Comments on Joe Friel's Blog: Hydration and Exercise, Part 2

Hi Joe, Thanks for your reply. I haven't gone thro...

2008-10-31T13:56:00.000-08:00

Hi Joe, Thanks for your reply.

I haven't gone through it but will now. It is a surprising result, something that, as you say, is counter-intuitive.

Simon

Hi Simon--I understand your point. Notice that if ...

2008-10-26T12:20:00.000-08:00

Hi Simon--I understand your point. Notice that if you even double the amount of sodium lost in sweat the concentration of sodium in body fluids still rises from the starting point of 140. The figure would then go from 142.5 to 140.5. And I used the high end of the sodium lost per liter of sweat in the initial example - 60mm.

Hi Joe, is this actually the full story? Your exam...

2008-10-26T11:26:00.000-08:00

Hi Joe,

is this actually the full story? Your example only deals with a nett loss of water from the body. ie it compares body mass/water content before and after the event then assumes the amount of salt loss or salt concentration change is dependant on this nett mass change. It doesn't mention that throughout the duration of the exercise water and salt would be lost but some of the water would be replaced by drinking. so this needs to be taken into account as more salt would be lost than that due simply to a before and after weight comparison.

Hi Coach Troy--Haven't seen you in a while. Thanks...

2008-09-22T09:05:00.000-07:00

Hi Coach Troy--Haven't seen you in a while. Thanks for your concern. Things are slowly getting back to normal around here.

Hi Willy--I'll take a stab at these...I never hear...

2008-09-22T09:03:00.000-07:00

Hi Willy--I'll take a stab at these...
I never heard of salt bonking. Bonking refers to running out of energy, typically carbohydrate.

When salt stores are depleted (meaning here are no more) you die.

Just to correct a small error (may have been a typo)...sodium concentration INCREASING triggers thirst.

Interesting - yet once you think about it it's har...

2008-09-22T07:35:00.000-07:00

Interesting - yet once you think about it it's hardly surprising that Nature's mechanism for hydration works correctly - rarely do we find a better way than evolution has for anything...

What happens when you're "salt bonking" ?The studi...

2008-09-22T01:13:00.000-07:00

What happens when you're "salt bonking" ?
The studies you've quoted are limited to 4 to 6h efforts.

What happens when your "salt stocks" are depleted ?

I can run 3h without consuming any sugars, this won't get me to say : "consuming sugar during an endurance event is pointless" Cause I'm likely to bonk soon after those first three hours...

From my own experience, I don't need to supplement with sodium for events shorter than HIM. Regarding IMs, supplementing with sodium helps me a lot when it's really hot, I cramp a lot less and assimilate water better (i.e. I feel less bloated).

Furthermore, as you said, sodium concentration decrease is what activates the thirst mechanism. What happens when you're totally sodium depleted or at least don't have anymore enough sodium in your blood to compensate the lower concentration induced by water intake? It seems like you're going to go right into dehydratation, isn't it ? Because the thirst mechanisme won't kick in (if one sticks to your reasoning).

Thanks for sharing your thoughts in this blog which is always interesting and relevant.

Sorry to hear about your house. Hope things have ...

2008-09-21T18:37:00.000-07:00

Sorry to hear about your house. Hope things have settled down for you and your family.

This is a fascinating report, I look forward to part 3.