Mavr Sports Nutrition Team
Updated October 21, 2026. 14 min read.
Every start line has a runner swallowing a handful of salt tablets because a friend told them it stops cramps, and another runner who has never touched one and finishes covered in white streaks wondering why they faded in the heat. Both are guessing. Sodium is the one part of fueling where the right answer varies tenfold between runners, and the tablets only help if you are the kind of runner they are made for.
This guide tells you whether you are that runner, how much sodium you actually lose, what that means in tablets per hour, when tablets do nothing, and how to take them without turning a hydration plan into a stomach problem.
The word covers several different products, and the sodium per unit varies a lot. Salt is about 40 percent sodium by weight, so a tablet containing 1 g of salt gives you around 390 mg of sodium, which is the number that matters. Always read the sodium line, not the salt line.
Salt capsule (swallowed)
Typical sodium per unit200 to 250 mg
NotesMost common format; usually also potassium, magnesium, calcium in small amounts. Some brands offer 300 to 500 mg versions.
Buffered salt tablet (chewed or swallowed)
Typical sodium per unit200 to 400 mg
NotesCoated to be gentler on the stomach
Dissolvable electrolyte tablet (in a bottle)
Typical sodium per unit300 to 500 mg
NotesNot a salt tablet as such; you get the sodium only if you drink the whole bottle
High-sodium drink mix sachet
Typical sodium per unit500 to 1,500 mg
NotesThe strongest single dose available; designed for salty sweaters and heat
Energy gel
Typical sodium per unit20 to 200 mg
NotesVaries wildly by brand; check the label, some are almost sodium-free
Sports chews, per serving
Typical sodium per unit40 to 100 mg
NotesMinor contribution
Salted pretzels, 30 g
Typical sodium per unit350 to 450 mg
NotesReal-food option for ultras; needs water to get down
Table salt, 1/4 teaspoon
Typical sodium per unitAbout 575 mg
NotesThe cheapest salt tablet in existence, for a homemade drink
| Product | Typical sodium per unit | Notes |
|---|---|---|
| Salt capsule (swallowed) | 200 to 250 mg | Most common format; usually also potassium, magnesium, calcium in small amounts. Some brands offer 300 to 500 mg versions. |
| Buffered salt tablet (chewed or swallowed) | 200 to 400 mg | Coated to be gentler on the stomach |
| Dissolvable electrolyte tablet (in a bottle) | 300 to 500 mg | Not a salt tablet as such; you get the sodium only if you drink the whole bottle |
| High-sodium drink mix sachet | 500 to 1,500 mg | The strongest single dose available; designed for salty sweaters and heat |
| Energy gel | 20 to 200 mg | Varies wildly by brand; check the label, some are almost sodium-free |
| Sports chews, per serving | 40 to 100 mg | Minor contribution |
| Salted pretzels, 30 g | 350 to 450 mg | Real-food option for ultras; needs water to get down |
| Table salt, 1/4 teaspoon | About 575 mg | The cheapest salt tablet in existence, for a homemade drink |
Will you be running for more than 2 hours?
If yesSodium replacement is worth planning
If noSkip tablets. Salt your pre-run meal and move on.
Will it be hot, humid, or are you not yet heat-adapted?
If yesLosses go up sharply; add 200 to 300 mg per hour to your baseline
If noBaseline dose is enough
Are you a salty sweater? White streaks on kit, stinging eyes, craving salt after runs
If yesYou are likely above 1,000 mg/L and need the upper end of every range
If noYou are likely near or below average and the lower end will do
| Question | If yes | If no |
|---|---|---|
| Will you be running for more than 2 hours? | Sodium replacement is worth planning | Skip tablets. Salt your pre-run meal and move on. |
| Will it be hot, humid, or are you not yet heat-adapted? | Losses go up sharply; add 200 to 300 mg per hour to your baseline | Baseline dose is enough |
| Are you a salty sweater? White streaks on kit, stinging eyes, craving salt after runs | You are likely above 1,000 mg/L and need the upper end of every range | You are likely near or below average and the lower end will do |
Two yeses and you should have a plan. Three yeses and you should have tested it in training well before race day. No yeses and the money is better spent on gels.
