Sweat Test (Salt Loss) anyone

Aug 6, 18 8:13

Post #1 of 28 (4651 views)

Anyone had a formal sweat test done to evaluate their salt (and other electrolyte) loss? On one podcast (can't recall which one) a person from Australia was talking about his doing a patch test -- put a small patch on in a spot or two, weigh yourself and drinks before and after. He then determines amount of electrolyte in the patch -- and your real electrolyte loss.

I continue to have trouble keeping enough salt, etc in the system. Pre-loading with the Skratch Hyper hydration mix has helped. Last weekend I got my dreaded headache from too few electrolytes, despite trying to hydrate during the race. Yes, I was somewhat dehydrated. But years have taught me this specific headache requires salt to get rid of it.

Have not found much in the US. I have only seen Levelen offering a test.

What experiences do you have with testing?

Thanks

Re: Sweat Test (Salt Loss) anyone [prefersdirt] [ In reply to ]

Aug 6, 18 8:38

Post #2 of 28 (4622 views)

No affiliation with these folks, though i have talked with them a while back...

https://www.precisionhydration.com/pages/sweat-testing

Brandon Marsh - Website | @BrandonMarshTX | RokaSports | 1stEndurance | ATC Bikeshop |

Re: Sweat Test (Salt Loss) anyone [prefersdirt] [ In reply to ]

Aug 6, 18 10:15

Post #3 of 28 (4535 views)

I did the Precison Hydration test. Probably the single best $150 I have spent in triathlon. Based on the results I approximately doubled my fluid and sodium intake (it takes some practice to understand how much your body can consume).

Re: Sweat Test (Salt Loss) anyone [sch340] [ In reply to ]

Aug 6, 18 10:59

Post #4 of 28 (4485 views)

So you did the actual sweat test at once of their centers or they were in your area?

Did you compare it to their online calculator?

Brandon Marsh - Website | @BrandonMarshTX | RokaSports | 1stEndurance | ATC Bikeshop |

Re: Sweat Test (Salt Loss) anyone [-JBMarshTX] [ In reply to ]

Aug 6, 18 11:35

Post #5 of 28 (4444 views)

There is a lady here in NYC where I live that contracts with Precision and works out of a PT studio. Her equipment was all there, the test was performed using the disc, and at the end of the test you get a number in mg / L (mine was 1,100 something). She used the online calculator as a supplement to the test results but it was more of a confirmation than a standalone result, I believe.

She provided me with a spreadsheet as part of the $150 fee where I logged my weight pre and post workouts to get an indication of fluid loss (and using, the test number, corresponding sodium loss) which then enables you to understand an appropriate fluid and sodium replacement strategy.

For example if you sweat 1 L / hr and your sodium concentration is 1,000 mg/L you will want to replace between 700-900mg per hour (they recommend a 70-90% replacement rate that you can experiment with).

She told me the concentration (mg/L) doesn't vary - just your sweat rate.

They try to promote their products as part of the test but you can take the numbers and buy whatever product(s) fit your needs the best.

Re: Sweat Test (Salt Loss) anyone [sch340] [ In reply to ]

Aug 6, 18 11:37

Post #6 of 28 (4431 views)

Just wondering. I've got a detailed spreadsheet that I use for my athletes so they can calculate what they're taking in, but the loss is kind of based on trial and error.

1,000 mg/hr seems like a good starting point.

Thanks for the reply.

Brandon Marsh - Website | @BrandonMarshTX | RokaSports | 1stEndurance | ATC Bikeshop |

Re: Sweat Test (Salt Loss) anyone [-JBMarshTX] [ In reply to ]

Aug 6, 18 11:42

Post #7 of 28 (4418 views)

I think 1,000 would be a good starting point. She said I was a little bit on the salty side but nothing too outside of the norm. If your athletes see significant salt staining on their kits post-race it may be an indication of a higher salt concentration.

Re: Sweat Test (Salt Loss) anyone [sch340] [ In reply to ]

Aug 6, 18 12:08

Post #8 of 28 (4385 views)

sch340 wrote:

I did the Precison Hydration test. Probably the single best $150 I have spent in triathlon. Based on the results I approximately doubled my fluid and sodium intake (it takes some practice to understand how much your body can consume).

What were you using for fluids before you did the test?
One 12oz serving of EFS has about 1000mg of electrolytes I think, nice and simple. Were you using something more diluted?

Re: Sweat Test (Salt Loss) anyone [-JBMarshTX] [ In reply to ]

Aug 6, 18 13:45

Post #9 of 28 (4316 views)

Only problem with Precision Hydration's setup is a lack of a place near me. I live in Indianapolis. Hard to travel far for just a test.

