Some people do run a half marathon without proper training, yes. People talk about it on Reddit. They’ll have a break from running for a while, want to get back into it because they miss it, and then within days or weeks, do a half marathon. I’ve never done that, but they say it hurts – and I’d imagine it does!
The BBC told us back in 2012:
John Brewer, professor of sports science at the University of Bedfordshire, agrees it is physically possible as long as the competitor has some experience of running and attempts it at the lowest possible intensity.
Seriously, half marathon, no training?
As a runner, I don’t recommend it. It’s testing enough with the training, and 13.1 miles on no training out of nowhere is a big ask. A medical study in 2000 looks into why. It basically means that the longer of a break you take from running, the more of an impact it has on you, in two ways.
First, it affects your cardiovascular levels and your VO2 max (which is how fast your heart, lungs and muscles can keep up with you doing intense exercise). Secondly, it impacts your muscles, and how well your brain connects to your muscles.
It sounds very ‘science’, but it’s true. If you’ve not run for weeks, you’re going to struggle to keep up. And your muscles will really, really hurt the next day.
Of course, you can train properly.. How long does it take to run a half marathon? Your averages are over here.
How to run a half marathon without training
If you were crazy enough to do that, this is how I’d go about it.
What to wear running a half marathon
I’d go with comfort and security. It’s got to last you 13.1 miles running (and maybe some walking if you’ve not done any practice!). So I’d wear comfy leggings, a sports bra, running trainers, and cushioned socks.
What I’d eat before a half marathon
Again, I would have gotten myself into a routine so I know what I can run on and how much energy I’ll need for the race. But I’ve often eat a banana at least 30 minutes before a run. I sometimes struggle with digestion and this light breakfast gives me good enough energy in my experience (for a shorter run!). So maybe some brown or wholemeal toast with banana and peanut butter for the longer distance.
If you’ve got time I’d also take some energy gels in some form. My dad would shove haribos or sugary/tangy sweets in his pocket. Great for not taking up much space, and also a good energy burst.
What I’d drink before it
I’d hydrate properly the day before, so at least 2 litres of water. And then have a drink the morning of the half marathon. Then, when you’re mid race, take advantage of the water stations. There will usually be several throughout. Take one of the polystyrene cups of water, or sports drinks, whatever they offer. Sometimes you might think you don’t need it for a bit.
Trust me, from running 2 half marathons with training, use your water stations. Your body needs it.
What I’d listen to during the half marathon
I couldn’t run a race without listening to music. Some races won’t let you wear chunky headphones for safety reasons. But if you can, I’d listening to some great running music.
I can’t say what I learnt
I’ve never done it so I can’t tell you! But I imagine it would hurt, a lot.. You generally suffer with your legs when you have trained for a half marathon.
It depends on how much you’ve actually ever run
If you’ve never run at all, not even once, so you’re a total newbie, then I’d say you might seriously injure yourself if you run a half marathon without any training. If that’s you, I’d encourage you to learn how to start running as a beginner. Then consider getting a good 5k pace. Maybe a couch to 10K. Those are some good goals.
If you’ve dabbled and some experience running, you’ve done the milage historically, but you’ve not been truly committed recently, it’s less of a bad idea. Still, I’d like to always be prepared as much as possible… Why wouldn’t you?
My 3 top tips for half marathon training
When I decided to train for a half marathon after a 10K, I thought it would be just a case of ‘upping the miles’ and all would be fine. There I was, Googling marathon plans for first time marathon runners. Here’s my personal 3 tips on half marathon training.
-
Be realistic
I can’t emphasise this enough. Don’t, whatever you do, tell yourself you’ll just be able to up the miles and be done with it.
Yes you’re more than capable of running a marathon, but things WILL go wrong. Expect them. Don’t expect. Life will get in the way. The initial buzz will settle down and the realness that you have actually paid to participate will hit you. You will procrastinate. So here’s number two.
2. Create a plan to work with, and expect it to go a bit wrong
In the early days of ‘omg I’ve signed up for my first marathon’ excitement, I quite proudly produced my very own personalised Excel spreadsheet. But I went wrong a little. Two things are important here.
A) To make a plan. Create something. A note on your door to nudge you to train. A reminder on your phone to make the £40 worth it. An Excel spreadsheet.
B) To not panic if you wobble away from it, for whatever reason. What matters is that you create something to wobble from. You won’t move if you don’t have a goal. It’s always better to move slowly and painfully towards your goal than to not move at all.
3. Networking
This is just a really fancy way of saying get support. You’ll need it. But, let me clarify that that’s not me saying you’re weak. You’re training for a half marathon, so you’re strong. Respect. But you’re also human. Everyone needs support at some point. Some more than others in different ways, and that’s okay.
Tell Facebook. Screenshot a photograph from last year’s event onto your Instagram. Tweet it. Heck, blog about it. But don’t stop at social media. As incredible and supportive as social media can be for this exact purpose (#halfmarathontraining), your offline, actual friends and family will be your rock.
Nearer the time, sponsorship is a great way to motivate yourself and get support. It will be an encouraging reminder that you’re doing this for good reasons too.
Written by Katie McDonald, 21st November 2024, Updated 6th April 2025.
Instagram | Runkeeper | Facebook | X (Formerly Twitter) | LinkedIn | TikTok
