Do We Really Need Electrolytes? From Office Worker to Athlete, What the Evidence Shows
Open your browser and you'll likely find electrolyte sachets sold as a daily habit: stir one into your water at your desk, between meetings, before lunch. The pitch has quietly shifted from "athletes need this after a hard session" to "everyone needs this, every day". A wellness industry has been built on that shift, selling exercise-grade hydration to people whose heaviest workout is the walk to the printer.
Let's start with one statistic, from Singapore, and the pattern holds in many nations:
"Today, 9 in 10 Singapore residents consume more sodium than recommended... Over time, consuming too much sodium can increase your risk of high blood pressure, a major risk factor for heart disease and stroke. On average, Singapore residents consume around 3,620 mg of sodium a day, almost twice the recommended daily limit." Source: HealthhubSG
So do we need to be adding more electolytes - essentially salt (soduim chloride) to our diet?
As ever, please talk to your doctor or medical practitioner most familiar with your medical history before implementing any changes in diet, exercise or lifestyle, especially if you are under treatment. Links to studies / resources at bottom of page.
The short session: one hour in the heat
Killick and colleagues had twelve people cycle for 60 minutes in about 33 °C heat. Blinded and in random order, each person drank equal volumes of plain water, a sodium-potassium drink, or coconut water. Core temperature, heart rate, fatigue, and inflammation markers all climbed and body water dropped, but none of it differed by drink. Water performed as well as the engineered options.
The caveat: twelve people is small, "no difference" isn't the same as "equivalent," and recovery lasted only 90 minutes on modest 300ml doses. Still, for a one-hour session there is no sign that skipping the product cost anyone anything.
The long haul: five hours of running
McCubbin and da Costa had nine runners complete two five-hour treadmill runs at 30c. On one day they took salt capsules replacing 100% of their measured sweat sodium loss, on the other a placebo, drinking to thirst both times. If any scenario was going to show a big benefit, this was it. Yet sodium made no difference to heart rate, rectal temperature, perceived exertion, or fluid balance. Blood sodium rose in both conditions, a little more with salt, so runners drinking to thirst with no sodium weren't sliding toward low blood sodium.
Afterwards, the placebo group's kidneys held on to sodium (urinary loss of 21 vs 66 mmol), suggesting a large deficit is handled well. The salt group drank more over the next 24 hours (2.5 vs 2.0L), a real effect, but not a performance or safety win.
The long game: what salt does to the benefits of exercise
Exercise and eating less salt share a similar list of benefits: lower blood pressure and reduced risk of stroke, cardiovascular disease, osteoporosis, and dementia. Turner and Avolio asked whether sweating out sodium is part of how exercise works its magic.
The numbers make it plausible. Guidelines suggest 86 to 100 mmol of sodium a day, yet average intake exceeds 150. A session with sweat rates of 0.5 to 1.5L an hour costs about 20 to 90 mmol, the same size as the intake reductions linked with health benefits. The authors suggest that replacing sweat sodium may improve performance but blunt the long-term benefits of exercise. My sweat rate is 1.7L an hour when I run, higher when I ruck. Learn to measure your sweat rate, here.
They also float the idea that "salty sweaters" may be people with high intake who keep their sweat salty by constantly replacing what they lose. And they note that studies of prolonged, hard exercise in the heat suggest sodium supplementation isn't needed to prevent low blood sodium for up to six hours, which matches McCubbin and da Costa. The caveat: this is a hypothesis built from existing evidence, not a trial that tracked blood pressure or strokes over years.
The big picture: a systematic review
Veniamakis and colleagues reviewed sodium in endurance sport, and their conclusions are more measured than either the supplement industry or the "skip the salt" camp would like.
Sodium matters in both directions. It supports blood volume, nerves, muscles, and thirst. Too much is linked with high blood pressure and heart, kidney, and bone damage. Very low intake has also been linked with worse outcomes in observational studies, though people on low-sodium diets are often already unwell. The review settled on roughly 1.5g a day for everyday life.
Cramps and salt aren't as linked as we think. The review found no good evidence that sodium loss causes cramps. Muscle fatigue from going harder or longer than you're used to is the likelier culprit.