Sodium loss is sweat rate multiplied by sweat sodium concentration, and both vary enormously. Sweat rates in runners range from about 0.5 to over 2 litres per hour depending on pace, heat, and body size. Sweat sodium ranges from roughly 200 to 2,000 mg per litre, with a typical value around 900 to 1,000 mg/L. Put those together and the hourly loss can be anything from 100 mg to more than 3,000 mg.
For a sense of what is normal: in a set of 506 athletes tested by the Gatorade Sports Science Institute, the average sweat rate was about 1.2 litres per hour, and estimated whole-body sweat sodium averaged about 36 mmol per litre, which is roughly 830 mg per litre. The spread was wide, from about 420 to over 1,600 mg per litre. That is why one dose does not fit everyone.
Find your row by sweat rate and your column by how salty your sweat is. Each cell shows how much sodium you lose per hour, and how much to take per hour on runs longer than about 2 hours. You do not need to replace all of it: the body handles a moderate sodium deficit over a few hours and corrects it at the next meal. The take-in range is about a third to two thirds of the loss, capped at roughly 1,200 mg per hour because that is where most stomachs stop coping with capsules.
0.6 L/h (cool, easy)
Low-salt sweat (about 500 mg/L)Lose 300, take 100 to 200 mg/h
Average sweat (about 1,000 mg/L)Lose 600, take 200 to 400 mg/h
Salty sweat (about 1,500 mg/L)Lose 900, take 300 to 600 mg/h
1.0 L/h (mild, steady)
Low-salt sweat (about 500 mg/L)Lose 500, take 150 to 350 mg/h
Average sweat (about 1,000 mg/L)Lose 1,000, take 350 to 650 mg/h
Salty sweat (about 1,500 mg/L)Lose 1,500, take 500 to 1,000 mg/h
1.5 L/h (warm, hard)
Low-salt sweat (about 500 mg/L)Lose 750, take 250 to 500 mg/h
Average sweat (about 1,000 mg/L)Lose 1,500, take 500 to 1,000 mg/h
Salty sweat (about 1,500 mg/L)Lose 2,250, take 750 to 1,200 mg/h
2.0 L/h (hot, racing)
Low-salt sweat (about 500 mg/L)Lose 1,000, take 350 to 650 mg/h
Average sweat (about 1,000 mg/L)Lose 2,000, take 650 to 1,200 mg/h
Salty sweat (about 1,500 mg/L)Lose 3,000, take 1,000 to 1,200 mg/h plus a high-sodium drink
| Sweat rate | Low-salt sweat (about 500 mg/L) | Average sweat (about 1,000 mg/L) | Salty sweat (about 1,500 mg/L) |
|---|---|---|---|
| 0.6 L/h (cool, easy) | Lose 300, take 100 to 200 mg/h | Lose 600, take 200 to 400 mg/h | Lose 900, take 300 to 600 mg/h |
| 1.0 L/h (mild, steady) | Lose 500, take 150 to 350 mg/h | Lose 1,000, take 350 to 650 mg/h | Lose 1,500, take 500 to 1,000 mg/h |
| 1.5 L/h (warm, hard) | Lose 750, take 250 to 500 mg/h | Lose 1,500, take 500 to 1,000 mg/h | Lose 2,250, take 750 to 1,200 mg/h |
| 2.0 L/h (hot, racing) | Lose 1,000, take 350 to 650 mg/h | Lose 2,000, take 650 to 1,200 mg/h | Lose 3,000, take 1,000 to 1,200 mg/h plus a high-sodium drink |
A cross-check from the American College of Sports Medicine: for exercise over an hour, it suggests about 500 to 700 mg of sodium per litre of fluid, with 600 to 1,200 ml of fluid an hour. That works out to about 300 to 840 mg of sodium per hour, which matches the middle of the chart. If you do not know your sweat rate yet, start in the average column and move once you have tested it.
How to find your row and column: weigh yourself before and after a 1-hour run, add what you drank, and you have your sweat rate. Our guide on how to test your sweat rate at home, linked at the end of this article, walks you through it step by step, and the calculator below does the arithmetic. For saltiness, white streaks on dark kit, stinging eyes, and salt cravings after long runs point to the salty column. A lab sweat patch test gives an exact number if you want one.
Use measurements from one representative workout. The formula accounts for drinks and any urine passed during the test.
A sweat-rate estimate is a planning input, not an instruction to replace every milliliter while moving. Avoid drinking enough to gain weight during exercise, and seek qualified medical advice for a history of hyponatremia, kidney or heart conditions, or heat illness.
