Running A Marathon Without Training: ALL The Reasons It’s A Bad Idea

As a certified running coach, it is extremely concerning when I see TikToks and other social media trends such as “I ran a marathon with no training and you can too!“

For example, in 2021, the Wade twins, who have nearly 1 million TikTok followers, filmed themselves running a 3:30 hour marathon, noting that they are “running the London Marathon today with absolutely zero training.”

That’s quite a fast time, though their use of “zero training” is a little misleading. More concerning is the fact that the search for “running a marathon without training” has millions of views on TikTok.

Running a marathon on zero training is not safe and can put you at risk for injuries and other problems.

Finishing a marathon typically requires several months of training, and is generally not recommended for new runners until they have been running consistently for at least six months to a year.

In this guide to running a marathon without training, we will discuss the risks of running a marathon without training and the proper training timeline for completing your first marathon so that you have a positive race experience and can cross the finish line healthy and happy.

People running a marathon.

Can You Run a Marathon Without Training?

While it is technically possible for many healthy adults to finish a marathon without training, it is not safe or recommended. 

You may be able to walk a marathon or jog/walk a six or seven-hour marathon with zero training, but if you’re hoping to run a four-hour marathon and run the whole way, you are setting yourself up for a high risk of injury, muscle soreness, and disappointment, if not worse.

We do not endorse running a marathon without proper training.

What Are the Risks of Running a Marathon Without Training?

Even with proper training, running a full marathon puts a tremendous amount of physical stress on the body.

Although not common, there are potential risks of marathon training and racing, including the following:

People running a marathon.

#1: Increase The Risk Of Myocardial Fibrosis

Although quite rare, studies have found1Wilson, M., O’Hanlon, R., Prasad, S., Deighan, A., MacMillan, P., Oxborough, D., Godfrey, R., Smith, G., Maceira, A., Sharma, S., George, K., & Whyte, G. (2011). Diverse patterns of myocardial fibrosis in lifelong, veteran endurance athletes. Journal of Applied Physiology110(6), 1622–1626. https://doi.org/10.1152/japplphysiol.01280.2010 that marathon running may increase the risk of myocardial fibrosis.

One study2Marathons damage the hearts of less fit runners for up to three months, MRI data suggest. (n.d.). ScienceDaily. Retrieved February 16, 2024, from https://www.sciencedaily.com/releases/2010/10/101025005836.htm found that adverse changes may persist for up to three months in novice marathoners (such as those who run a marathon without training!), and a large review found3Day, S. M., & Thompson, P. D. (2010). Cardiac Risks Associated With Marathon Running. Sports Health: A Multidisciplinary Approach2(4), 301–306. https://doi.org/10.1177/1941738110373066 that marathon running is associated with a low risk of sudden cardiac death.

#2: Increase The Risk Of Running-Induced Injuries

A large review4Wirnitzer, K., Boldt, P., Wirnitzer, G., Leitzmann, C., Tanous, D., Motevalli, M., Rosemann, T., & Knechtle, B. (2022). Health status of recreational runners over 10-km up to ultra-marathon distance based on data of the NURMI Study Step 2. Scientific Reports12(1). https://doi.org/10.1038/s41598-022-13844-4 looked at all of the potential health implications of distance running, with races ranging from the 10k to ultra marathon.

Marathon running was associated with an increased risk of running-induced injuries, such as knee pain and stress fractures, with approximately half of the active runners reported having multiple running injuries per year.

People running a marathon.

#3: Can Put Stress On The Kidneys

There is some evidence to suggest that marathon running can stress the kidneys,5Atkins, W. C., Butts, C. L., Kelly, M. R., Troyanos, C., Laursen, R., Duckett, A., Emerson, D. M., Rosa‐Caldwell, M. E., & McDermott, B. P. (2022). Acute Kidney Injury Biomarkers and Hydration Outcomes at the Boston Marathon. Frontiers in Physiology12. https://doi.org/10.3389/fphys.2021.813554 even when hydration is optimal. Acute kidney injury risk is even higher if you suffer from dehydration on race day.

