As summer swelters on, those on the front line of athletic care should be especially vigilant of hyponatremia when treating sick patients or advising healthy individuals. Recommend having a variety of fluids freely available and advise people - especially exercising athletes - to drink when thirsty and reduce activity, splash with water, and seek a shaded spot when hot. Before we promote blanket advice to "drink lots of fluid" and "stay well-hydrated", we should be mindful that fluid is a balance - especially during exercise.