Low blood sodium is about how much you drink. Exercise-associated hyponatremia (blood sodium below 135 mmol/L) typically appears after four to six hours or more and has been tied to at least fourteen deaths. The main cause is overdrinking, often plain water, combined with the body retaining water it should release. Sodium can soften the drop in blood sodium but can't prevent it if you overdrink, and forced drinking should be discouraged.
Where guidance does recommend sodium. Major sports nutrition bodies recommend it for sweat rates above about 1.2 L an hour, noticeably salty sweaters, and efforts beyond two hours, with a commonly quoted target of 300 to 600 mg an hour. The review also notes that lab studies showing performance benefits always paired salt with drinking enough to match sweat losses, which may have helped create those benefits.
Reality check: what tropical runners actually lose
Surapongchai and colleagues measured 166 recreational runners in Thailand, running at their own pace for 30 to 100 minutes in about 30 °C and 70% humidity, drinking plain water as they pleased.
Sweat rates were substantial but not extreme. Men averaged about 1.3L an hour and women about 0.9, ranging from under 0.5 to nearly 4.
Most runners barely drank, and mostly got away with it. The average runner drank only 0.3L, and 15% of men drank nothing. Average body mass loss was about 1.2 to 1.3%, and only ten of 166 passed the 2% line that guidelines treat as the one to avoid.
Sodium losses were meaningful and very individual. Men lost about 54mmol an hour and women about 39 (roughly 1.2g and 0.9g of sodium, by my conversion). Sweat saltiness ranged from 11 to 80mmol per litre and didn't track with sweat rate, pace, or hydration, so you can't guess it from how hard you work.
Many people start behind. Before morning runs, 28% showed signs of hypohydration, against 15% in the evening.
The authors conclude that existing guidelines apply to heat-acclimatised tropical runners and that individualised strategies make sense. The caveats: a single snapshot per runner, sweat sodium estimated from a forearm patch, and plain water only, so it says nothing about electrolyte drinks.
It's not just sodium: what else is in your sweat?
Electrolyte products also advertise potassium, magnesium, calcium, and chloride. Whole-body sweat measured in a hot, humid environment contained about 51 mmol/L of sodium, 47 of chloride (which travels with sodium as salt), 4.8 of potassium, 1.3 of calcium, and 0.5 of magnesium. Sweating a litre an hour therefore costs roughly 190mg of potassium, 50 mg of calcium, and 12 mg of magnesium, against well over a gram of sodium (my conversion).
Daily needs run into the thousands of milligrams for potassium, around a thousand for calcium, and a few hundred for magnesium (typical reference values, which vary by country, age, and sex).
A normal diet covers the losses: bananas, potatoes, leafy greens, beans, nuts, seeds and dairy. A basic multivitamin can fill gaps, though it won't supply much potassium. And for an office worker who isn't sweating much, there is essentially little to replace.
So who's right?
The experiments and the guidance don't line up perfectly. The experiments found no benefit from added electrolytes on heat strain, fluid balance, or blood sodium. The review leans on guidelines and physiology to recommend sodium for long, sweaty efforts. Both can be true: sodium doesn't seem to cool you down or change how hard it feels, but may help with thirst, fluid retention and recovery after hours of heavy sweating.
Turner and Avolio are a reminder that more sodium isn't automatically better. The tropical data fit the experiments better than the marketing: most real-world sessions are under an hour, with little drinking and body mass loss under the 2% line.
What this means if you're rucking, running, or just sweating
Up to an hour or so: water is enough. Drink to thirst and eat your next meal. The tropical runners lost around a litre an hour, drank little, and mostly stayed within safe limits. Heat strain is handled by acclimatising, pacing, and cooling, not by what's in your bottle.
Start hydrated, especially for early sessions. The best-supported advice here is the boring kind. The Thai paper cites 5 to 10 ml per kg of body weight at least two hours before you start.
Beyond an hour: electrolytes becomes a sensible personal option, not a rule, for heavy sweaters, people finishing with salt-crusted kit, or anyone out for hours in the heat. Sports guidelines, which start at around two hours, point to 300 to 600 mg an hour. But how you drink matters more: drink to thirst, don't force fluids, and be wary of large volumes of plain water over many hours.
Here is roughly how much sodium is in table salt:
1/4 teaspoon = 600 mg of sodium
1/2 teaspoon = 1,200 mg of sodium
Source: American Heart Association
Don't chase cramps with salt, and don't guess your saltiness. The evidence linking sodium to cramps is thin, and sweat sodium varies hugely between people. You'd need a sweat test to know, and you don't need one to follow the basics above.
