24-Hour Marathon Prep: What You Must Do Before Race Day

Preparing for a marathon doesn’t just begin on race morning—it starts the day before. Whether you’re approaching your first marathon or adding another finish to your belt, nailing the final 24 hours is crucial. In this guide, pulled from direct experience and 1,791 consecutive running days, I’m sharing the most effective strategies for prepping your body and mind for marathon success.

1. No Running the Day Before

It sounds simple, but many runners make this rookie error. The best advice? Don’t run or do any strenuous exercise on the day before your marathon. Although I personally kept up my running streak with a light 5km jog at a slower pace (for charity fundraising reasons), resting your legs is key. Most marathon training plans include a tapering period, with some runners not running at all the day before. Give your legs the best chance to feel fresh on race morning.

2. Carb Loading: Fuel Up the Right Way

The day before your race should be the climax of a carb-loading phase, ideally starting 48–72 hours prior. Aim for 8-10g of carbohydrates per kilo of body weight in the 24 hours before race day. For a 66.5kg runner like myself, that’s about 665g carbs—a staggering target, especially for heavier runners. The trick is to spread it out, choosing starchy, easily digestible foods such as pasta, rice, potatoes, and bread. Don’t overload on foods that might upset your digestion; research and try foods during training runs to see what works for you.

3. Rest and Recover

Spend as much of the day off your feet as possible—legs up, on the sofa, and relaxing. This helps minimise fatigue and gives your muscles time to recover before the big effort.

4. Stay Hydrated (and Mind Your Electrolytes)

Hydration is more than just water. Start sipping on electrolyte drinks or tablets the day before your race to ensure your sodium, potassium, and fluid levels are balanced. This helps stave off cramps and keeps your muscles working efficiently.

5. Race Morning Nutrition

Your marathon morning starts early. Have a solid, familiar breakfast at least 3 hours before the gun—something like porridge with honey and banana, paired with hydration fluids. From there, continue to top up every 30 minutes with around 30g of carbs, using bananas, energy bars, drinks, or gels. In my regimen, I take a gel half an hour before the race and another at the start—preferably with caffeine for an extra boost.

6. Don’t Try Anything New

The cardinal rule: Do not introduce new foods, drinks, or gels on race day. Everything you consume should have been tested in training. Digestive distress can end a race faster than tired legs.

7. The Power of Planning

It can’t be overstated: plan every detail, from resting times to carb intake. Use tech (AI or online calculators) to craft your nutrition plan, and don’t stress if you don’t hit your carb target exactly. Consuming more than usual will still give you an edge.

The meticulous planning in the 24 hours before your marathon is what sets you up for success. Take hydration, carb loading, and rest seriously, and never underestimate the power of experience and a well-laid plan. Good luck on race day—you’ve earned it!

Found this helpful?
Share, comment, and subscribe to support our fundraiser and help save children’s lives through the Runpreneur challenge.