Are You a Salty Sweater? 5 Signs and How to Adjust Your Fuelling

You finish a hard summer ride, glance down at your bib shorts and find a white, gritty tide-mark across the black Lycra. Your eyes sting, your lips taste like a bag of crisps, and your helmet straps look like they've been dipped in the sea. If that sounds familiar, there's a good chance you're a salty sweater, and it matters more for your fuelling than most athletes realise.

Sweat isn't just water. It carries sodium, chloride and smaller amounts of potassium and magnesium, and the concentration varies enormously from person to person. Research puts average sweat sodium at around 900 mg per litre, but individuals range from roughly 200 mg/L to well over 1,800 mg/L. Two riders losing a litre an hour can be losing very different amounts of salt, and a one-size-fits-all drink mix simply won't cut it for both of them.

5 Signs You Might Be a Salty Sweater

None of these is proof on its own, but if you tick three or more, it's worth taking seriously.

• White salt marks on kit or skin. Once the water evaporates, the sodium stays behind. Streaks on your jersey, a crust on your forehead or a gritty feel on your face after a session are the classic giveaway.
• Stinging eyes and a salty taste. If sweat running into your eyes burns far more than it does for your training partners, or you can taste salt on your lips mid-session, your sweat is likely concentrated.
• Cramping late in long sessions. The evidence on cramp is mixed and fatigue plays a big part, but heavy sodium losses combined with plain water intake is a common pattern in athletes who cramp repeatedly in the heat.
• Craving salty food afterwards. Reaching for crisps, olives or a bag of salted chips after a long day out isn't always a weakness. Sometimes it's your body asking for sodium.
• Feeling flat despite eating and drinking plenty. Sloshing stomach, headaches or a sudden drop in pace after hours of drinking plain water can point to sodium being diluted rather than replaced.

How to Find Out Properly

The gold standard is a sweat patch test, where a clinic collects sweat from your forearm and measures the sodium concentration. Several UK sports labs offer this for around £50–£100, and it's a one-off test, because your sweat sodium is fairly stable across your adult life, although heat acclimation can reduce it a little.

You can build a decent picture at home as well. Weigh yourself naked before and after a one-hour session at race intensity, noting any fluid you drank. Every kilogram lost is roughly one litre of sweat. Most endurance athletes sweat between 0.5 and 2 litres an hour, so if you lose 1.2 kg in an hour and drank 300 ml, your sweat rate is about 1.5 L/h. Multiply that by a rough sodium concentration (900 mg/L as a middle estimate, more if you tick the signs above) and you'll see how quickly the milligrams add up. At 1.5 L/h and 1,200 mg/L, you're shedding 1,800 mg of sodium an hour.

Adjusting Your Fuelling and Hydration

Once you know you're towards the saltier end, there are three levers to pull.

1. Add sodium to your drinks. General guidance for endurance events is 300–600 mg of sodium per hour, and heavy or salty sweaters in the heat often need 800–1,000 mg per hour. Start at the lower end and build up in training. Taste isn't a reliable guide: a drink that tastes salty and unpleasant at rest can taste fine when you're properly depleted.

2. Don't overdo the water. This is the one people miss. Replacing every gram of sweat with plain water can dilute blood sodium and, in extreme cases, lead to exercise-associated hyponatraemia, which is dangerous. A sensible target is to replace around 60–80% of your sweat losses over a long event, drinking to thirst as a sanity check, and pairing fluid with sodium rather than water alone.

3. Keep carbohydrates separate from the salt. Your carbohydrate target (60–90 g an hour for longer events, depending on how well you've trained your gut) is a different job from your sodium target. Mixing the two into one bottle makes it hard to adjust either. Taking carbohydrates as solid or chewable fuel and sodium via your drink lets you tweak each independently when conditions change, and it spreads the load on your stomach.

It also pays to nudge your sodium up in the 24 hours before a hot race, with a salty meal and a pre-race drink, rather than starting the day already behind. Afterwards, rehydrate with fluid and food containing sodium. A normal meal with some salt is plenty for most people.

What We Use at FTP Endurance Fuel

We're a fuel company, not a magic-salt company, so we'll be straight about this: our pastilles are a carbohydrate source, and we don't pretend they replace your electrolyte drink. What they do is take the carbohydrate side of the equation off your bottle. Each pastille delivers a blend of glucose and fructose, so you can hit 60–90 g an hour without turning your drink into a thick, sugary syrup, and you can set your sodium concentration separately to match your sweat.

For long, hot days we like the Mixed Fruit Pastilles 1kg because the flavour variety helps when you're twelve hours in and the thought of one more sweet taste makes you grimace. The mild fruit flavours also sit better alongside a salty drink than something sharp or sticky. If you'd like to try before committing to a bulk bag, the Taster Pack is a low-risk way to test them in training.

Putting It Into Practice

One more practical point: heat acclimation changes the picture. After roughly ten to fourteen days of regular training in warm conditions, your body starts sweating earlier and holds on to more sodium, so your sweat becomes less salty even as your sweat rate climbs. That means a plan that works in July may need revisiting for a spring race in cooler weather, or for a holiday event in much hotter conditions than you've trained in.

Treat this as an experiment across a few weeks of training rather than a single big change. Run a sweat-rate test in cool conditions and again in warm ones, note the salt marks on your kit, then trial your sodium dose on long sessions at race pace. Log how you feel, whether cramps appear and how your pace holds in the final hour. Adjust by 200–300 mg an hour at a time rather than leaping to a huge number on race day.

If you recognise yourself as a salty sweater, you haven't got a problem, just a variable you can now manage. Get your sodium sorted, keep your carbohydrates steady and let your fuelling do the work. Ready to build a plan around it? Take a look at our bundles and stock up for your next big day out.