The issue of salt intake is controversial, often riddled with conflicting information. We have already covered these issues in the brief summary, and in this article we will discuss how different physical activities affect our salt intake and how we can optimize it.
Why is salt important for us?
Table salt contains mainly sodium chloride, which is essential for proper digestion, blood pressure regulation and the functioning of our organs. In addition to its role in water and fluid balance, sodium is vital for stimulating muscle and nerve cells, and controlling acid-base balance.
In addition, sodium helps maintain electrolyte concentrations of the serum responsible for protection against pathogens, increases thirst and reduces the amount of urine produced, which ultimately reduce physical fatigue and health problems resulting from imbalances in endurance sports. (1)
Most of us are aware of the importance of hydration, but what many people don't know is that in addition to water, we also need salt. The good news is that salt deficiency is not something most people need to worry about.
Nearly everyone consumes enough salt
Whereas salt used to be a precious and hard-to-get mineral, it is now available almost everywhere at a low price. It is added to ultra-processed foods for its flavour enhancing and preservative effects, but various cheeses, breads, salted peanuts and the like also contain a lot of salt, as do the average restaurant and even home-cooked meals. Natural foods contain some salt even without any additives, albeit these amounts are dwarfed by the added amounts.
The average diet is therefore high in salt, and although various health organisations recommend lower intakes, very few people take this into account. Interestingly, primitive peoples consumed much less salt than modern people today. (2) This, combined with their higher intake of potassium and regular physical activity, has contributed to their lower blood pressure and much lower incidence of cardiovascular disease.(3,4)
So, although salt is something that everyone needs, it is not a good idea to explicitly encourage its consumption - but in some select cases it may be beneficial.
An exception might be health-conscious people whose diet consists mainly of minimally processed natural foods, and who do not eat bread or dairy products. In their case, if they do not add enough salt to their food, they may even have too low an intake of sodium, especially if they exercise regularly. Exercise can significantly increase our need for salt, especially endurance exercise in a hot and humid environment with a lot of sweating. People who work in similar environments may also need more salt.
The relationship between salt and training
Depending on the type of exercise you do, your blood sodium levels can drop quite a bit, which can cause a variety of problems.
Also known as water intoxication, hyponatraemia literally means low sodium levels in the blood. A variation of this is exercise-associated hyponatraemia (ETH), which is usually caused by excessive water consumption and/or salt loss from too much sweating. (5)
It is also very important to know about it because in severe cases it can lead to seizures, coma and ultimately death. Even much milder hyponatraemia causes many problems, such as impaired physical performance and increased fatigue, as well as muscle cramps, headaches and nausea.(6)
In order to prevent hyponatraemia during exercise, it is important to watch your salt intake as well as your fluid intake. This is not an easy task, as there can be huge variations in need from person to person.
Who is affected by excercise-related hypanatraemia?
Fortunately, the majority of people do not need to worry about developing hyponatraemia because, as mentioned earlier, almost everyone consumes plenty of salt and few people do any type of exercise that would involve significant salt loss.
With weight training, resistance training, shorter runs and bike rides, martial arts training and swimming we rarely lose enough salt to warrant replacement, unless one has already significantly restricted salt intake.
Exercises for which adequate salt supplementation may be important are endurance exercises lasting several hours, especially when performed in a warm or humid environment. (7) Examples include marathons, triathlons and long-distance cycling.
ETH often occurs in these races and to avoid it, it is important to avoid excessive hydration in the form of water or other hypotonic drinks. (8) In addition, it is important to ensure adequate salt intake around training sessions and to be conscious of the intensity of the training and the environmental conditions.
How to prevent low sodium levels?
Salt loss from sweating is difficult to determine, as the sodium content and amount of sweat can vary considerably among athletes. (9) It is therefore very important to monitor symptoms, particularly nausea and nervous system problems during competitions, and to work out over time roughly how much extra salt you need.
A good solution may be to increase the salt content of traditional meals, have a few salty snacks with your fluids, or use sports drinks that contain up to 300-700 mg of sodium per litre. (1) However, high temperatures and humidity, and individual needs may mean that you need much more sodium.
