Can You Run a Marathon Without Training?

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Your friend just asked you to run a marathon, but you have never done anything of the sort. You don’t want to look like a wimp, so you half-heartedly agree to run the marathon with your friend.

Of course, you haven’t trained for a full marathon, and you haven’t ever done any sort of prolonged running.

Some people may think that running a marathon is a walk in the park, but the fact of the matter is that it requires a lot of strength, stamina, and endurance, even for a short marathon. So, can you run a marathon without training?  

How Long does it Take to Train for a Marathon?

Since we are talking about running a marathon without training for it, it’s therefore important to put things into context. Knowing how long a professional trains for a marathon will give you a good idea of why you may not be able to run a full marathon without that same training sessions.

For the greenest of beginners, even the simplest marathon training routines are going to last for a minimum of 4 months. For true beginners looking to run a full marathon, it can take 6 months of daily strength and endurance training to run a full 50k stretch.

Therefore, if it takes a truly dedicated person somewhere around half a year to get to a point of physical conditioning where it is possible to run a 50k marathon in a single go, it’s not very likely that you can run that same distance without having trained for it.

To be able to get to this point, it takes a serious mixture of various training methods, including both speed and endurance training, using methods like tempo running, interval running, hill climbing, and more.

Runners who engage in marathon running also need to be in peak condition in terms of muscle strength. You may think that runners only run, but weight and resistance training, as well as plyometric leg training are part of a pro runner’s routine.

Simply put, you might be able to make it through a half marathon without training, but even this is quite a tall order. If you haven’t trained, after the first 10 to 15 miles, your body will start to break down.

Practically, nobody in the history of mankind woke up one morning and thought it would be fun to run a full-length marathon that same day, and actually managed to do it; unless you are Superman, it just cannot be done.

What Happens When You Don’t Train?

If you still think that it is a good idea to try and run a marathon without training for it, you will be in for quite the surprise. Without any sort of prolonged training, your marathon is not going to go well. Here are some of the results you can expect from trying to attempt this Herculean feat of endurance.

Injuries are Likely

One of the biggest issues with running a marathon without training for it is that injuries become more likely to occur. It takes strong, flexible, and mobile muscles to run long distances, and of course, lots of energy.

If you run a marathon without any sort of training, you are much more likely to pull or strain a muscle, or cause similar injuries, even those which are bone and joint-related.

Moreover, the more tired you get while running, the more likely you are to make a mistake. It only takes a second of not concentrating to take a bad step and twist your ankle. Extreme fatigue can quickly lead to injuries.

Lactic Acid and the Burn

One of the most common things to happen to endurance runners who don’t actually have any endurance or stamina is that horrible burning sensation.

When your muscles get tired, they suffer from a buildup of lactic acid, which is the substance that causes that burning sensation; your muscles to stiffen and lock up, and eventually force you to stop altogether due to the pain.

Without adequate training, you’ll be feeling that burn within a few minutes of running. It takes anywhere from 3 to 7 hours to complete a marathon, something you won’t be able to do if your muscles start burning at the 10 minute mark.

Shortness of Breath

At the very least, without adequate training, what’s going to happen pretty quickly into that marathon is that you are going to run out of breath.

Without training, it’s only going to take you a few minutes to experience shortness of breath, something that doesn’t work out well when you have to run for hours.

Of course, if you can’t get enough oxygen into your system, nothing else is going to work properly. A lack of oxygen not only leads to heavy breathing, but it’s actually what causes the buildup of lactic acid.

Total Energy Crash

If you aren’t trained to run long distances, you are going to suffer from a severe energy crash. If you stop running when you start to feel really tired, this is not an issue. However, if you push yourself too hard, you fight through the lactic acid and the heavy breathing, eventually your body will just give out.

Runners without adequate training have been known to collapse on the track. Not only that, but your body will be depleted of so much energy that you will likely feel tired not just for a few minutes, but for days to come. Simply put, your body is not used to such an extreme amount of exercise and will literally give out on you.

Extreme Soreness

Tiredness aside, something else that will result from attempting to run a marathon without training is many days of extreme muscle soreness and fatigue.

Think of it this way; when you first start training for a marathon, even with a light training regimen, your muscles are going to be sore and tired for a day or two after each session.

However, if you try to run a full marathon your first time running, your muscles are going to be taxed to the point where they may take days or even weeks to fully recover. Run a 50k marathon without any prior experience, and you are likely to be in pain for weeks.

You’ll Get Sick of It

Another thing that may happen if you try to run a marathon without training for it, based on the other 5 effects we have just talked about, is that you will be put off from running altogether. In other words, you might end up feeling so horrible that you may never want to try running again, and of course, that would be a shame.


At the end of the day, while you are more than welcome to attempt running a marathon without prior training, it’s not recommended. Chances are almost 100% that you won’t be able to make it to the finish, and if you do manage to cross the finish line, you will feel the after effects for days or even potentially weeks to come.