Re: Sweat Test (Salt Loss) anyone [SBRcanuck] [ In reply to ]

Aug 6, 18 14:09

Post #10 of 28 (4299 views)

SBRcanuck wrote:

sch340 wrote:

I did the Precison Hydration test. Probably the single best $150 I have spent in triathlon. Based on the results I approximately doubled my fluid and sodium intake (it takes some practice to understand how much your body can consume).

What were you using for fluids before you did the test?
One 12oz serving of EFS has about 1000mg of electrolytes I think, nice and simple. Were you using something more diluted?

Beforehand I was just using Powerade Endurance and just winging it on the course... took a few bonks in hot weather to finally get me to get tested.

I just looked up EFS - it has 400 cal and 400mg of sodium. For me that's too high of a cal/sodium ratio. But you could use it in conjunction with some salt pills to get you up to 1000mg sodium.

I currently use a mix of custom blend infinit, gels and salt pills. It's tough to find one product that gets you to exactly where you need to be for both sodium and calories.

Re: Sweat Test (Salt Loss) anyone [sch340] [ In reply to ]

Aug 6, 18 14:24

Post #11 of 28 (4276 views)

Pouring enough fluid in during a race is also tough. Constantly working on that.

Discovered the hard way what happens w too much sodium. At least I THINK that was the cause.

Re: Sweat Test (Salt Loss) anyone [prefersdirt] [ In reply to ]

Aug 6, 18 14:29

Post #12 of 28 (4270 views)

I did the levelen sweat testing for both the bike and run portions. I knew already I was a heavy salter(from the salty skin and salt covered clothes post workouts), but the results shocked me. I was WAYY off on how much sodium I should be taking in. Have since adjusted to using the EFS-Pro mix and haven't seen the same issues as before since. I still think its a bit of trial and error, but they can at least get you in the ballpark.

Re: Sweat Test (Salt Loss) anyone [sch340] [ In reply to ]

Aug 6, 18 14:34

Post #13 of 28 (4262 views)

sch340 wrote:

There is a lady here in NYC where I live that contracts with Precision and works out of a PT studio. Her equipment was all there, the test was performed using the disc, and at the end of the test you get a number in mg / L (mine was 1,100 something). She used the online calculator as a supplement to the test results but it was more of a confirmation than a standalone result, I believe.

She provided me with a spreadsheet as part of the $150 fee where I logged my weight pre and post workouts to get an indication of fluid loss (and using, the test number, corresponding sodium loss) which then enables you to understand an appropriate fluid and sodium replacement strategy.

For example if you sweat 1 L / hr and your sodium concentration is 1,000 mg/L you will want to replace between 700-900mg per hour (they recommend a 70-90% replacement rate that you can experiment with).

She told me the concentration (mg/L) doesn't vary - just your sweat rate.

They try to promote their products as part of the test but you can take the numbers and buy whatever product(s) fit your needs the best.

Doesn't the sodium concentration of sweat depend directly on the amount of sodium in the blood? That is, if you loaded up on sodium before the test, your body will respond by dumping sodium in sweat to maintain the correct level in the blood. If you were "low" on sodium to begin with, your body will dump less sodium; again, to maintain equilibrium.

Isn't sweating used by the body primarily for cooling?

More information than you want: https://www.ncbi.nlm.nih.gov/...articles/PMC5371639/ There is a large variation in Na+ concentration within a given individual.

----------------------------------
"Go yell at an M&M"

Re: Sweat Test (Salt Loss) anyone [prefersdirt] [ In reply to ]

Aug 6, 18 14:41

Post #14 of 28 (4253 views)

My issue with these tests is not the test itself, it's the knowledge of what to do with it after.

You do not and should not replace at 1:1.
The art is calculating osmolarity changes over the course of an event to keep everything in a good range.
As far as I know, most do not take this into consideration.

I talk a lot - Give it a listen: http://www.fasttalklabs.com/category/fast-talk
I also give Training Advice via http://www.ForeverEndurance.com

The above poster has eschewed traditional employment and is currently undertaking the ill-conceived task of launching his own hardgoods company. Statements are not made on behalf of nor reflective of anything in any manner... unless they're good, then they count.
http://www.AGNCYINNOVATION.com

Re: Sweat Test (Salt Loss) anyone [sch340] [ In reply to ]

Aug 6, 18 14:57

Post #15 of 28 (4234 views)

When talking about sweating, is sodium the only concern? What about the other electrolytes (cal, mag, potas. etc)?
EFS may only have 400 sodium, but also has the others.

