You Can't Out-Train Poor Hydration: Expert Tips to Unlock Your Best Marathon Yet

With marathon season fast approaching and thousands of runners preparing for events like the London Marathon, endurance performance expert Dr Priya Gopaldas reveals why hydration isn’t just about water – it’s also about replenishing the electrolytes your body needs to train stronger and recover faster.

photo of woman listening to music on earphones jogging down a paved street — Hydration tips for marathon training (Andrea Piacquadio on Pexels.com)

“Many runners focus on mileage and pace, yet ignoring hydration strategy can undo weeks of training,” says Dr Gopaldas. “Even mild electrolyte imbalance can lead to early fatigue, muscle cramps, and hindered recovery – issues easy to avoid with the right approach.” Electrolytes – not just water – are essential for marathon training because they regulate fluid balance, muscle contraction and nerve signalling, all of which are crucial during long training runs and race day itself.

Top Hydration Tactics for Marathon Training

Start Every Run Hydrated
Hydration begins before you lace up your trainers. Runners should prioritise fluid intake throughout the day, not just immediately before a long session. Drinking plain water is important, but pairing it with electrolytes helps your body retain and use fluids more effectively.

Use Electrolytes for Longer Runs
On training runs over 60 minutes, electrolytes like sodium, potassium and magnesium are lost in sweat and must be replaced to sustain performance. Instead of water alone, consider a tailored electrolyte solution that supports mineral balance.

Sip During and After Workouts
Instead of big gulps only at the end of a run, take small, regular sips – particularly on long efforts or in warm weather. Follow up your workout with a hydration drink that helps restore your body’s electrolyte levels and kick-starts recovery.

Know the Signs of Electrolyte Imbalance

Fatigue, muscle cramps, dizziness or nausea during training are often mistaken for “just tired legs” – but they can be signs of electrolyte depletion. Addressing these early can keep you training steadily and safely.

Dr Priya Gopaldas is nutrition ambassador for O.R.S Hydration.

Emily Cleary

After almost a decade chasing ambulances, and celebrities, for Fleet Street's finest, Emily has taken it down a gear and settled for a (slightly!) slower pace of life in the suburbs. With a love of cheese and fine wine, Emily is more likely to be found chasing her toddlers round Kew Gardens than sipping champagne at a showbiz launch nowadays, or grabbing an hour out of her hectic freelancer's life to chill out in a spa while hubby holds the babies. If only!