Why Every Runner Should Think About Fuelling Properly This Winter

I’d imagine most of you reading this will know most of this already. The thought of winter training can be daunting, bleak even. Dark mornings and evenings; the weather is atrocious, or unpredictable at best. But if you can drown out the noise of your own subconscious and actually head outside, winter training is where most of the real gains can happen.

Quiet miles. Early mornings. Sessions that feel harder than they should. And recently I realised that I wasn’t fuelling the same, but I’ve actually no idea why. So it got me thinking, is it just me? So, I thought it wise to have a look at winter fuelling specifically.

Just: Do I have enough energy, hydration, and electrolytes to train well today?

So after a fair bit of digging, here is why winter makes that question more important.

1. Cold weather increases energy demand.

When the temperature drops, your body works harder to maintain core temperature, even during exercise. Although your body feels like it’s ‘warmed up’, it’s actually still just above freezing!

That means:

• You burn more calories than you realise
• Perceived effort can feel higher at the same pace
• Energy dips hit faster when under-fuelled

This being said, it doesn’t mean you need to start carb-loading for a 5k around the block in the cold.

But once you get past the hour or 90-minute mark, especially during steady or tempo running, you will benefit from a small, steady carbohydrate intake.

Real-world example:

I’m currently doing long runs on Sundays. I’ve found that if they’re 75–90 mins+, they’re noticeably smoother with some form of steady carbs throughout.

2. Hydration quietly drops, even though you sweat less.

Winter dehydration is sneaky.

You lose fluid through:

• Breathing in cold, dry air
• Sweat that evaporates quickly
• Dressing warmer than you need

People feel less thirsty in winter, so they drink later than they should.

The result:

Heavier legs and slower recovery, and sessions that feel harder than they ought to.

Real-world example:

If you’re running for an hour or more, or cycling for more than 90 minutes, carrying some hydration (even just electrolytes in water) makes a big difference.

3. Gut training is easier in winter

If you’re building toward a spring race, your long runs now are the time to teach your stomach how to handle fuel.

This is called gut training in sports science.

It simply means consistently practising:

• Small amounts of carbohydrates
• Fluids
• Electrolytes

So your stomach is comfortable handling them on race day.

Do this now, and you prevent GI issues later. The current Leadville 100 record holder, David Roche swears by this technique (only on a much grander scale!).

4. Good fuelling helps you finish strong, not just grind through

When cycling long in the winter, and the same goes for running, but that last 20–30 minutes can feel a bit grim.

Cold extremities, plus lower glycogen, can get you to bonk before you know it. If you fuel more consistently, it can not only change that picture but also make your efforts more enjoyable and mean there is one less thing to worry about.

For me, at least, it also makes it more likely that I will get out and train again tomorrow, even if it’s just a slow zone-two plod or a strength workout.

Really, winter is all about showing up consistently. Fuel helps with that consistency.

Some Simple Winter Fuelling Guidelines

For runs under 60 minutes

• Water is fine.
• Maybe some electrolytes if it’s very cold, dry or windy. Or if your spending a lot of time in centrally heated places.

60–90 minutes

• A small amount of carbohydrate can help (20–30g per hour).
• Hydration becomes more important, even if you don’t feel thirsty.

90 minutes to 2 hours+

• 30–60g carbs per hour
• Fluids + electrolytes
• Regular sip-feeding, not “big gulps”

Cycling (because effort is lower, duration is longer)

• Anything over 90 minutes generally benefits from steady fuelling
• In the cold, hydration matters just as much as in summer, the air and extra layers dry you out fast
  

References:

Cold weather metabolic demand

Graham et al (2008)
https://journals.lww.com/acsm-msse/fulltext/2008/05000/metabolic_adjustments_to_cold_exposure.6.aspx
Castellani & Young (2016)
https://pubmed.ncbi.nlm.nih.gov/26960438/

Hydration in cold conditions

Kenefick (2018)
https://pubmed.ncbi.nlm.nih.gov/30324579/
Cheuvront & Sawka (2011)
https://pubmed.ncbi.nlm.nih.gov/21424972/

Gut training & carb absorption

Jeukendrup (2017)
https://pubmed.ncbi.nlm.nih.gov/28455707/
IOC Consensus Statement (2018)
https://pubmed.ncbi.nlm.nih.gov/29540365/