Low sodium usually comes from drinking too much, not from losing salt
Reviewers of this literature point to drinking past thirst, and to a hormone telling the kidneys to hold water. A smaller group of athletes is genuinely salt-depleted.
What the study found
Low blood sodium in sport is a water problem, not a salt problem
Two things go wrong together. Reviewers of this literature name drinking past thirst alongside release of vasopressin, the hormone telling the kidneys to hold water, as the dominant causes. They also say a smaller group of athletes is genuinely salt-depleted, so water is not all of it.
The caveat · One author chaired the consensus
Both are narrative reviews with no stated search and no risk-of-bias grading, so which literature they cite is at the authors' discretion. The lead author of one chaired the consensus conferences on this condition, which makes the summary authoritative and not independent of the position it summarises. 'Conclusively identified' is their own confidence wording, not a graded rating.