By Sebastian Madlangbayan, founder of Cleonse: the world's cleanest 3-ingredient organic electrolyte.
Your hourly sodium loss is sweat rate multiplied by sweat sodium concentration — nothing more complicated than that. Across 1,303 tested athletes, endurance athletes averaged about 1,190mg of sodium lost per hour, baseball players about 630mg. The range within any single sport is wider than the gap between sports.
That last sentence is the whole problem with sodium advice. Everyone wants a number, and the honest answer is that the population average tells you very little about you specifically.
So let's do the math properly, then talk about what dose actually makes sense in practice.
The equation
There is only one:
Sweat rate (L/hour) × sweat sodium concentration (mg/L) = sodium lost per hour (mg)
Two inputs. Both measurable. Both highly variable between people.
Input one: your sweat rate
Sweat rate is the easy one, because you can measure it yourself in an afternoon.
Weigh yourself naked before a workout. Do the workout. Track how much fluid you drink. Weigh yourself naked afterward, toweled off. Then:
Sweat rate = (pre-weight − post-weight + fluid consumed) ÷ hours
One kilogram of body mass lost is approximately one liter of sweat. Do this two or three times in different conditions — a cool morning, a hot afternoon — and you'll know your range.
For reference, here is what measured whole-body sweating rates look like across 1,303 athletes, from Baker and colleagues' 2019 normative dataset published in the Journal of Sports Sciences:
| Sport | Mean sweating rate | Standard deviation |
|---|---|---|
| American football | 1.51 L/h | ± 0.70 |
| Endurance sports | 1.28 L/h | ± 0.57 |
| Basketball | 0.95 L/h | ± 0.42 |
| Soccer | 0.94 L/h | ± 0.38 |
| Baseball | 0.83 L/h | ± 0.34 |
Look at the standard deviations. An American football player one standard deviation below the mean sweats less than an endurance athlete one standard deviation above. Sport is a weak predictor. Individual physiology and conditions are strong ones.
Input two: your sweat sodium concentration
This one you can't easily measure at home. It requires a sweat test — either a patch-based field test or a lab measurement.
Precision Fuel & Hydration, drawing on a database of over 30,000 tests, reports a range of roughly 200 to 2,300 mg of sodium per liter of sweat, with a typical athlete around 950 mg/L. That's more than a tenfold spread between the saltiest and least salty sweaters.
Unlike sweat rate, this number is relatively stable for you as an individual. It's substantially genetic, shifts somewhat with heat acclimation, and doesn't change much day to day. Which means it's worth measuring once.
If you haven't tested, there are rough clues. Visible white salt crusting on your skin, hat, or dark clothing after a hard session suggests you're toward the higher end. Sweat that stings your eyes badly or tastes distinctly salty points the same direction. These are weak signals, not measurements, but they're better than nothing.
The calculator table
Find your sweat rate down the side, your sodium concentration across the top. The cell is your hourly sodium loss in milligrams.
| Sweat rate ↓ / Sweat sodium → | 400 mg/L (low) | 950 mg/L (average) | 1,500 mg/L (salty) | 2,000 mg/L (very salty) |
|---|---|---|---|---|
| 0.5 L/h (light, cool) | 200mg | 475mg | 750mg | 1,000mg |
| 1.0 L/h (moderate) | 400mg | 950mg | 1,500mg | 2,000mg |
| 1.5 L/h (hard or hot) | 600mg | 1,425mg | 2,250mg | 3,000mg |
| 2.0 L/h (very hard, hot) | 800mg | 1,900mg | 3,000mg | 4,000mg |
| 2.5 L/h (extreme) | 1,000mg | 2,375mg | 3,750mg | 5,000mg |
The spread across that table is 25-fold. Anyone who tells you athletes need "X milligrams per hour" without asking about you is guessing.
What the measured data says by sport
Baker's dataset also reports the rate of sweat sodium loss directly. Converting from millimoles to milligrams (multiply by roughly 23):
| Sport | Sodium loss rate | In milligrams per hour |
|---|---|---|
| American football | 55.9 ± 36.8 mmol/h | ~1,290mg/h (range ~440–2,130) |
| Endurance | 51.7 ± 27.8 mmol/h | ~1,190mg/h (range ~550–1,830) |
| Soccer | 34.6 ± 19.2 mmol/h | ~800mg/h (range ~355–1,240) |
| Basketball | 34.5 ± 21.2 mmol/h | ~795mg/h (range ~305–1,280) |
| Baseball | 27.2 ± 14.7 mmol/h | ~625mg/h (range ~290–965) |
Those parenthetical ranges are one standard deviation either side of the mean, meaning roughly two thirds of athletes fall inside them. A third fall outside.
