Electrolytes and Hydration for Training: What UK Athletes Actually Nee – GymStack

Hydration is not just about drinking more water. When you sweat — especially in heated gyms, long runs, or double sessions — you lose sodium, potassium, and magnesium. Replace them intelligently and you recover faster; overdo sugary sports drinks and you mainly buy calories.

When do you need electrolytes?

Sessions under 45 minutes — water is usually enough if you eat balanced meals
60–90+ minutes — electrolytes help maintain performance and reduce cramp risk
Hot yoga, outdoor summer training, or two-a-days — prioritize sodium replacement
Low-carb or fasted training — you may lose more sodium; consider a light electrolyte drink

What to look for on the label

Sodium — the main sweat electrolyte; 200–500 mg per serving is typical for exercise products
Potassium & magnesium — support muscle function; often paired with sodium
Sugar — useful during long endurance efforts; optional for gym sessions under 90 minutes
Caffeine — some hydration products add stimulants; read labels if you already use pre-workout