Salty Sweat Stains: Why They Happen and Are They Preventable?

Salt-stained kits: some riders get them, some don’t. So what gives?

In episode 51 of the Ask a Cycling Coach, a rider submitted a question to the podcast asking if he could prevent salt buildup on his black kit. Compared to his buddies he rides with, he gets a lot of it and finds it to be a bit embarrassing.

Firstly — there’s no reason to be embarrassed about salt stains! It’s a sign of your hard work. Be proud of that. Secondly, you’ll soon learn the composition of your sweat is out of your control, which means any time spent worrying about your salty kit is, well, pointless.

To help explain why, our Head Coach Chad referenced Skratch Lab’s Dr. Allen Lim 2015 Endurance Coaching Summit video in the podcast. Here are the key points Lim shared in his presentation:

Why We Lose Salt When We Sweat

Sweat loss is a type of dehydration that happens when you exercise or experience a heat load. When you sweat, all that fluid comes from inside your bloodstream. Any electrolyte loss that occurs is a reflection of what’s in your bloodstream. The electrolyte content of your bloodstream is almost entirely sodium-chloride — that’s the fancy term for table salt. When we say “almost entirely,” we’re talking roughly 90 percent of our electrolyte loss through sweat is table salt.

Everyone Loses Different Amounts of Salt When They Sweat

Not everyone loses the same amount of salt when they sweat! Sweat sodium is extremely variable when you compare person to person. Some athletes lose as little as 300-400 milligrams per liter of sweat, whereas other might lose as high as 2,000 milligrams per liter of sweat. The primary reason for this is genetics. Genetics, above all else, play the largest role in determining how salty your sweat is.

While there’s nothing you can do about genetics, there are a handful of outside factors that can marginally affect how much salt you lose when you sweat.

Sweat rate — I.e. how fast your body releases sweat from its glands. When you sweat less, you lose less salt. Sweat rates can get as high as 4 liters/hour depending on your environment, the intensity of the exercise you’re doing and your body’s shape and size. If you’re a tall and slim person, your body does not need to sweat as much to cool itself compared to someone with a shorter, stockier build. This could mean you find your kit to be far less salty (if salty at all) than your riding partner’s kit.

Adding to the list of things that affect sweat rate is your fitness. Different levels of fitness lead to quicker and more profuse levels of sweating. This reason for this is our bodies get better at thermoregulation as we become fitter. Some riders will notice at the start of their training after time of the bike it can take them most of their warm up to work up a sweat. Once they’re reasonably race-fit, however, they’ll start sweating in the opening five minutes or so of ride, despite how easy their workout may be.

Sodium intake — This one’s straightforward. The more sodium-rich foods and drinks you consume, the more sodium loss you’ll experience.

Heat acclimatization — When your body adjusts to the heat conditions, your sweat naturally becomes more dilute.

Gender — Females tend to lose less sodium than males. This could be because men tend to have a higher sweat rate.

How to Determine How Salty of a Sweater You Are

If you’re curious to learn how much sodium your sweat contains, there are a couple tests you can take. The first is the patch test, also referred to as a sweat test. Most commonly used to test for cystic fibrosis, the sweat test uses a piece of gauze to grab a sample of a person’s sweat. Once the sample is taken, it is weighed and measured for salt chemicals.

A more advanced method to analyze sweat for sodium is to use a Macroduct collection system. This is what Lim and his team at Skratch Labs use. This method produces more accurate results as it ensures there is no evaporative loss in the test process.

Conclusion

It turns out the those salty sweat stains on your kit are not preventable. You’re either a super salty sweater or you’re not. You can thank genetics mostly for that. In either case, don’t sweat it! (Yup, that pun was intended.)

Listen to Experts Discuss This Training Topic and More on the Ask a Cycling Coach Podcast

The cycling experts at TrainerRoad discussed why some riders experience salty bibs on last episode 51 of the Ask a Cycling Coach podcast. Listen below to hear exactly what they had to say.

Additional Notes

TrainerRoad’s Ask a Cycling Coach podcast is dedicated to making you a faster cyclist. It gives you the chance to get answers to your cycling and triathlon training questions from USAC certified coaches Chad Timmerman, Jonathan Lee and special guests. Learn more about other topics we covered in the latest episode with our resources below:

• Body fat analysis
• How to measure your body composition
• What is the best way to lose fat
• How to lose fat and gain muscle
• How do you compare to Chris Froome?
• Chris Froome’s VO2 Max, FTP and power to weight ratio
• Does poor quality sleep affect performance?
• Why measuring your training with mileage is pointless
• What is the best way to measure your training
• Why isn’t your training plan making you faster?
• What to do if you feel fatigued
• Which earbuds / headphones are best for indoor training
• Do aging athletes have to adjust their training plans?
• How to adjust your training for your age
• What does excessive salt buildup from sweat mean?
• Are salty sweat stains bad?
• How to use a smart trainer to warmup at a race
• How do you know when to start a race hard or go easy?
• Why positioning is so important in racing
• What course features or characteristics make positioning critical
• How to position yourself well in a race
• How to pace after a hard start
• Different ways to train for cyclocross

If you have a question that you’d like to ask Coach Chad, submit your question here. We’ll do our best to answer it on the next episode of the Ask a Cycling Coach podcast.