Re: Sweat Test (Salt Loss) anyone [SBRcanuck] [ In reply to ]

Aug 6, 18 15:46

Post #16 of 28 (4206 views)

The others matter, but sodium is the main one. Race nutrition comes down to water, salt, and sugar. Essentially.

Too much Mg and you'll get the runs. First Endurance re-formulated some of the original EFS based on a lot of feedback, research, etc. for magnesium specifically. They reduced the concentration greatly.

Not sure what with too much potassium. Most of the main electrolyte formulations have more than just sodium. I think that Salt Stick used an average ratio of electrolytes in human sweat to come up with their ratios. Succeed S!Caps does something similar. Those + EFS were my go-to for long races.

Brandon Marsh - Website | @BrandonMarshTX | RokaSports | 1stEndurance | ATC Bikeshop |

Re: Sweat Test (Salt Loss) anyone [prefersdirt] [ In reply to ]

Aug 6, 18 15:48

Post #17 of 28 (4205 views)

There is a company called Levelen. They will send you a sweat test kit and instructions. It is super simple. They gave pretty good info overall with your results. I think it was $80 or $85. I don't have any other experience with home sweat tests. Often times universities will offer it in the Kinesiology or Exercise Science department. https://www.levelen.com

Re: Sweat Test (Salt Loss) anyone [klehner] [ In reply to ]

Aug 7, 18 6:46

Post #18 of 28 (4048 views)

klehner wrote:

Doesn't the sodium concentration of sweat depend directly on the amount of sodium in the blood? That is, if you loaded up on sodium before the test, your body will respond by dumping sodium in sweat to maintain the correct level in the blood. If you were "low" on sodium to begin with, your body will dump less sodium; again, to maintain equilibrium.

Isn't sweating used by the body primarily for cooling?

More information than you want: https://www.ncbi.nlm.nih.gov/...articles/PMC5371639/ There is a large variation in Na+ concentration within a given individual.

Here is a good article that they pointed me to with respect to pre-loading:

https://www.precisionhydration.com/blogs/hydration_advice/how-to-start-hydrated-and-why-that-is-important-sodium-preloading-what-to-do-before-a-race-hydration

If you're "low" on sodium, i.e. diluted, your body will respond by peeing more.

Re: Sweat Test (Salt Loss) anyone [xtrpickels] [ In reply to ]

Aug 7, 18 6:50

Post #19 of 28 (4039 views)

xtrpickels wrote:

My issue with these tests is not the test itself, it's the knowledge of what to do with it after.

You do not and should not replace at 1:1.
The art is calculating osmolarity changes over the course of an event to keep everything in a good range.
As far as I know, most do not take this into consideration.

The nutritionist I worked with recommended a 70-90% replacement ratio, with the exact number being determined by experimentation in training. As part of the testing fee she worked with me to develop a training and racing nutrition strategy which took into account my sweat rate (in L/hr) and sodium concentration in my sweat (in mg/L) after logging sweat rates for about a dozen or so workouts in different scenarios.

Re: Sweat Test (Salt Loss) anyone [xtrpickels] [ In reply to ]

Aug 7, 18 9:19

Post #20 of 28 (3960 views)

A good rule of thumb is 100 calories per 12 ounces of fluid. The calorie/fluid ratio I think is more important than adding in the electrolytes to really calculate an overall osmolarity. I try to keep it really simple and basic in that.

200 calories per hour = minimum of 24 ounces of fluid
300 cal = 36 ounces
400 cal = 48 ounces

This keeps it simple to sort out. Add in the sodium as needed based on the total sum of sports drink, salt tabs, and/or gels.

Whether it's 70-90% replacement as another poster said or closer to 1:1, it should be duplicated in training. This leaves fewer variables to chance on race day.

Brandon Marsh - Website | @BrandonMarshTX | RokaSports | 1stEndurance | ATC Bikeshop |

Re: Sweat Test (Salt Loss) anyone [-JBMarshTX] [ In reply to ]

Aug 7, 18 10:27

Post #21 of 28 (3902 views)

-JBMarshTX wrote:

A good rule of thumb is 100 calories per 12 ounces of fluid. The calorie/fluid ratio I think is more important than adding in the electrolytes to really calculate an overall osmolarity. I try to keep it really simple and basic in that.

200 calories per hour = minimum of 24 ounces of fluid
300 cal = 36 ounces
400 cal = 48 ounces

This keeps it simple to sort out. Add in the sodium as needed based on the total sum of sports drink, salt tabs, and/or gels.

Whether it's 70-90% replacement as another poster said or closer to 1:1, it should be duplicated in training. This leaves fewer variables to chance on race day.