Losing sodium is not the same as needing to replace it
This is where a lot of electrolyte marketing quietly overreaches, mine included if I'm not careful.
You do not need to replace 100% of your sodium losses during the activity. Several things make this true:
Most people already eat plenty of sodium. The average Western diet supplies well over 3,000mg a day. For a one-hour workout losing 800mg, your next two meals cover it without you doing anything deliberate.
Duration is what matters, not intensity. A brutal 45-minute session might cost you 700mg. A six-hour easy ride in the heat might cost you 5,000mg. The second one requires a plan; the first one requires a sandwich.
Modest dehydration is well tolerated. The exercise-associated hyponatremia literature notes that up to about 3% body mass loss during exercise is well tolerated by most people.
And critically: sodium supplementation does not prevent hyponatremia. This is the most important correction to the popular narrative. The 2017 update on exercise-associated hyponatremia in Frontiers in Medicine is direct about it — "it is the amount of fluid ingested rather than the amount of sodium ingested during exercise that drives the final blood sodium concentrations." A study of a 161 km race found sodium supplementation made a "minimal contribution" to preventing hyponatremia, and one athlete developed it despite consuming considerable supplemental sodium.
The practical implication: the dominant risk in long events is drinking too much fluid, not eating too little salt. Drinking to thirst is the strategy the researchers recommend. Sodium helps you retain what you drink and makes you want to drink it, which is genuinely useful. It is not a shield against overdrinking.
So how much do you actually need per bottle?
Here's where the concentration argument matters more than the absolute dose, and where I think a lot of the category has drifted in an unhelpful direction.
The Gatorade Sports Science Institute's review of beverage formulation lays out three thresholds from the rehydration literature:
- At or above 20–30 mmol/L — fluid retention is significantly improved versus low- or no-sodium drinks. Below this, you're largely making urine.
- 18–40 mmol/L — this range "improves beverage palatability and increases ad libitum fluid intake." You drink more of it, voluntarily.
- At or above 50 mmol/L — "palatability and voluntary fluid intake may decrease." Too salty, and people stop drinking it.
That third point is the one that gets ignored. A rehydration drink only works if you finish it.
Here's where real products land when you convert their sodium content into a concentration:
| Product | Sodium | Water | Concentration | Zone |
|---|---|---|---|---|
| Plain water | 0mg | — | 0 mmol/L | No retention benefit |
| Gatorade Thirst Quencher stick | 230mg | 16.9 oz | ~20 mmol/L | Bottom of retention range |
| Powerade | 240mg | 12 oz | ~29 mmol/L | Effective, palatable |
| Skratch Labs Hydration | 400mg | 16 oz | ~37 mmol/L | Effective, palatable |
| Cleonse | 500mg | 16 oz | ~46 mmol/L | Effective; top of palatable band |
| High-dose products | 1,000mg | 16 oz | ~92 mmol/L | Above the palatability threshold |
A 1,000mg-per-16-oz product is roughly twice the concentration at which the literature says voluntary intake starts to fall off. That does not make it a bad product — it makes it a concentrate. If you're a genuinely salty sweater losing 2,500mg an hour, you need that much sodium and getting it in one stick is efficient. But you should probably be putting it in more water than 16 oz, and many people who use these products at full strength find them unpleasantly salty for exactly the reason the research predicts.
This is the reasoning behind 500mg per 16 oz. It clears the retention threshold with room to spare. It sits just under the point where palatability starts working against you. And it's a dose you can stack: two sticks across a three-hour session in the heat is 1,000mg, spread over 32 oz of fluid, which is a sane way to hit a high number without drinking anything that tastes like seawater.
It is a mid-range dose, deliberately. If you need 2,000mg in a single bottle, Cleonse is the wrong product and I'd rather tell you that than sell you four sticks.
When you genuinely need more
Situations where the higher-dose products earn their place:
- Confirmed salty sweater — a sweat test putting you above roughly 1,200 mg/L
- Sessions over three hours in heat, where cumulative losses run into the thousands of milligrams
- Heat acclimatization week — the first several days in a new hot climate, before your sweat glands adapt and start conserving sodium
- Back-to-back training days where you never fully replaced yesterday's losses
- Very low-carb or ketogenic diets, which increase renal sodium excretion independently of sweat
- A history of heat cramps that correlate with long, salty sessions
And situations where you need less than the internet suggests:
- Workouts under an hour
- Indoor training in air conditioning
- Cool-weather sessions where you barely sweat
- Any day you're eating normally and not doing anything unusual
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Shop CleonseFrequently asked questions
How do I calculate how much sodium I lose per hour? Multiply your sweat rate in liters per hour by your sweat sodium concentration in milligrams per liter. Measure sweat rate by weighing yourself before and after a session, adding back any fluid consumed, and dividing by the duration. Sweat sodium concentration requires a sweat test; the population range is roughly 200 to 2,300 mg/L with an average around 950 mg/L.
