You drank the water. Three liters of it. You still feel foggy, flat, and vaguely headachy at 3pm.

So you buy the packets. The colorful ones. And now you're drinking salt water that costs more per serving than coffee.

Here is the uncomfortable part. Most people buying electrolytes do not need them. And some of the people who genuinely do need them are the ones still refusing, because they read a headline that said sports drinks are sugar bombs.

Both groups are getting it wrong for the same reason. They're asking "electrolytes or water?" when the real question is "what am I actually losing?"

What an electrolyte actually is (30 seconds, then we move on)

Electrolytes are minerals that carry an electrical charge when dissolved in fluid. Sodium, potassium, chloride, magnesium, calcium.

They do three jobs that matter to you:

  • They decide where water sits in your body. Sodium pulls water into the space outside your cells.
  • They fire your nerves. No charge gradient, no signal.
  • They contract your muscles. Including the one in your chest.

Water alone has no charge. Drink enough of it fast enough with nothing else, and you dilute the charge that's already there. That's the whole mechanism behind every scary marathon story you've heard.

The contrarian bit: sodium is not the problem for most people

The wellness internet has convinced a lot of people they are "depleted." Depleted of what, exactly?

USDA national survey data put average sodium intake in the US at 3,330 mg a day, against a recommended ceiling of 2,300 mg. Over 75% of adult men and over 50% of adult women exceeded that ceiling on the day they were surveyed.

Most people are already over the line. Before they add a packet.

If you work at a desk, walk to lunch, and lift three times a week in an air-conditioned gym, your sodium ledger is not in deficit. Your food is doing the job. Adding an electrolyte drink is not fixing a deficiency. At best it makes water taste like something, which makes you drink more of it, which was the actual problem.

The mineral most people are genuinely short on is the one nobody sells in a stick pack. Potassium. The Adequate Intake is 3,400 mg/day for men and 2,600 mg/day for women. In the same national survey data, only around a quarter of men aged 20 and over hit 3,400 mg on the reporting day, and most other groups came in under 2,600 mg.

That gap gets closed with potatoes, beans, yogurt and bananas. Not sachets.

Now the other side: who genuinely needs them

This is where the "just drink water" crowd loses the plot.

Sweat is not water. Sweat is salty water, and how salty varies enormously between humans.

A large normative dataset of 1,303 athletes compiled by Baker and colleagues found average whole-body sweat rates of 1.51 L/h in American football players and 1.28 L/h in endurance athletes. Sodium losses averaged around 51.7 mmol/h in the endurance group. The headline finding was not the average. It was the spread. Individual variation was enormous across every single sport.

Translation: two people running the same race in the same heat can lose wildly different amounts of salt. One finishes fine on water. The other finishes with white crust on their temples and a cramping calf.

You are one of those two people. You don't get to choose which.

The five situations that actually call for electrolytes

  1. Exercise over 60-90 minutes, especially in heat. The ACSM position stand on exercise and fluid replacement states that beverages containing electrolytes and carbohydrates can provide benefits over water alone under certain circumstances, and that because sweat rates and sweat electrolyte content vary so much between individuals, fluid replacement programs should be customised rather than standardised.
  2. Heavy sweating in hot work. Roofers, kitchen staff, warehouse workers in July. Multiple liters of sweat per shift, day after day.
  3. Vomiting or diarrhea. This is the original, best-evidenced use case. It's why oral rehydration solution exists.
  4. You're a salty sweater. Visible salt streaks on your face and clothes, stinging eyes, gritty skin after drying.
  5. You're deliberately restricting. Low carb, keto, aggressive fasting, or a very low-sodium whole-foods diet. Cutting processed food cuts sodium hard, and the first week feels like flu for exactly that reason.

Notice what's missing from that list. "Woke up tired." "Had a stressful week." Those are not electrolyte problems.

The thing that actually hurts people: too much water, not too little salt

Here's the part the marketing skips.

