Do electrolyte drinks actually matter?

They can, and the label is how you tell a real one from flavored water. Electrolytes — mainly sodium, plus potassium and magnesium — are lost in sweat, and replacing them matters most with heavy activity, heat, or when overall food intake is low and you are getting less sodium from meals. The catch is that mixes vary enormously: some carry a gram of sodium per serving, others a token amount in a sugary base. Read the electrolyte panel and the sugar line, not the color. And if you manage blood pressure or a kidney or heart condition, your sodium and potassium targets are a clinician conversation, not a drink mix's call.