An integral part of hydration is electrolytes.
Electrolytes are essential minerals such as, sodium, potassium, calcium, magnesium, and chloride.
They ensure proper fluid balance in your body regulate muscle contraction and nerve impulses.
You get electrolytes from your food and drinks.
When it comes to exercise, adding an electrolyte drink to your regime could be beneficial, especially if you are engaging in long duration exercise for 90+ minutes or exercising in hot temperatures. This will help replenish what was lost through sweat.
For example, if you are going for a long bike ride or long run, it would be beneficial to consume electrolytes.
I personally drink them on hikes and runs regularly. I bring a hydration reservoir for water and then a collapsible reusable bottle for electrolytes.
My go-tos are Nuun Sport Hydration tabs. The watermelon and strawberry lemonade are my two current favorite flava flavs.
Nuun also has hydration options for immunity, recovery, energy, and rest.
Keep in mind that Nuun tabs are not for nutrition. What I mean by that is that they provide electrolytes, not calories (only ~15 calories/serving).
If you're looking for an option to refuel with carbs, I would suggest adding either a intra- or post-workout snack/meal or reaching for a drink that has both electrolytes and carbs (i.e., Powerade).