Any process that activates or increases the activity of a sodium:hydrogen antiporter, which catalyzes the reaction: Na+(out) + H+(in) = Na+(in) + H+(out).
Synonyms:
exact_synonym:
positive regulation of sodium:hydrogen antiporter activity; up regulation of sodium:hydrogen antiporter activity; upregulation of sodium:hydrogen antiporter activity
narrow_synonym:
activation of sodium:hydrogen antiporter activity; stimulation of sodium:hydrogen antiporter activity