How much sodium should an athlete consume per hour of exercise? There is no single number. Measured sodium loss rates average around 1,290mg per hour for American football players and 625mg per hour for baseball players, with roughly a third of athletes falling outside one standard deviation of their sport's mean. For sessions under an hour, your normal diet generally covers it. For long sessions in heat, matching a meaningful fraction of measured losses makes sense.
Is 500mg of sodium enough for a workout? For most sessions of one to two hours at moderate sweat rates, yes. At 500mg per 16 oz you are at roughly 46 mmol/L, comfortably above the 20 to 30 mmol/L threshold at which fluid retention improves, and below the 50 mmol/L point where palatability and voluntary intake begin to decline. For very long sessions or confirmed salty sweaters, you would stack servings or use a higher-dose product.
Do I need 1,000mg sodium electrolytes? Only if your measured losses justify it. A 1,000mg dose in 16 oz is about 92 mmol/L, roughly twice the concentration at which the research suggests people start drinking less. High-dose products suit confirmed salty sweaters and very long efforts, and they work better diluted into more water than a single 16 oz bottle.
Can too much sodium hurt athletic performance? Excess sodium in a drink mainly hurts by making it unpalatable, so you drink less and end up more dehydrated than if you had used a moderate concentration. Sodium supplementation also does not protect against exercise-associated hyponatremia, which is driven primarily by overconsumption of fluid. If you have high blood pressure or kidney concerns, discuss sodium intake with your doctor.
Does sweat sodium concentration change with training? Somewhat. Heat acclimation improves sodium conservation, so a well-acclimatized athlete typically loses less sodium per liter of sweat than the same athlete in their first days of heat exposure. But the large differences between individuals are substantially genetic and persist regardless of fitness, which is why a sweat test is worth doing once.
Cleonse: 500mg sodium and 26g carbohydrate from organic cane sugar in 16 oz of water — a mid-range dose you can stack across a long session. Three ingredients, nothing else. $33 for 10 sticks, $66 for 30, $110 for 60, free shipping, 30-day guarantee. See the product.
Editor's note and sources
I make Cleonse, a 500mg-sodium electrolyte, so I have an interest in arguing that a mid-range dose is sensible. I've tried to show the reasoning and the thresholds so you can check it. Normative sweat figures are population data and will not match any individual — measure your own sweat rate, and get a sweat test if the number matters to you. Millimole-to-milligram conversions use approximately 23 mg of sodium per millimole and are rounded. Competitor figures were read from current public product pages in July 2026.
- Baker L.B. et al., "Normative data for sweating rate, sweat sodium concentration, and sweat sodium loss in athletes: An update and analysis by sport," Journal of Sports Sciences 2019 (1,303 athletes), via GSSI: https://www.gssiweb.org/research/article/normative-data-for-sweating-rate-sweat-sodium-concentration-and-sweat-sodium-loss-in-athletes-an-update-and-analysis-by-sport
- Baker L.B., "Sweating Rate and Sweat Sodium Concentration in Athletes: A Review of Methodology and Intra/Interindividual Variability," Sports Medicine 2017: https://link.springer.com/article/10.1007/s40279-017-0691-5
- Sweat sodium concentration range and estimation method, Precision Fuel & Hydration: https://www.precisionhydration.com/performance-advice/hydration/how-to-estimate-sweat-salt-loss/
- Beverage sodium concentration thresholds for fluid retention and palatability, Gatorade Sports Science Institute, Sports Science Exchange: https://www.gssiweb.org/sports-science-exchange/article/the-fluid-replacement-process-principles-of-beverage-formulation-for-athletes
- Hew-Butler T. et al., "Exercise-Associated Hyponatremia: 2017 Update," Frontiers in Medicine: https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2017.00021/full
- Skratch Labs Hydration Sport Drink Mix: https://www.skratchlabs.com/products/hydration-sport-drink-mix
- LMNT ingredients and nutrition: https://drinklmnt.com/pages/ingredients
Nothing here is medical advice. Cleonse supports hydration; it does not treat, cure, or prevent any condition. If you have high blood pressure, kidney disease, or are on a sodium-restricted diet, talk to your doctor before increasing sodium intake.