Convert the target to tablets using the sodium per capsule on your label. The table assumes a standard 215 to 250 mg capsule and already accounts for the sodium you will get from gels and a typical sports drink, roughly 100 to 300 mg per hour.
Average sweater, cool weather, 2 to 3 hours
Sodium target300 to 500 mg/h
Salt capsules per hour0 to 1
AlsoGels and drink mix usually cover it
Average sweater, warm weather, 2 to 4 hours
Sodium target500 to 700 mg/h
Salt capsules per hour1 to 2
AlsoDrink to thirst; add sodium to the bottle
Salty sweater, cool weather, 2 to 4 hours
Sodium target600 to 800 mg/h
Salt capsules per hour2
AlsoPre-load with a salted meal 2 to 3 hours before
Salty sweater, hot weather, any distance over 2 hours
Sodium target800 to 1,200 mg/h
Salt capsules per hour3 to 4, or switch to a high-sodium drink mix
AlsoPre-load 500 mg with 500 ml of fluid 90 minutes before
Ultra, 6 hours or more, mixed conditions
Sodium target500 to 800 mg/h averaged
Salt capsules per hour1 to 3, alternating with salty real food
AlsoReassess every 2 hours; cravings and puffy fingers are signals
| Runner and conditions | Sodium target | Salt capsules per hour | Also |
|---|---|---|---|
| Average sweater, cool weather, 2 to 3 hours | 300 to 500 mg/h | 0 to 1 | Gels and drink mix usually cover it |
| Average sweater, warm weather, 2 to 4 hours | 500 to 700 mg/h | 1 to 2 | Drink to thirst; add sodium to the bottle |
| Salty sweater, cool weather, 2 to 4 hours | 600 to 800 mg/h | 2 | Pre-load with a salted meal 2 to 3 hours before |
| Salty sweater, hot weather, any distance over 2 hours | 800 to 1,200 mg/h | 3 to 4, or switch to a high-sodium drink mix | Pre-load 500 mg with 500 ml of fluid 90 minutes before |
| Ultra, 6 hours or more, mixed conditions | 500 to 800 mg/h averaged | 1 to 3, alternating with salty real food | Reassess every 2 hours; cravings and puffy fingers are signals |
The ceiling that matters is the stomach, not the kidneys. Above roughly 1,000 to 1,200 mg per hour, most runners get nauseous unless the sodium is spread through fluid rather than delivered in capsules. If you are in that territory, a high-sodium drink mix is the better tool.
People take salt tablets for three reasons, and the evidence supports only one of them.
Salt capsules
Best forPrecise dosing when you are drinking plain water from aid stations, or want sodium separate from carbohydrate
DrawbackEasy to overdo; useless without water; some runners find swallowing capsules while running hard
High-sodium drink mix
Best forSalty sweaters in heat; carrying your own bottle; combining fluid and sodium in one step
DrawbackTies sodium intake to fluid intake; limited by how much you carry
Standard sports drink
Best forRaces under 3 hours in mild weather; sodium arrives with carbohydrate and fluid
DrawbackUsually only 200 to 500 mg per litre, too little for salty sweaters or heat
Salty gels and chews
Best forTopping up during marathons without extra products
DrawbackSodium content is unpredictable between brands; rarely enough on its own
Salty real food
Best forUltras and long training runs; breaks the sweetness fatigue
DrawbackSlow to eat, needs water, hard to dose accurately
| Option | Best for | Drawback |
|---|---|---|
| Salt capsules | Precise dosing when you are drinking plain water from aid stations, or want sodium separate from carbohydrate | Easy to overdo; useless without water; some runners find swallowing capsules while running hard |
| High-sodium drink mix | Salty sweaters in heat; carrying your own bottle; combining fluid and sodium in one step | Ties sodium intake to fluid intake; limited by how much you carry |
| Standard sports drink | Races under 3 hours in mild weather; sodium arrives with carbohydrate and fluid | Usually only 200 to 500 mg per litre, too little for salty sweaters or heat |
| Salty gels and chews | Topping up during marathons without extra products | Sodium content is unpredictable between brands; rarely enough on its own |
| Salty real food | Ultras and long training runs; breaks the sweetness fatigue | Slow to eat, needs water, hard to dose accurately |
Half marathon
Cool conditionsSalted breakfast; sports drink on course; no tablets
Hot conditionsSalted breakfast plus 500 mg pre-load; one capsule at the hour mark for salty sweaters
Marathon
Cool conditionsGels with sodium plus course sports drink, about 300 to 500 mg/h; salty sweaters add one capsule per hour