In the 2005 New England Journal study of Boston Marathon runners, 13% of finishers had hyponatremia — blood sodium at or below 135 mmol/L. Roughly 0.6% were in critical territory. The strongest predictors were substantial weight gain during the race, long finishing times, and body-mass-index extremes.

Weight gain. During a marathon. That means they drank more than they lost.

And the 2017 update to the international consensus statement on exercise-associated hyponatremia is blunt about the fix: it's the volume of fluid ingested, not sodium intake, that drives final blood sodium. Sports drinks are hypotonic. They will not save someone who is overdrinking.

So the sports drink you bought as insurance is not insurance. Drinking to thirst is.

Why oral rehydration solution works and flavored water doesn't

If you've ever wondered why a proper rehydration sachet works differently to a sports drink, the answer is a co-transporter in your gut wall.

Sodium and glucose get absorbed together across the intestinal lining. Water follows them by osmosis. Get the ratio right and absorption is fast and near-complete. Get it wrong and you've just made expensive urine.

WHO's reduced-osmolarity oral rehydration salts formula delivers 75 mmol/L sodium, 75 mmol/L glucose and 20 mmol/L potassium at a total osmolarity of 245 mOsm/L. That precise pairing is why ORS is one of the highest-impact medical interventions of the last century.

Most commercial "electrolyte water" has a trace of sodium and no functional glucose. It's flavored water with a health claim on the label. That's fine. Just know what you bought.

Do this today: the two-week sweat audit

You don't need a lab. You need a scale and two weeks of paying attention.

This is the method the ACSM position stand itself points to: individual sweat rates can be estimated by measuring body weight before and after exercise.

Step 1 — Weigh naked before a hard session. Same scale, same conditions.

Step 2 — Train. Track every drop you drink. Write it down. A 500 ml bottle finished is 500 ml.

Step 3 — Towel off, weigh naked again.

Step 4 — Do the math. Sweat loss (litres) = (weight before minus weight after, in kg) + fluid drunk in litres.

Example: down 1.0 kg, drank 0.5 L. You sweated 1.5 L that session.

Step 5 — Divide by session hours. That's your sweat rate per hour. Under 0.8 L/h in normal conditions, you are not a heavy sweater. Over 1.5 L/h, you are.

Step 6 — Check the salt signals. After three sessions, look for white residue on a dark shirt or hat brim, sting in the eyes, grit on the skin. Present across all three, plus a high sweat rate, means you're a salty sweater and electrolytes earn their place.

Step 7 — Apply the rule. Sessions under an hour: water. Sessions over an hour, or heavy sweat rate, or hot conditions: add sodium. Everything else: food does it.

Repeat once in winter and once in summer. Your sweat rate is not a fixed number.

The tracking part is the part people abandon. That's the honest reason most hydration plans fail — not knowledge, admin. WaterDrop exists to make the logging take two seconds instead of two minutes, so the audit actually gets finished rather than started.

How much sodium, if you decide you need it

Rough working numbers, not prescriptions:

Situation Sodium target
Under 60 min, moderate 0 mg — water is fine
60-120 min, moderate sweat 300-600 mg per litre consumed
2+ hours, heavy or salty sweater 700-1,200 mg per litre
Vomiting/diarrhea recovery Proper ORS sachet, follow the label
Keto/fasting adaptation week 1,000-2,000 mg/day extra, from food or broth

Start at the low end. Salt intake is easy to overshoot and the feedback is instant — you get thirsty and bloated.

And note the units. Sodium is not salt. One gram of table salt contains about 390 mg of sodium. If a label says "salt," multiply by roughly 0.4 to get sodium.

Does dehydration actually hurt performance, or is that marketing too?

Reasonable question, and the science is less settled than sports drink ads suggest.

The traditional line is that losing more than 2% of body mass impairs endurance. A blinded study by James and colleagues — where subjects couldn't tell which condition they were in — did find lower work output at around 2.4% body mass loss, along with higher heart rate and perceived exertion.

But a methodological review in Sports Medicine argues much of the earlier literature was confounded, because the ways researchers induce dehydration are uncomfortable and unfamiliar in themselves.