The relationship between salt and performance
Adequate hydration is essential for sports performance, and salt is an essential element for this. A weight loss of just 2% due to dehydration compromises cardiovascular function and reduces oxygen and glucose delivery to muscle cells, which can lead to a significant performance deficit. (6)
A randomized trial tested the effects of salt supplementation in experienced athletes during a triathlon competition. Participants in one group were supplemented with salt both before and during the race, while participants in the other group were not. As expected, salt supplementation resulted in athletes losing less water, having higher sodium and chloride levels in their blood after the race and finishing faster than their similarly capable but non-salt supplemented counterparts. (10)
Salt plays an important role in hydration and can improve sports performance. In particular, for endurance sports over long periods of time, it is important to supplement sodium as well as fluids, as a lack of sodium can impair physical performance and even cause severe symptoms.
Bicarbonate of soda, which also contains sodium, has also been shown to improve sports performance when consumed in large quantities. Although it is not yet known exactly what makes it so effective, it probably inhibits the acidification that occurs during intense exercise due to its alkaline chemistry. This has the effect of delaying fatigue and the resulting loss of performance.
- Valentine V. The importance of salt in the athlete's diet. Curr Sports Med Rep. 2007 Jul;6(4):237-40. PMID: 17617999.
- Eaton SB, Konner M. Paleolithic nutrition. A consideration of its nature and current implications. N Engl J Med. 1985 Jan 31;312(5):283-9. doi: 10.1056/NEJM198501313120505. PMID: 2981409.
- Raichlen DA, Pontzer H, Harris JA, Mabulla AZ, Marlowe FW, Josh Snodgrass J, Eick G, Colette Berbesque J, Sancilio A, Wood BM. Physical activity patterns and biomarkers of cardiovascular disease risk in hunter-gatherers. Am J Hum Biol. 2017 Mar;29(2). doi: 10.1002/ajhb.22919. Epub 2016 Oct 9. PMID: 27723159.
- Lemogoum D, Ngatchou W, Bika Lele C, Okalla C, Leeman M, Degaute JP, van de Borne P. Association of urinary sodium excretion with blood pressure and risk factors associated with hypertension among Cameroonian pygmies and bantus: a cross-sectional study. BMC Cardiovasc Disord. 2018 Mar 7;18(1):49. doi: 10.1186/s12872-018-0787-3. PMID: 29514623; PMCID: PMC5842583.
- McGreal K, Budhiraja P, Jain N, Yu AS. Current Challenges in the Evaluation and Management of Hyponatremia. Kidney Dis (Basel). 2016 Jun;2(2):56-63. doi: 10.1159/000446267. Epub 2016 May 14. PMID: 27536693; PMCID: PMC4947691.
- Cheuvront SN, Carter R 3rd, Sawka MN. Fluid balance and endurance exercise performance. Curr Sports Med Rep. 2003 Aug;2(4):202-8. doi: 10.1249/00149619-200308000-00006. PMID: 12834575.
- Baker LB, Ungaro CT, Barnes KA, Nuccio RP, Reimel AJ, Stofan JR. Validity and reliability of a field technique for sweat Na+ and K+ analysis during exercise in a hot-humid environment. Physiol Rep. 2014 May 2;2(5):e12007. doi: 10.14814/phy2.12007. PMID: 24793982; PMCID: PMC4098735.
- Hew-Butler T, Loi V, Pani A, Rosner MH. Exercise-Associated Hyponatremia: 2017 Update. Front Med (Lausanne). 2017 Mar 3;4:21. doi: 10.3389/fmed.2017.00021. PMID: 28316971; PMCID: PMC5334560.
- American College of Sports Medicine; Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc. 2007 Feb;39(2):377-90. doi: 10.1249/mss.0b013e31802ca597. PMID: 17277604.
- Del Coso J, González-Millán C, Salinero JJ, Abián-Vicén J, Areces F, Lledó M, Lara B, Gallo-Salazar C, Ruiz-Vicente D. Effects of oral salt supplementation on physical performance during a half-ironman: A randomized controlled trial. Scand J Med Sci Sports. 2016 Feb;26(2):156-64. doi: 10.1111/sms.12427. Epub 2015 Feb 14. PMID: 25683094.
- Grgic J, Grgic I, Del Coso J, Schoenfeld BJ, Pedisic Z. Effects of sodium bicarbonate supplementation on exercise performance: an umbrella review. J Int Soc Sports Nutr. 2021 Nov 18;18(1):71. doi: 10.1186/s12970-021-00469-7. PMID: 34794476; PMCID: PMC8600864.