the studies and guidelines I have read on this topic
agree that the only mineral in sweat that might be important to
replace is sodium. Recent evidence, however, suggests that we don't
need to replace electrolytes during exercise. See

http://tinyurl.com/2gsvym

This paper suggests that we need only about 65 mmol of sodium (1.5
grams of sodium, equivalent to about 4 grams of salt) of sodium per
day.

See also www.saltmatters.org for very strong evidence supporting 50
mmol/day (about 1 gram of sodium or 3 grams of salt) as an upper
limit for sodium intake from all sources. Trevor Beard and others
suggest that most of us eat way too much salt, even if we don't
cook with salt or put salt on our food. We get much more salt than
we need from processed foods like bread. Too much salt causes
health problems, mainly high blood pressure, even in people who
exercise a lot. See also http://tinyurl.com/36cn5j.

www.saltmatters.org (see 'Safety issues') suggests that we loose a
lot less (about 70 - 85% less) sodium in sweat if we eat a low salt
diet.

My limited experience: Fow a few years I got headaches a few hours
after a moderate ride (30 - 60 km solo or in a group at about 27 -
30 km/hr ). Headache is one of the symptoms of hyponatraemia (low
blood sodium). I started putting salt in my water bottle and the
headaches seemed to stop. I have been on a low salt diet for about
6 weeks now - no additional salt in my water bottle and no
post-ride headaches (so far).

I am interested to hear other cyclists' experience with post-ride
headaches.

Martin

-- Removed z before replying by email.


you are saying that all electrolytes = sodium. The study you site
ONLY refers to sodium. it does not discuss calcium, potassium,
magnesium etc.

I'd like to see some of this research you allude to regarding "the
only mineral in sweat that might be important to replace is sodium."

The conversation was about cramping, and using electrolytes (in
general) to help with this issue.

I did not say that all electrolytes = sodium. Body stores of sodium
are
relatively small and sodium is the electrolyte that is secreted at
highest concentration in sweat. The body stores of potassium are
relativley large and potassium is secreted at lowew concentration in
sweat. So, if you are going to take any electrolyte replacement,
sodium
is probably more important than potassium. I don't know about readily
available body stores of magnesium and calcium, but they are also
secreted at low concentrations in sweat.

Some recent evidence:

'Compared with sodium and chloride, the concentration
of other electrolytes in sweat is low. For example, the
average concentrations a potassium, 5 mmol/L
(range 3-15 mmol/L); calcium, 1 mmol/L (range
0.3-2.0 mmol/L); and magnesium, 0.8 mmol/L
(range 0.2-1.5 mmol/L). Presently, there are no data
that make a compelling case for including these
electrolytes in fluids consumed during exercise
From the full text of:
Coyle (2004) Fluid and fuel intake during exercise
http://tinyurl.com/2utrln

'Sodium is the most important electrolyte in terms of
recovery after exercise. Without its replacement, water
retention is hampered. Potassium is also included in
sports drinks in concentrations similar to those in sweat.
Although there is strong evidence for the inclusion of
sodium, this is not the case with potassium. There is no
evidence for the inclusion of any other electrolytes.'
From the full text of:
SHIRREFFS et al 2004. Fluid and electrolyte needs for preparation and
recovery from training and competition
http://tinyurl.com/2msvhx

On cramp:

'exercise-associated muscle cramping in ironman triathletes is not
associated with a greater percent body mass loss or clinically
significant differences in serum electrolyte concentrations.'
From:
Sulzer et al 2005: Serum electrolytes in Ironman triathletes with
exercise- associated muscle cramping.
http://tinyurl.com/3643e6

There are many more studies of both electrolyte replacement and cramp,
although I don't think any have been done in people on low-salt diets.
I
don't think the causes of cramp are properly understood. In any event,
Pubmed is a better source of reliable information than the advertising
of sports drink manufacturers. When you see an article that concludes
that sports drinks aid rehydration look to see if the authors were
funded by Gatorade etc. I suspect the sports drink manufacturers are
pulling the wool over our eyes and (very successfully) lightening our
wallets.

Martin

--
Removed z before replying by email.

When you say "Recent evidence, however, suggests that we don't
need to replace electrolytes during exercise." then immediately refer
to a research paper investigating sodium requirements in ironman
events, then it reads as though you are saying all electrolytes =
sodium, and are making sweeping statements, that are not directly
supported by the evidence you provide, which are kinda related but not
quite.

I don't disagree with your qualifying post. However, sports drinks (not
just talking gatorade, powerade, staminade here) are not just for
"sweat" recovery, and it's important to note that for proper muscle
functioning under load, various minerals are required for muscles to
fire properly, including calcium, potassium etc. If you lose some of
minerals via sweat, as well as normal physiological processes during
exercise, they need to be replaced. Usually cramping is not "caused" by
sweating, which is a byproduct of exercise. Cramping may be caused (and
yes, it's not fully known what causes cramping, why it happens, what
remedies it for everyone) by mineral imbalances, amongst others things.


--
warrwych