#4: Can Provoke Muscle Tissue And Cellular Damage

Some studies6Ryu, J. H., Paik, I. Y., Woo, J. H., Shin, K. O., Cho, S. Y., & Roh, H. T. (2016). Impact of different running distances on muscle and lymphocyte DNA damage in amateur marathon runners. Journal of Physical Therapy Science28(2), 450–455. https://doi.org/10.1589/jpts.28.450 have found that marathon running can cause damage to DNA and muscle tissue.7Lippi, G., Schena, F., Salvagno, G. L., Montagnana, M., Gelati, M., Tarperi, C., Banfi, G., & Guidi, G. C. (2008). Acute variation of biochemical markers of muscle damage following a 21‐km, half‐marathon run. Scandinavian Journal of Clinical and Laboratory Investigation68(7), 667–672. https://doi.org/10.1080/00365510802126844

A large review noted that marathon running can cause an increase in acute phase proteins, cortisol (stress hormone), liver proteins, red cell breakdown, skeletal muscle cell damage, and blood in the urine and a decrease in testosterone and bone mass.8Wirnitzer, K., Boldt, P., Wirnitzer, G., Leitzmann, C., Tanous, D., Motevalli, M., Rosemann, T., & Knechtle, B. (2022). Health status of recreational runners over 10-km up to ultra-marathon distance based on data of the NURMI Study Step 2. Scientific Reports12(1). https://doi.org/10.1038/s41598-022-13844-4

‌Even though these aforementioned health problems and running injuries can occur even when runners are not tackling longer distances for the first time, failing to prepare your body with months of training runs, cross-training, strength training, and building your fitness level can certainly increase the risks.

People running a marathon.

Why Do You Need to Train for a Marathon?

I was 22 years old when I ran my first marathon. I started running cross country and track in middle school around the age of 12, so this was about 10 years into my running career.

While it isn’t necessary to train for 10 years before you start running marathons, I was very young and competing for my high school and university, so this was my trajectory.

Almost all marathon races do not even allow participants to register unless they are at least 18 years old due to the physical toll that marathon training and running the full marathon distance takes on the body.

Before you have reached skeletal maturity, the high impact nature of running can more easily cause overuse injuries to your ligaments, tendons, muscles, and bones, increasing the risk of stress fractures, shin splints, tendinitis, etc.9NILSSON, J., & THORSTENSSON, A. (1989). Ground reaction forces at different speeds of human walking and running. Acta Physiologica Scandinavica136(2), 217–227. https://doi.org/10.1111/j.1748-1716.1989.tb08655.x

‌Now that I work as a certified running coach, I generally recommend that beginners (who are adults) train for at least 6 to 12 months before beginning an official marathon training plan.

Ideally, you should have a year of running under your belt, having run a half marathon race before you start training for your first marathon.

This gives your musculoskeletal system time to adapt to the high-impact nature of running, which can reduce the risk of injury. It is also important for beginners to learn how to pace themselves. 

Marathon pace is generally slower than shorter races such as a half marathon, 10K, or 5K.

People running a marathon.

However, the challenge is really learning how to predict your fitness level and the pace you can sustain for 26.2 miles without hitting the wall or crashing and burning before crossing the finish line because you started out too fast.

One of the purposes of long training runs when you are doing proper training for a marathon is to learn your pacing strategy and also to help trigger the cardiovascular adaptations, metabolic adaptations, and musculoskeletal adaptations your body needs for a full marathon race.

For example, the longest runs on a marathon training plan help strengthen your heart and lungs, improving the efficiency of the cardiovascular system.

Blood plasma volume increases with consistent distance running, and capillary density and mitochondria density increase. This helps improve your cardiovascular fitness level so that you can run longer distances more efficiently at a lower heart rate.

Your muscles become better able to extract oxygen and generate ATP, which is energy, using aerobic means.

Metabolic adaptations from proper training for your first half marathon or marathon help your body become better at burning fat for fuel at higher intensity levels. 

This helps conserve glycogen to prevent hitting the wall or running out of carbohydrates to burn in the later miles of the marathon.

Another benefit of training runs for your first marathon (or even your first half marathon if you’re a slower runner) is simply practicing your hydration and fueling strategy.

Running A Marathon Without Training: ALL The Reasons It's A Bad Idea 1

You have to get your stomach and digestive system accustomed to absorbing whatever type of hydration (sports drinks, water, electrolyte beverages, etc.) and carbs work for you to prevent stomach cramps, digestive distress, dehydration, electrolyte imbalances, and glycogen depletion during the marathon race.

One surefire way to have a poor first marathon experience is discovering that whatever energy gel or type of carbohydrates you decide to have during the race gives you terrible cramps.

