Can You Run A Marathon Without Training?

The short answer is yes, probably. It would take a lot of mental fortitude and probably some dark moments but you will be able to get there.

There are some examples of those that have run a marathon without training in the past:

  • Evelina Sinkevičiūtėunintentionally completed a marathon with no training after her boyfriend injured his knee. Despite the lack of preparation, she managed to finish the race, highlighting the power of mental fortitude and the unexpected things the human body can achieve.  
  • Brooks Wheelan: The comedian ran a marathon on a bet with no training. While he successfully completed the race, he suffered a severe case of iliotibial band syndrome. 

Could you be the next wild story? Sure. But is it worth it? That’s another question entirely.

While there are always going to be examples of people doing these seemingly crazy things with some success there are always risks and caveats. While the short answer is yes, the longer answer is: It’s going to hurt, a lot.

A runner in pain walking down some stairs after completing a marathon.

What Happens If You Run a Marathon Without Training?

Marathons are no joke. Covering 26.2 miles on foot isn’t just a test of endurance—it’s a full-body stress test. And if you’re not prepared? Well, your body will let you know- like a screaming child.

Here’s what you’re up against:

Injury Risks

Your body is a well-oiled machine, but without proper preparation, a marathon can feel like throwing it into overdrive with no oil change.

  • Plantar fasciitis – The connective muslce tissue gets angry. Really angry
    • Inflammation of the muscle in the underside of your foot. I’ve suffered with this a few times and it’s so painful you can barely walk.
  • Runner’s knee – Knees weren’t built for sudden 26.2-mile adventures.
    • Without conditioned muscles around the knee to take all of the impact of running, your knee joint will take the brunt of it.
  • Shin splints – Your shin bones will feel like they’re on fire.
    • Shards that can splinter off of your bone due to repetitive impact. I’ve not suffered with this but I can’t imagine running with bones sticking out is going to be comfortable.
  • Achilles tendinitis – That tendon at the back of your foot? Yeah, it won’t be happy.
    • Inflammation of your Achilles will not allow you to use elastic energy to run. Every time your foot hits the ground and pushes off will be agony.
  • Stress fractures – Tiny cracks in your bones. Not fun.
    • Like runners knee, when your muscles are not strong enough and get tired, your bones and joints will start taking the brunt of the impact.
  • Muscle cramps and strains – Because your muscles weren’t ready for this.

And in extreme cases, there’s rhabdomyolysis, a condition where muscle tissue breaks down so aggressively that it floods your bloodstream with toxins, potentially damaging your kidneys. Yes, it’s as bad as it sounds.

The Dehydration & Energy Crisis

Running for hours burns through your body’s fuel reserves fast. Without proper hydration and nutrition:

  • Your blood sugar drops, making you feel weak and dizzy.
  • You risk hitting “the wall” hard—where your body quite literally runs out of energy.
  • Dehydration can lead to heat exhaustion, confusion, and even heatstroke if conditions are hot.

You need to make sure that you take on board fuel and hydration consistently when you are running a marathon, regardless of how much you have trained for it. Although you’re more likely to know this if you have trained and planned for your marathon!

To run a marathon without training you will need good nutrition like this man with a hydration pack.

The Mental Battle

Let’s not forget the psychological aspect. Running a marathon untrained isn’t just about physical suffering—it’s a mental war.

  • Pre-race anxiety – You’ll question your life choices at the start line.
    • Oh, you will probably do this if you have trained for it too!
  • Motivation struggles – When your body says stop, willpower is the only thing keeping you going.
    • Having trained, you will have been in this situation a few times during your plan, so are more experienced at pushing through.
  • Mental exhaustion – The whole thing will feel like an eternity.
    • When you train for a marathon you know that from mile 20 it will be a battle. If you are untrained, this will probably be from mile 10.

At some point, it will stop being a run and will become a survival test.

So… What’s the Minimum Training for a Marathon?

If you actually want to enjoy a marathon (or at least survive it in one piece), some level of preparation is key.

Having run and coached athletes to many marathons, I recommend 12-26 weeks of training depending on your base fitness to build endurance and strength while reducing injury risk. The essentials include:

  • Base Mileage – Consistent running to strengthen your aerobic system.
  • Long Runs – Meticulously planning an increase in your longest runs to prepare your legs for the distance.
  • Speed Work – Shorter, faster runs that improve efficiency- my favourite.
  • Strength Training – Because strong muscles = fewer injuries.
  • Pacing Strategy – Knowing your personal effort levels so you don’t burn out too soon.
  • Rest & Recovery – Letting your body adapt and repair is just as important as training itself.

Skipping all of this? You’re rolling the dice. Good Luck.

Coach Chris and Friend holding medals at the end of the London Marathon 2019.
This is how I felt at the end of a marathon after training for 6 months…

Can You Walk a Marathon?

Absolutely. Many marathons allow generous cut-off times, meaning walking the entire course is an option. But don’t be fooled—walking a marathon still requires preparation.

  • Choose a walker-friendly race – Some events cater specifically to walkers.
    • There are some that have cut off times that will not cater for walkers, the Chicago marathon has a 6 hour 30 minute cut off for example, which is going to be too fast for many walkers.
  • Train for endurance – Long walks build stamina just like long runs do.
  • Stay hydrated and fueled – Even at a walking pace, your body needs energy. Mainly fats, but some carbohydrates too.

Walking a marathon can be a fantastic experience—offering a chance to soak in the atmosphere, enjoy the challenge regardless of running ability, and avoid the brutal impact of running on joints and muscles.

Should You Attempt It?

Let’s be real: running a marathon without training is possible—but it’s not smart.

You’ll finish if you’re stubborn enough. But at what cost? Injuries, extreme fatigue, and a terrible race experience? Probably.

If you really want to take on a marathon, do yourself a favour and prepare. A good training plan will not only help you finish—it’ll help you enjoy the journey.

And if you’re unsure where to start? Working with a coach can help. At Efficient Endurance, we focus on getting athletes race-ready without wasting time on unnecessary miles. Because training smart beats training long every time. Check out our coaching here.

So… are you ready to run a marathon? The right way?

About Me

Chris Searle the head coach of efficient endurance

Hi, I’m Chris.

I’m a professional coach with 14 years of experience. My coaching approach is all about time efficiency. Every session is designed to get the most out of your available training time, helping you improve without unnecessary effort.

I focus on smart, effective training that maximises your progress in the shortest time possible.

You can read more about my coaching journey on the About page.

 

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