How Much Sodium Do You Need When You Train?
Sodium isn't the enemy. Unplanned sodium is.
Sodium helps your body hold fluid, send nerve signals and contract muscles. You need it to train well.
The problem isn't sodium itself. It's not knowing how much you're getting. Some days are full of takeaway and sauces. Other days, after a big sweaty session, you may be short.
What the national guideline says
Australia's Suggested Dietary Target for sodium is 2,000 mg a day for the generally well adult population. It's set to lower the long-term risk of chronic disease, especially high blood pressure.
That target is for the general population. It doesn't account for people who lose large amounts of sodium in sweat. The national review notes that sodium is lost through sweat, but it doesn't give guidance for athletes.
How much sodium you lose in sweat
This is where most people underestimate.
- In one large study of athletes, sweat held on average about 830 mg of sodium per litre, ranging from about 420 to 1,630 mg per litre.
- The same athletes sweated on average 1.2 litres an hour, but some sweated as little as 0.3 litres and others more than 5 litres an hour.
A larger study of 1,303 athletes found average sodium losses of roughly:
| Sport | Sweat rate (L/hour) | Sodium lost (mg/hour) |
|---|---|---|
| American football | 1.5 | about 1,290 |
| Endurance | 1.3 | about 1,190 |
| Soccer | 0.9 | about 800 |
| Basketball | 1.0 | about 790 |
Those are averages. Two people doing the same session can lose very different amounts. A "salty sweater" can lose twice as much as the person next to them.
Example: a one-hour gym session where you sweat 1 litre costs about 830 mg of sodium on average, and anywhere from about 420 to 1,630 mg depending on you.
Our coaching ranges
These are INFINITY-Coach coaching ranges for healthy adults who train and sweat regularly. They are not a medical prescription.
| Who | Daily sodium range |
|---|---|
| Women who train | 2,000 to 3,500 mg |
| Men who train | 3,000 to 4,500 mg |
| Rule of thumb | 30 to 50 mg per kg of body weight |
What that looks like by body weight:
| Body weight | 30 mg/kg | 50 mg/kg |
|---|---|---|
| 60 kg | 1,800 mg | 3,000 mg |
| 80 kg | 2,400 mg | 4,000 mg |
| 100 kg | 3,000 mg | 5,000 mg |
Stay towards the lower end on rest days, in cool weather, or if you sweat lightly. Move towards the higher end on long, hot or very sweaty training days.
How to work out if you're a heavy sweater
- Weigh yourself before training, in minimal clothing.
- Train as normal, and note how much you drink.
- Weigh yourself again straight after.
- Every 1 kg lost is about 1 litre of sweat (add whatever you drank during the session).
If you regularly lose 1 litre or more per hour, see white salt marks on your clothes, or get crampy in long sessions, you may need more sodium on training days.
Electrolyte drinks: when they help
The Australian Institute of Sport says electrolyte replacement may help people with high sweat rates, long sessions or salty sweat. For general training, it suggests about 500 to 700 mg of sodium per litre of fluid.
For most one-hour gym sessions, a normal meal afterwards replaces what you lost. Electrolytes matter more for long, hot or very sweaty sessions.
One warning: the main cause of dangerously low blood sodium in sport is drinking far more than you sweat. Adding salt doesn't prevent it. Drink to replace what you lose, not as much as you can.
How INFINITY-Coach tracks your sodium
Every meal you log updates your sodium for the day, along with potassium, calories, protein, carbs and fat. Log by voice, photo or text, or scan the barcode on packaged foods.
That means you can see, before the day is over, whether you're short after a big training day or well over after a takeaway dinner.
Who should be careful
Don't increase your sodium without talking to your doctor if you have high blood pressure, kidney disease or heart failure, if you're on a salt- or fluid-restricted plan, or if you take medication that affects sodium or fluid balance. This article is general information, not medical advice.
The answer
If you train and sweat, you probably need more sodium than a sedentary person. But you don't need a guess. Weigh before and after training, know your range, and track it.
References
- National Health and Medical Research Council. Australian and New Zealand Nutrient Reference Values for Sodium. 2017. https://www.eatforhealth.gov.au/sites/default/files/2022-10/2017_ANZ_NRVs_for_Sodium_%28containing_recommendations%29.pdf
- Baker LB, Barnes KA, Anderson ML, Passe DH, Stofan JR. Normative data for regional sweat sodium concentration and whole-body sweating rate in athletes. Journal of Sports Sciences. 2016;34(4):358–368. https://pubmed.ncbi.nlm.nih.gov/26070030/
- Barnes KA, Anderson ML, Stofan JR, 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;37:2356–2366. https://www.gssiweb.org/sports-science-exchange/article/normative-data-for-sweating-rate-sweat-sodium-concentration-and-sweat-sodium-loss-in-athletes-an-update-and-analysis-by-sport
- Australian Institute of Sport. Sports Supplement Framework: Electrolyte Replacement Supplements. Updated March 2021. https://www.ais.gov.au/__data/assets/pdf_file/0020/1000487/36194_Sport-supplement-fact-sheets-electrolytes-v5.pdf
Sodium figures were converted from mmol to mg (1 mmol of sodium = 23 mg) and rounded.