Rob,

Bear in mind that I'm regurgitating what I know from chemistry classes, so don't
put any real stock in it at all, I am not an expert or even amateur in this
area.

But I do remember that an over abundance of certain cations (positively charged
ions such as sodium K+) will force other cations into or out of (out of I think
in the case of an abundance) solution.

What this discussion made me think about a possibility, was that if you are
taking in a lot of potassium and sodium through electrolytes, and you aren't
replacing calcium, you can have a situation where you have a lot more potassium
(K+) and sodium (Na+) ions than calcium (Ca2+). This could cause calcium that
is not into solution (in bones or tissue perhaps) to come into solution. The
opposite may be true also - lack of electrolytes may cause calcium that is not
into solution to be drawn from bones into solution balance the solution. What
really happens in the body as opposed to a test tube I don't know enough to say.

And when I looked at my endurox pills they didn't have a calcium level listed
(looking again they had calcium phosphate as an ingredient, so perhaps there is
a small amount). However, my Gu packets have 2% of DV for calcium, which is
about 20 milligrams.

Here' s a quick comparison:

Gu (1 packet, 1 serving)
50mg Na+ (sodium)
35mg K+ (potassium)
20mg (calculated from 2% DV) Ca2+ (calcium)

Endurox (1 capsule, 1/2 serving)

15mg Mg2+ (magnesium)
7.5mg Zn2+ (zinc)
75mg Na+ (sodium)
10mg K+ (potassium)
?mg Ca2+ (calcium, some provided in the form of dicalcium phosphate)

Tums Regular Strength (1 serving, http://www.tums.com/faq_calcium.aspx)
200mg Ca2+ (calcium)

Draw from these numbers what you will. I had never used an Endorox pill until a
month ago, been using Gu for 10 years. Never tried Tums but my Aunt who
completed dozens of brevets recommended it. I also relied on fruit and gatorade
for electrolytes on long rides so I don't know that much in this area than what
I've done.



----- Original Message ----
From: Rob Hawks <rob.hawks@...>
To: Fred Moyer <phredwolf@...>
Cc: Massimiliano Poletto <sfrandon@...>; Bruce Berg
<bberg@...>; sfrandon@yahoogroups.com
Sent: Wednesday, July 1, 2009 5:26:21 PM
Subject: Re: [sfrandon] FW: [GPC] Is cycling bad for your health?

Fred,

Apologies. I am not sure I understand this:

"Another thing to consider is that if you are taking electrolytes (my
endurox bottle does not list calcium), it is theoretically possible
that you can displace the levels of available calcium in your system
because of the replacement of potassium and other cations, and lack of
calcium replacement."

Can you elaborate (and perhaps simplify this for a dolt? (me))

rob

On Wed, Jul 1, 2009 at 4:41 PM, Fred Moyer<phredwolf@...> wrote:
>
>
>
> Looking at the amount of elemental calcium in Tums, it is about 200 mg for
> standard strength, so you would need about one tablet per hour according to
> the article.
>
> Another thing to consider is that if you are taking electrolytes (my endurox
> bottle does not list calcium), it is theoretically possible that you can
> displace the levels of available calcium in your system because of the
> replacement of potassium and other cations, and lack of calcium replacement.
> I'm not a biochemist though, so my statement is unfounded except for what I
> remember from chemistry classes.
>
> ----- Original Message ----
> From: Massimiliano Poletto <sfrandon@...>
> To: Bruce Berg <bberg@...>
> Cc: sfrandon@yahoogroups.com
> Sent: Wednesday, July 1, 2009 3:34:25 PM
> Subject: Re: [sfrandon] FW: [GPC] Is cycling bad for your health?
>
> I have found that eating calcium carbonate tablets (Tums, etc.)
> occasionally on long rides, especially when it's hot, makes me feel
> better. It both settles the stomach and prevents cramps. I did not
> know, however, that the rate of calcium loss due to perspiration could
> be as high as claimed by the article (hundreds mg/hour).
>
> max
>
> On Wed, Jul 1, 2009 at 1:57 PM, Bruce Berg<bberg@...> wrote:
>>
>>
>>
>>
>> An interesting New York Times article on bone density, or the loss of it,
>> in
>> competitive cyclists. But it isn’t clear how much it applies to us long
>> distance recreational riders. It probably does say that drinking milk or
>> other calcium rich beverages while on our brevets is probably a very good
>> idea and suggests that we might be better off if we get some other form of
>> exercise on a regular basis, be it weight lifting, running, hiking, etc,
>> but
>> probably not swimming.
>>
>> Bruce
>>
>>
>>
>>
>> http://well.blogs.nytimes.com/2009/07/01/is-bicycling-bad-for-your-bones/?hp
>>
>>
>>
>>
>>
>>
>>
>>
>
> ------------------------------------
>
> sfrandon :: San Francisco Randonneurs
> http://sfrandonneurs.org
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>
>