Or, not understanding the proper timing and volume for hydration and carbohydrate intake before and during the marathon, such that you end up hitting the wall, doubled over with side stitches, having to walk, or not finishing the marathon.

Overall, running a marathon without training or minimal running experience is extremely ill-advised and not something any good running coach would recommend.

The same can be said for any extreme endurance event, such as an Ironman triathlon or an ultra marathon.

People running a marathon.

These races take at least 3-6 months of training for runners and triathletes who already have run longer races and have been running regularly and at least 6-12 months of training for beginners.

As I like to say, just because you can register for your first marathon—perhaps you get a last-minute charity entry to the New York City Marathon, Boston Marathon, or London Marathon—and get to the starting line having done zero training does not mean that you will get to the finish line.

Even if you do successfully complete a full marathon without training and get through the 26.2 miles on race day, you are likely not going to have a good marathon experience, and you may suffer long-term overuse injuries and put your health at risk.

Respect the marathon distance and go through a proper training plan, giving yourself months of training to prepare for a marathon race.

Be patient. The dedication to marathon training is sometimes the greatest part of the journey; the actual marathon race is just the celebration of all the work you have put in.

To get started today, check out our database of free marathon training plans for all fitness levels:

References

  • 1
    Wilson, M., O’Hanlon, R., Prasad, S., Deighan, A., MacMillan, P., Oxborough, D., Godfrey, R., Smith, G., Maceira, A., Sharma, S., George, K., & Whyte, G. (2011). Diverse patterns of myocardial fibrosis in lifelong, veteran endurance athletes. Journal of Applied Physiology110(6), 1622–1626. https://doi.org/10.1152/japplphysiol.01280.2010
  • 2
    Marathons damage the hearts of less fit runners for up to three months, MRI data suggest. (n.d.). ScienceDaily. Retrieved February 16, 2024, from https://www.sciencedaily.com/releases/2010/10/101025005836.htm
  • 3
    Day, S. M., & Thompson, P. D. (2010). Cardiac Risks Associated With Marathon Running. Sports Health: A Multidisciplinary Approach2(4), 301–306. https://doi.org/10.1177/1941738110373066
  • 4
    Wirnitzer, K., Boldt, P., Wirnitzer, G., Leitzmann, C., Tanous, D., Motevalli, M., Rosemann, T., & Knechtle, B. (2022). Health status of recreational runners over 10-km up to ultra-marathon distance based on data of the NURMI Study Step 2. Scientific Reports12(1). https://doi.org/10.1038/s41598-022-13844-4
  • 5
    Atkins, W. C., Butts, C. L., Kelly, M. R., Troyanos, C., Laursen, R., Duckett, A., Emerson, D. M., Rosa‐Caldwell, M. E., & McDermott, B. P. (2022). Acute Kidney Injury Biomarkers and Hydration Outcomes at the Boston Marathon. Frontiers in Physiology12. https://doi.org/10.3389/fphys.2021.813554
  • 6
    Ryu, J. H., Paik, I. Y., Woo, J. H., Shin, K. O., Cho, S. Y., & Roh, H. T. (2016). Impact of different running distances on muscle and lymphocyte DNA damage in amateur marathon runners. Journal of Physical Therapy Science28(2), 450–455. https://doi.org/10.1589/jpts.28.450
  • 7
    Lippi, G., Schena, F., Salvagno, G. L., Montagnana, M., Gelati, M., Tarperi, C., Banfi, G., & Guidi, G. C. (2008). Acute variation of biochemical markers of muscle damage following a 21‐km, half‐marathon run. Scandinavian Journal of Clinical and Laboratory Investigation68(7), 667–672. https://doi.org/10.1080/00365510802126844
  • 8
    Wirnitzer, K., Boldt, P., Wirnitzer, G., Leitzmann, C., Tanous, D., Motevalli, M., Rosemann, T., & Knechtle, B. (2022). Health status of recreational runners over 10-km up to ultra-marathon distance based on data of the NURMI Study Step 2. Scientific Reports12(1). https://doi.org/10.1038/s41598-022-13844-4
  • 9
    NILSSON, J., & THORSTENSSON, A. (1989). Ground reaction forces at different speeds of human walking and running. Acta Physiologica Scandinavica136(2), 217–227. https://doi.org/10.1111/j.1748-1716.1989.tb08655.x
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Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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