Can you help me understand what is happening within us when salt residue begins to show? I understand our sweat includes sodium, and this is residue from that sodium. However, there “seems” to be a connection between performance and the existence of this residue. Is the residue a symptom of something physiological? Perhaps this is a sign the body is no longer processing electrolytes properly?
My wife noticed a number of athletes at IMC with reside and commented that “none looked good”. On the other hand, all those who looked strong were residue free.
I think it means you are sweating a lot and the sweat is mostly evaporating off of your skin, hat, shirt, etc. before it drips to the ground. As the drop evaporates the concentration of salt in the remaining water becomes high enough that it forms the white crystals on your skin. A high salt diet and lack of training will result in more salt being lost through sweat. As you become better conditioned, the sweat glands become more effective at resorbing salt but it is a concentration-based process so if you had a boat load of soy sauce last night you are still going to lose a bunch of salt.
I’m curious too…as I was one of the fellows you’re wife might have noticed. The photos came back and sure enough, the front of my kit was covered in salt residue.
Race: weather nice at sunny 75 and warmer during the day…never felt baking hot on the bike… Run ideal temp
swim: started cramping 1/2 way during swim. first left leg, then right. had to slow, relax…this can’t be happening - already?
Bike: used a cluster dextrin (carb) that had electrolyte in it but did not use any extra salt…didn’t take simple sugars or gatorade until around mile 75. Started cramping real bad after mile 75. figured out how to change my pedal stroke and work through cramp.
Run: disaster hit about mile 9. couldn’t run, rather jog, any more. when I pulled over trying to balance and bend over, a fellow handed me some salt pills and I took them. Amazingly, after several more miles of walking, I was able to start running again. I continued with salt pills remainder of race and was simply amazed how my legs could take weight again. you mean this wasn’t a fatigue/glucose/fuel issue but a salt issue? oh man, I screwed this up
… which leads me to believe the entire day, I got behind on my salt and paid the price in severe cramping and leg lock. Naturally, disappointed…you mean all I had to do was stay ahead of my salt loss and I actually could have stayed on task?
finished over 12:40 with a 5 hour marathon…what a knucklehead
Pretty sure it is genetic or hereditary whatever you want to call it.
I sweat like a damn pig, always have, doesn’t change at all no matter what my fitness level. And I make enough salt to fill a shaker after a good long ride. My hair gets big clumps of salt in it, you can brush it off my face, kit is covered, etc. Have a few riding buddies who are the same, others of same or lesser fitness don’t salt at all, really don’t think it is a fitness issue. My Grandfather sweat like a pig as well.
I had an interesting chance to see this phenomenon while working the Bike Corral at IM Boulder in 2014. I was working the shift from 2 to 6pm, which means I was seeing people on an 11-12 hour pace at the start of my shift, all the way to the midnight shift of people that would be trying to beat the course cut-off. There was a clear trend towards greater salt-streaks as the day went on.
Part of that is a simple explanation: these racers had been out for several more hours, and in higher heat. That may account for all of the difference, but I could believe there are more factors. Certainly the BMI crept up as the time went by - although there were plenty of specimens still coming in towards the cutoff.
Compare a 5 hour biker to a 7 hour ride.
The fast biker is probably on his/her bike between 8-8:30AM and riding in cooler morning temps for ~ 2 hours. They will have ~ 3 hours where temps will be rising, but likely the roads are still cool, more shade due to lower sun angles and more chances to cool off, finishing between 12- and 1.
The 7 hour rider is probably a slower swimmer, starting the ride between 8:30 and 9 has only an hour or so of cool morning temps before the heat starts to climb, then has 6 hours of riding in the heat of the day. By Noon, the pavement will be reflecting even more heat onto the rider and they still have another 3 hours to go. Sweat city!
There could also be more cooling effect at 20-22 MPH vs 15 MPH… that could keep core temperatures down and reduce sweat volume.
Faster racers are also likely more experienced and have a good knowledge of how to fuel/hydrate, as well as how to maintain a steady pace keeping core temps more consistent.
just a thought while reading the responses, note proven but, maybe the people (faster) that you don’t see with salt stains because they have continued to sweat the whole time. Meaning they got in enough fluids to keep sweating rather then getting dehydrated and not sweating anymore. Once you stop sweating or slow down and you kit dries you see the salt lines. If you continue to sweat you keep it wet and don’t see the salt lines.
I like the way you think. I was thinking something similar, along the lines that the concentration of sodium/water becomes high and the gut starts raiding muscle tissue for additional water to process the excess. We see the effects as concentrated sweat on the skin and feel the effects as dehydration. And the response would be to consume more water relative to electrolytes (from Gatorade or salt tabs). But, I’m just making all that up and was hoping someone smarter than me would chime in with the physiological answer.
Probably some validity to this. For my sample size of one, I can tell you I have salt stains on great days as well as bad.
My primarily PHX based training means I’m producing some high volume sweat, but none of it is staying on my skin. Interesting to note that when I hit a higher humidity environment I have a lot of sweat on my skin and dripping off my head - much more than any of the locals, yet no salt stains visible, probably because of a still wet kit.
However, did the Triple Bypass on a pretty hot/dry day a couple of weeks ago and I was covered in salt stains. Kit was dry at the finish and felt great after 7.5 hours on the bike but a lot of salt. I don’t think it’s the best indicator of attacking when you see the salt as some might have said in the past, but if somebody is not taking in the fluids and their visible sweat diminishes, maybe there really is something to this.
For the slower competitors, they are out there longer and so are sweating out more salt to end up on their kits.
The faster competitors generate more watts (heat) and are therefore more likely to douse themselves with water to cool off, which also helps wash away the salt.
There may also be a link to the fact that heavier sweaters are probably more likely to have salt stains and are also more likely to run into dehydration issues as the race progresses. Sweat rates within the population differ in about a 3:1 range.