Think about the whole day. Most of your sodium comes from food. Trimming processed food probably matters more for your long-term health than anything you sip during a workout.
Final Thoughts
So do we all need to supplement electrolytes as the missing item in our daily nutritional mix? As we are told - sold online?
I think it's a grift, and the evidence is on my side. The research is almost entirely about people who are actually sweating, and even there the findings are far less dramatic than the marketing: water held up against electrolyte drinks after an hour in the heat, and a five-hour run in 30c showed no benefit to heat strain from replacing every milligram of sweat sodium. Meanwhile, most of us already eat more sodium than guidelines recommend.
Warning, while researching this article I clicked on one FaceBook advertisement for an electrolyte powder. Within a minute my feed was flooded with other such ads, from 5 other companies.
Do I use an electrolyte? Certainly not on a daily basis as I try to reduce salt in my diet. For running or rucking sessions - longer than an hour - I make a fruit cordial based beverage that has some mixed sugars and a sprinkle of salt. An effective way to hydrate in the heat and humidity, not simply to replace 'lost' electrolytes.
So before you pay a premium to add salt to your water, ask what problem you're solving, and who profits from convincing you that you have it. Our bodies have been managing fluid and salt for a very long time, and they're better at it than a label gives it credit for.
As always, the best health strategy is one you can stick with - one that fits your personal lifestyle profile. Improving health is about finding motivation, prioritising self-care and taking action. If you want to take effective and targeted steps to that fit into your unique lifestyle, The Whole Health Practice is here to help. Whether you want to improve eating practices, beat chronic illness or enhance your overall well-being, our consultations and programs deliver results that are tailored to your needs.
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Stay Healthy,
Alastair
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Related Studies
Killick JA, Jenkins EJ, Benson J, Macciochi J, Corr L. Comparing the Effects of Water, Sodium-Potassium, and Potassium-Rich Solutions on Fluid Balance and Thermal Strain Following Exercise in the Heat: A Randomized Triple-Blind Crossover Study. Int J Sport Nutr Exerc Metab. 2026 Aug 13:1-9. doi: 10.1123/ijsnem.2026-0016. Epub ahead of print. PMID: 42601056.
McCubbin AJ, da Costa RJS. Effect of Personalized Sodium Replacement on Fluid and Sodium Balance and Thermophysiological Strain During and After Ultraendurance Running in the Heat. Int J Sports Physiol Perform. 2023 Nov 9;19(2):105-115. doi: 10.1123/ijspp.2023-0295. PMID: 37944507.
Veniamakis E, Kaplanis G, Voulgaris P, Nikolaidis PT. Effects of Sodium Intake on Health and Performance in Endurance and Ultra-Endurance Sports. Int J Environ Res Public Health. 2022 Mar 19;19(6):3651. doi: 10.3390/ijerph19063651. PMID: 35329337; PMCID: PMC8955583.
Surapongchai J, Saengsirisuwan V, Rollo I, Randell RK, Nithitsuttibuta K, Sainiyom P, Leow CHW, Lee JKW. Hydration Status, Fluid Intake, Sweat Rate, and Sweat Sodium Concentration in Recreational Tropical Native Runners. Nutrients. 2021 Apr 20;13(4):1374. doi: 10.3390/nu13041374. PMID: 33923890; PMCID: PMC8072971.
Turner MJ, Avolio AP. Does Replacing Sodium Excreted in Sweat Attenuate the Health Benefits of Physical Activity? Int J Sport Nutr Exerc Metab. 2016 Aug;26(4):377-89. doi: 10.1123/ijsnem.2015-0233. Epub 2016 Feb 3. PMID: 26841436.
Other
Jiménez-Alfageme R, Garrone FP, Rodriguez-Sanchez N, Romero-García D, Sospedra I, Giménez-Monzó D, Ayala-Guzmán CI, Martínez-Sanz JM. Nutritional Intake and Timing of Marathon Runners: Influence of Athlete's Characteristics and Fueling Practices on Finishing Time. Sports Med Open. 2025 Mar 16;11(1):26. doi: 10.1186/s40798-024-00801-w. PMID: 40089940; PMCID: PMC11911277.
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