Hot conditions500 mg pre-load; 1 to 3 capsules per hour or a high-sodium mix in a carried bottle; drink to thirst
50K to 50 miles
Cool conditions500 to 700 mg/h, mixing capsules and salty food at aid stations
Hot conditions700 to 1,000 mg/h; alternate capsules and drink mix; reassess every 2 hours
100K and beyond
Cool conditions500 to 800 mg/h averaged; watch for salt cravings and puffy fingers as signals
Hot conditionsSame, with the top of the range through the hottest hours and a dedicated bottle for sodium
| Race | Cool conditions | Hot conditions |
|---|---|---|
| Half marathon | Salted breakfast; sports drink on course; no tablets | Salted breakfast plus 500 mg pre-load; one capsule at the hour mark for salty sweaters |
| Marathon | Gels with sodium plus course sports drink, about 300 to 500 mg/h; salty sweaters add one capsule per hour | 500 mg pre-load; 1 to 3 capsules per hour or a high-sodium mix in a carried bottle; drink to thirst |
| 50K to 50 miles | 500 to 700 mg/h, mixing capsules and salty food at aid stations | 700 to 1,000 mg/h; alternate capsules and drink mix; reassess every 2 hours |
| 100K and beyond | 500 to 800 mg/h averaged; watch for salt cravings and puffy fingers as signals | Same, with the top of the range through the hottest hours and a dedicated bottle for sodium |
Only some. If you run for more than about 2 hours, particularly in heat, and you sweat heavily or lose a lot of salt, tablets are a convenient way to replace 300 to 800 mg of sodium per hour. Runners doing events under 90 minutes, or easy runs in cool conditions, get all the sodium they need from food and do not benefit.
Most capsules contain 200 to 250 mg of sodium. Average sweaters in warm weather need one to two per hour; salty sweaters in heat need three to four or should switch to a high-sodium drink mix. Subtract the sodium already in your gels and drink, and take every capsule with 150 to 250 ml of water. If you have high blood pressure, or a heart or kidney condition, talk to a doctor before using salt tablets.
Not reliably. Studies of cramping runners have not found lower blood sodium than in runners who did not cramp, and the strongest predictor of cramping is fatigue from running harder or longer than you trained for. Salt may help a minority with very high sweat losses, but pacing and conditioning matter far more.
Sweat rate multiplied by sweat sodium concentration. A typical runner sweating 1 litre per hour at 1,000 mg per litre loses about 1,000 mg an hour; a salty sweater in heat can lose 2,000 to 3,000 mg. Replace roughly a third to two thirds of that during runs longer than 2 hours.
A salted breakfast 3 hours before covers cool conditions. For a hot marathon, add about 500 mg of sodium with 500 ml of fluid around 90 minutes before the start. Do not swallow several capsules on the start line; that just causes nausea in the first 5K.
Yes. Above roughly 1,000 to 1,200 mg per hour in capsule form, most runners get nauseous and bloated, and taking capsules without water pulls fluid into the gut. Sodium overload is rare because the kidneys handle it, but the stomach sets the limit long before then.
For runs under 90 minutes, none beyond a salted meal before. For runs over 2 hours in cool weather, most runners do well on 300 to 500 mg per hour. In heat, or for anything over 4 hours, aim for about 500 to 800 mg per hour, because a higher sweat rate means more sodium lost each hour. Salty sweaters in heat may need 800 to 1,200 mg. Count the sodium in your gels and drink first, then make up the rest with tablets.
Maybe, but check your drinking first. Headache and nausea are also early signs of low blood sodium from drinking more than you sweat, and extra salt does not fix that. If you drank a lot of plain water, weighed more after the run than before, or have puffy fingers, drink less next time. If you drank to thirst and finished with white salt marks on your kit, try adding sodium on your next long run. Confusion or vomiting after a long event needs medical help, not a salt tablet.
General guidance for healthy adults, not medical advice. Talk to a doctor or registered dietitian if you have a health condition, take medicines or have special dietary needs.
Mavr turns your sweat test into a sodium target for each run and race and tells you how to hit it with the tablets, drinks, and gels you already carry.
Ask Kai, the coach in the app