REF-220 · McCubbin AJ et al., 2025 · Journal of the International Society of Sports Nutrition, · Paper
Sodium Intake for Athletes Before, During and After Exercise: Review and Recommendations
Key Findings
Athletes in sports with large body-water turnover (team, endurance, racquet sports) commonly focus on sodium-containing foods, drinks and supplements before, during and after exercise; current guidelines for these scenarios are non-specific because evidence was lacking when they were written.
There is no evidence that athletes need more dietary sodium from day to day, because the kidneys and sweat glands keep sodium losses in check.
Whether before, during or after exercise, what shapes health and performance is how sodium and water relate to each other, rather than sodium balance or total body sodium viewed alone. Via its effect on extracellular osmolality, that sodium–water relationship governs thirst, fluid retention (overall body-water balance) and how fluid splits between the intracellular and extracellular compartments.
Sodium recommendations therefore have to be set against BOTH how sodium losses change AND how fluid balance changes (fluid losses and intake), instead of being planned from sodium losses alone — the traditional approach of many athletes, coaches and practitioners.
The common problems (gastrointestinal issues, exercise-associated hyponatraemia) generally arise from a mismatch between sodium and fluid balance.
Open questions named by the author: the form of sodium (chloride vs citrate), the delivery method (solution, food, capsules), and whether oral sensing of salty taste has a role.
Practical Application
Review conclusion: there is no evidence athletes need more dietary sodium day to day, and sodium intake around exercise should be planned against fluid balance — how much is drunk and lost — not against sweat sodium losses alone; GI problems and exercise-associated hyponatraemia come from a sodium-water mismatch. For the athlete: decide the fluid plan first, then fit sodium to it; a sodium target without a fluid plan is the traditional mistake the review argues against.
The author flags that some recommendations rest on limited evidence, extrapolation to specific scenarios or theoretical modelling, and that findings need reproducing across age, sex and ability and in weight-bearing or intermittent exercise — quote the principles, not precise thresholds, from this entry.
Limitations
Narrative review; the author states that some recommendations are based on limited evidence, extrapolations and theoretical modelling.
Evidence base skewed toward a narrow range of athletes; reproduction across age, sex, ability and exercise types is called for by the author.
A narrative review, not a systematic one; the recommendations are the authors’ interpretation of the evidence.
Sweat sodium varies widely between individuals, and the ultra-endurance recommendations rest on limited data.
How this entry was checked and changed
Why this level
regraded 2026-09-27 from A-: narrative review by a leading sodium/hydration researcher, no systematic method; the author states some recommendations rest on limited evidence, extrapolation and modelling
Content correction 2026-09-27
"Ultra-endurance >4 h, sweat sodium >40 mmol/L, sweat rate >1.5 L/h, replacing >90% of fluid losses -> consider testing; events <4 h taste guides intake; >4 h in heat consider a sweat patch" -> none of these thresholds are in the abstract; removed and pointed to REF-223 / REF-221 as "Not from this paper".
"Weight-sensitive cyclists" line and Sport "cycling" -> the review covers team, endurance and racquet sports; Sport set to general.
Added the abstract's mechanism (sodium-water relationship via extracellular osmolality), the GI/hyponatraemia statement and the author's own evidence caveats; Level A- -> B+ (narrative review) per KB-LEVEL-RUBRIC.