Summer Running Hydration Guide

Warmer mornings and long light evenings make summer one of the best times of year to run — but the heat quietly changes the rules. You sweat more, you lose salt faster, and the run that felt easy in April can leave you flat and foggy in July. The good news is that staying on top of hydration isn’t complicated. Get a few habits and a bit of kit right, and you’ll run stronger all summer.

Here’s how to do it properly.

Why summer hydration is different

When it’s hot, your body works harder to keep cool. You sweat more to shed heat, and that sweat isn’t just water — it carries electrolytes, chiefly sodium. Lose enough fluid and salt and you’ll feel it: your heart rate creeps up, your pace slows for the same effort, your legs feel heavy, and your head goes cloudy.

A useful rule of thumb: if you finish a run noticeably lighter than you started, that’s fluid you need to replace. And if your kit is crusted with white salt marks after a hot session, you’re a salty sweater — you’ll benefit more than most from electrolytes rather than plain water.

The aim isn’t to drink as much as humanly possible. Over-drinking plain water on long, hot efforts can actually dilute your sodium levels and make you feel worse. The goal is to replace what you lose — water and salt — in roughly the amount you’re losing it.

Before, during and after

Before you run, start topped up rather than trying to catch up mid-run. A glass or two of water in the couple of hours beforehand is plenty for most sessions. On very hot days, an electrolyte drink beforehand helps you start with your salt levels in a good place.

During the run, anything under about 45 minutes usually needs nothing but a sensible start. Once you’re past the hour mark — or it’s genuinely hot — start sipping regularly rather than gulping at the end. Little and often is far kinder on your stomach.

After you run, rehydrate steadily over the next hour or two. Adding electrolytes to your recovery drink helps your body actually hold on to the fluid instead of passing it straight through.

Water vs electrolytes: what your summer runs actually need

For easy runs in the heat, an electrolyte drink does more than water alone — it replaces the sodium you’re sweating out and helps you absorb and retain fluid. A clean, no-nonsense option is the Veloforte Attivo and Vivo electrolyte powders, made from natural ingredients and easy on the stomach.

For longer or harder summer sessions — long runs, race efforts, anything over 90 minutes — you’ll want carbohydrate as well as electrolytes, so you’re fuelling and hydrating in one bottle. STYRKR’s MIX60 and MIX90 drink mixes and the Maurten Drink Mix range are both strong choices here, delivering serious carbs alongside fluid.

You’ll find the full range on our hydration and drink mix collection, plus energy gels and chews over in nutrition for the days you need fuel on board too.

The kit that makes hot-weather running easy

Carrying fluid comfortably is the difference between actually drinking on the run and telling yourself you’ll be fine (you won’t). A few options, depending on how far you go:

Soft flasks collapse as you drink, so there’s no sloshing and they pack down to nothing. The Montane Ultraflask 500ml is a brilliant, do-everything soft flask with a high-flow bite valve — ideal for tucking into a vest or belt.

Handhelds keep water within easy reach for shorter hot runs without anything strapped to your back. The Ronhill Softflask with Sleeve adds a comfortable hand strap and a small zip pocket for keys or a gel — simple and effective.

Hydration vests are the answer for long runs, trails and races where you need to carry more fluid plus your phone, layers and fuel. The Ronhill OTM Vest is a superbly minimal, second-skin fit that disappears once it’s on. Browse the full hydration vest range here.

Not sure which to go for? That’s exactly the kind of thing worth a quick chat in the shop — a vest that fits well is a joy, and one that doesn’t will drive you mad.

Five practical summer running tips

1. Run early or late. Beat the peak heat by heading out before 9am or after the sun drops. You’ll run faster and suffer less.
2. Ease into the heat. It takes a couple of weeks for your body to acclimatise. Don’t judge your fitness by your first sweltering run of the year.
3. Plan routes with water and shade. Loops past a tap or a shaded park stretch make long summer runs far more manageable.
4. Wear light, breathable kit and don’t forget a cap and sunglasses — staying cool is part of staying hydrated.
5. Watch for warning signs. Dizziness, chills, goosebumps or stopping sweating in the heat are reasons to stop, cool down and rehydrate — not to push on.

Get it right at the source

Hydration keeps you comfortable — but so do the right shoes. If your legs are labouring in the heat, part of it might be your footwear working against you. Our expert gait analysis in the Stamford store takes the guesswork out of it: it’s a £40 service, with £20 back as credit towards your shoes, so you leave in a pair that genuinely suits how you run. Book your gait analysis online here.

Not ready to book but want a steer? Try our Find My Shoe finder for a quick match, or better still — pop into the shop at 42 Broad Street, Stamford. We’ll help you sort hydration kit, fuel and footwear in one visit, so you’re set for a strong summer of running.

Stay cool, drink smart, and enjoy the miles.