Practical read: real dehydration does cost you something, especially in heat. The cost is smaller than the industry implies. And it kicks in at losses most gym-goers never reach.

If you want the deeper mechanism on why water matters day to day, we covered it in the science of hydration. If you keep feeling parched no matter what you drink, this one is the better read.

Cramps: the claim that sells the most packets, and the weakest evidence

Ask ten gym-goers why they take electrolytes. Most say cramps.

The problem is that the cramp story never held up under scrutiny. A review in the British Journal of Sports Medicine by Schwellnus examined the three competing explanations for exercise-associated muscle cramps and found that support for the dehydration and electrolyte-depletion theories came mainly from anecdote, clinical observation and case series. Four prospective cohort studies did not support them.

The explanation with actual experimental backing is altered neuromuscular control. Cramps appear to come from an imbalance between excitatory signals from muscle spindles and inhibitory signals from Golgi tendon organs, driven by fatigue — especially when a muscle contracts in a shortened position.

Which matches what every cramping athlete already knows. Cramps hit late, in the muscle you overworked, in the position where it's already shortened.

That doesn't make electrolytes useless. It makes them the wrong tool for this one job. If you cramp at hour four of a race, the honest answers are that you went out too hard, you're undertrained for that distance, or you're doing something in a shortened range. More salt won't fix any of those. Neither will more water.

The tiredness you blamed on electrolytes

Let's name the thing that sent you searching in the first place.

The 3pm crash. The headache. The heavy legs.

Electrolytes get blamed because it's a satisfying explanation with a purchasable fix. But the crash is far more often under-eating at breakfast, six hours of shallow breathing at a desk, poor sleep the night before, or genuinely just not drinking enough plain water since 8am.

Test the boring explanations first. They're free. If you fix your total daily intake and the fog persists through a hot week of training, then yes, look at sodium.

Get your baseline number first — the daily water intake calculator gives you a starting target based on your size and activity rather than the recycled eight-glasses myth.

FAQ

Do I need electrolytes if I just drink a lot of water? Only if you're drinking so much you're diluting yourself, and that's rarer than the internet suggests. If your urine is consistently clear as tap water and you're up at night to pee, you're overdoing volume. Cut the water before you add salt.

Are electrolyte drinks better than water for a hangover? Somewhat, but not for the reason people think. Alcohol suppresses vasopressin, so you lose fluid and sodium through urine overnight. A rehydration solution replaces both, which beats plain water. It does not touch the acetaldehyde that causes most of the misery.

Can you take too many electrolytes? Yes. Excess sodium raises blood pressure in salt-sensitive people, and potassium supplements can be genuinely dangerous for anyone with reduced kidney function or on certain blood pressure medications. Food-based potassium is safe. High-dose pills are a conversation with a doctor, not a shopping decision.

Should I drink electrolytes every day? For most people, no. Daily use makes sense if you're sweating heavily most days, working in heat, on a very low-carb diet, or recovering from illness. Otherwise you're paying a subscription for something your dinner already provides.

What about coconut water or a pinch of pink salt? Coconut water is high in potassium and low in sodium, so it's a decent recovery drink and a poor sweat replacement. Pink salt is sodium chloride with trace minerals in amounts too small to matter nutritionally. Use it because you like it, not because it's medicinal.

How do I know if I'm a salty sweater without a lab test? Wear a dark shirt for a long hot session and look for white crust after it dries. Add stinging eyes, gritty skin, and food tasting bland afterward. Three or four of those signs together is a strong signal, and it's the same screen the sweat-test companies use before they sell you the test.

The one thing to take away

Water fixes volume. Electrolytes fix concentration. Almost nobody has a concentration problem until they've been sweating hard for over an hour — so fix the boring one first, and let your sweat rate tell you whether the second one is even your problem.

If the honest blocker is that you never track any of it long enough to see a pattern, WaterDrop takes the friction out of the logging so the data collects itself.

— Dolce