Acute sodium loading

a la Greenleaf and/or Sims.

Anybody tried it? Do share…

Well I tried it…in a sort of ‘Phase I’ way. It’s not toxic, at least. :smiley:

Trailblaze and let us know how it goes. I generally draw the line at CoQ10 and Collagen but this in in the same category and all eyes/ears on what you find.

FWIW I’m having some weird stuff happening with Precision Hydration 1500 in the 90-100F heat.

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What qualifies as weird stuff? I’m genuinely curious.

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Stacy used a concoction that is a little more than 2x as salty as precision hydration. About 4000 mg/l. :flushed: But the object isn’t hydration…it’s acute plasma volume (~4hrs or so).

the Stacy paper is interesting, and might explain the unusually low HR on a few recent hard efforts.

Cliffs for those of us too lazy to find and read the study or whatever it is this is about?

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The Stacy study set out to determine benefits of sodium preloading (pre-exercise hyperhydration) in trained males (average vo2max 57.5, average age 36 yrs old) that ran in hot conditions (32C / 90F).

Sodium has molar mass of 22.99g/mmol, therefore the high sodium beverage had 3770mg sodium per liter. The runners in that study ingested ~750ml starting 105 minutes before exercise.

That is about 2828mg of sodium, almost 4 packets of Precision Hydration 1500. Start drinking an hour and 45 minutes before exercise, and drink it evenly in 7 portions over an hour. Then run in 32C / 90F temperature controlled chamber.

Benefits:

  • increased time to exercise termination
  • lower core temperature
  • lower perceived exertion
  • tendency for a lower heart rate
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Oh nice, thanks! Makes me not so worried about upping my sodium intake for a race this weekend!

I have been wanting to try pre loading sodium, even brought a bottle of water with some sodium citrate in it to work this morning to test out.

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From several different studies…

Because I’m on my phone and don’t want to try and read the study on that…any effect on weight? Did the added sodium lead to higher water retention?

Some interesting commentary in this article:

in the “What About Hyper-Hydration or Pre-Load Hydration Products?” section.

GUF was quite the responder to HyperAde!

Yes. If I read the paper(s) correctly about 150g to 200g difference…mostly due to lower urine production in the sodium loaded group.

But it’s worth it to ask about bodyweight in the days after sodium loading. I don’t find the answer in these papers (could be I’m just missing it) but would guess +couple lbs for sure. But the scales don’t lie and right now the ‘n of 1’ answer is ‘too small to measure’. Surprise, surprise.

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But responded negatively to gatorade. Go figger.

always entertaining to look at individual HR responses, and FWIW while GUF’s performance didn’t increase with Gatorade we do see a lower terminal HR vs no sodium preloading.

Yes. I tried 9g per liter… ie drinking saline. Effect: diarrhea. I only used NaCl for that.

I have been legitimately too scared to do anything more than 2000mg per liter since. And I always use sodium citrate for a large majority of it.

I’ll try higher concentrations and report back.

The literature is pretty convincing that there is a benefit to performance, even if not hot, but especially if hot, and even if there is substantial weight gain. I suspect that any weight gain would be outweighed by performance in any scenario (even hill TT’s) but don’t have the data to back that suspicion up.

I routinely have my athletes use 1500-1800mg/L in the hours leading up to competition.

Key: don’t sodium-load too early, and definitely don’t start chugging plain water after increasing sodium consumption before an event. Drink more sodium-containing beverages or you may just end up with a washout effect, leaving you hyponatremic.

Also don’t do this if you’re on diuretics for BP or have untreated high BP.

Glycerol + Sodium is also interesting, but I have not yet dabbled. Looks like I’ve got some reading and experimentation to do.

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Quick update to my reading, which should have been obvious to me, but wasn’t until I saw this chart:

I’ve always told folks not to hyperhydrate with glycerol because of increased risk of hyponatremia if it goes poorly, and just thought that it might result in increased water retention to the point of hyponatremia. What should have been obvious to me was that sodium excretion increases with glycerol loading because of the fluid retention. Kidneys excrete the sodium to try to bring blood sodium levels back to normal.

Implication:
Don’t glycerol load without sodium.

Scratch that… don’t use glycerol at all. It’s banned by WADA for being a masking agent, even though it has no such effect, even in concert with sodium loading. Glycerol is a less potent blood volume enhancer than sodium.

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Okay back to sodium loading… my goodness some of the literature uses high concentrations of NaCl. 7.5g per liter!
GOULET 2017, Salt + Glycerol-Induced Hyperhydration Enhances Fluid Retention More than Salt- or Glycerol-Induced Hyperhydration.pdf (906.9 KB)

That’s what I was expecting, too. Dr Alex doesn’t need my advice for this…but for the average forum member reading this thread: don’t just slam it! Ha! Follow the protocol.

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I don’t get this part of it. Is drinking 1 liter with 2 grams of sodium in it followed by 1 liter of plain water significantly different that drinking 2 liters with 1 gram each over the same time period?
Also, how do sodium loading and ‘pre-hydration’ interplay? The summary of the study has people drinking 750ml of fluid before exercise - that doesn’t sound like much pre-hydration in terms of volume.

I had previously thought that increased salt before workout leads to increased water retention which then allows you to start exercise with ‘extra’ water on board, and that it was the extra water that was the primary goal. It sounds like having extra sodium is also beneficial even if not also accompanied with ‘lots’ of water.
Should the main focus be on salt content or water volume? (obviously there is a max concentration that is tolerable.)

I am perplexed that it only took one 8oz bolus of 9g/L to cause such a pronounced effect on me. The folks in the Goulet studies are consuming 7.5g/L for a total of close to 2L (64oz, with each bolus being close to 16oz) of fluid over 60-80minutes of consumption.

Makes me think I mis-measured and not by a small margin, or I’ve got a glass gut with regard to sodium.

Here’s more fodder for the discussion:

See table 6 here:

The Goulet group loves the 7.5g/L sodium concentration. I just have the hardest time believing that none of their subjects had an osmotic laxative effect given how rapid and pronounced mine was, when using 9g/L. Within 3 minutes I noted something was “off” in my gut. Within 30 minutes I was in and out of the bathroom for the next couple hours.
https://cdnsciencepub.com/doi/abs/10.1139/apnm-2014-0243