Infinit calculates the osmolality of its custom mixes which has helped me in addition to rules of thumb such as this.

Your last point can't be stressed enough, not just because you want to make sure your body doesn't react poorly on race day, but also because you can test your limits under certain conditions. I can inhale a disgusting amount of liquid both biking and running and I still am only replacing about half of what I lose (about 5 pounds per hour running, in hot temps).

Re: Sweat Test (Salt Loss) anyone [sch340] [ In reply to ]

Aug 7, 18 12:55

Post #22 of 28 (3830 views)

That is not necessarily true. If you train in a humid environment like Florida, you're always wet (from sweat), so you won see any salt stains.

I believe weighing yourself before and after exercise to be the best way to calculate electrolyte depletion the way it is explained in this discussion a few posts earlier

http://www.verynooty.com

Last edited by: BigH: Aug 7, 18 12:58

Re: Sweat Test (Salt Loss) anyone [klehner] [ In reply to ]

Aug 7, 18 13:06

Post #23 of 28 (3821 views)

klehner wrote:

sch340 wrote:

There is a lady here in NYC where I live that contracts with Precision and works out of a PT studio. Her equipment was all there, the test was performed using the disc, and at the end of the test you get a number in mg / L (mine was 1,100 something). She used the online calculator as a supplement to the test results but it was more of a confirmation than a standalone result, I believe.

She provided me with a spreadsheet as part of the $150 fee where I logged my weight pre and post workouts to get an indication of fluid loss (and using, the test number, corresponding sodium loss) which then enables you to understand an appropriate fluid and sodium replacement strategy.

For example if you sweat 1 L / hr and your sodium concentration is 1,000 mg/L you will want to replace between 700-900mg per hour (they recommend a 70-90% replacement rate that you can experiment with).

She told me the concentration (mg/L) doesn't vary - just your sweat rate.

They try to promote their products as part of the test but you can take the numbers and buy whatever product(s) fit your needs the best.

Doesn't the sodium concentration of sweat depend directly on the amount of sodium in the blood? That is, if you loaded up on sodium before the test, your body will respond by dumping sodium in sweat to maintain the correct level in the blood. If you were "low" on sodium to begin with, your body will dump less sodium; again, to maintain equilibrium.

Isn't sweating used by the body primarily for cooling?

More information than you want: https://www.ncbi.nlm.nih.gov/...articles/PMC5371639/ There is a large variation in Na+ concentration within a given individual.

Sweat at the secretory coil is isotonic with plasma regarding Na, but becomes hypotonic with plasma in Na as it flows up the duct and Na is reabsorbed. Folks who are well heat acclimated reabsorb more Na than folks who are not well acclimated. Also, at some point your sweat rate can overcome your body's ability to reabsorb Na in the duct and the amount of Na in your sweat increases.

___________________________________________________
Taco cat spelled backwards is....taco cat.

Re: Sweat Test (Salt Loss) anyone [prefersdirt] [ In reply to ]

Aug 8, 18 2:03

Post #24 of 28 (3732 views)

A lot of these references are US based. Anyone reading this know of a Germany based sweat test provider?
Or, even better, is there a way to accurately do a sweat test at home?

Paulo Matos

Re: Sweat Test (Salt Loss) anyone [prefersdirt] [ In reply to ]

Aug 8, 18 14:40

Post #25 of 28 (3596 views)

prefersdirt wrote:

Anyone had a formal sweat test done to evaluate their salt (and other electrolyte) loss? On one podcast (can't recall which one) a person from Australia was talking about his doing a patch test -- put a small patch on in a spot or two, weigh yourself and drinks before and after. He then determines amount of electrolyte in the patch -- and your real electrolyte loss.

I continue to have trouble keeping enough salt, etc in the system. Pre-loading with the Skratch Hyper hydration mix has helped. Last weekend I got my dreaded headache from too few electrolytes, despite trying to hydrate during the race. Yes, I was somewhat dehydrated. But years have taught me this specific headache requires salt to get rid of it.

Have not found much in the US. I have only seen Levelen offering a test.

What experiences do you have with testing?

Thanks

I had 2 back to back horrible marathons due to dehydration/cramping. I used Levelen several weeks ago. They use the same patch test you describe. I found out I lose 6.5 grams of salt per hour of training on a 60 degree day. I know there is no way to to replace that much alt lost. I used that info to figure out a race plan for marathon #3. I took a salt tab every 20 minutes and drank 30-35 ounces of fluid per hour. I was taking 1.5 grams of salt per hour.

Bruce

Last edited by: bantjh2o: Aug 8, 18 14:40

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