While You Are Moving
For sessions under 60 minutes at moderate intensity, water alone is enough for most people. Drink 150 to 200 ml every 15 to 20 minutes when sweating. In hot NZ conditions, lean toward the upper range and seek shade when possible.
Longer efforts—half marathons, multi-hour hikes, or cycling sportives—may need carbohydrates and electrolytes. Commercial sports drinks work; so do water plus fruit and a handful of pretzels. Practice during training, not on event day, to learn what your stomach tolerates.