6 Tips For Running A Marathon when Undertrained and Underprepared

Feeling undertrained and underprepared for an upcoming marathon? We’ve all been there.

For most novice and amateur runners in the world, the lead-up to a race can be nerve-racking and full of doubt.

If you’re panicking that you’re not ready for an impending marathon, and are looking for some tricks and tools last minute, then fear not – we’ve got just the thing.

There are many ways to run a marathon when you are undertrained and underprepared, and all of them are about conserving energy and taking your time.

As the old adage goes, ‘It’s a marathon, not a sprint.

Consider this a race survival guide, whether it’s your first marathon or marathon training hasn’t gone to plan. It will guide you through the ways of getting to the finish line of the marathon—and if you are patient enough, get from the start line to the finish line with a smile on your face.

This survival guide will discuss 6 tips and tools:

  • Pre-race nutrition
  • The Run/Walk Technique
  • Finishing Times
  • Rate Of Perceived Effort/Exertion
  • Enjoyment

. . . along with some other tips and tricks along the way.

So read along and put your mind at ease!

how to run a marathon when undertrained and underprepared 1

#1: Pre-race Nutrition

The overarching theme of this whole piece is the art of saving energy.

Your body loves to run on glucose, which is the main energy for the body.

It is stored in your body as glycogen. Glucose is energy derived from sugar and carbohydrates. It is fast-release, meaning when you body needs it, it is available to you almost straight away.

If you are a runner, you may have heard of the term ‘Carb Loading’, which is a way of getting your muscles glycogen stores as full as possible on the lead up to the race, so on race day, you have as much fast-release energy as you can possibly get.

Once you run out of glucose and glycogen, your body starts to utilize fat as fuel. This is much more inefficient and often makes you feel sluggish, heavy, and slightly sick.

It can also lead to ‘hitting the wall‘ and bonking (having no energy in the tank and your legs sometimes feeling too weak to even walk). As a seasoned runner, I can tell you bonking is no joke.

If you are running a marathon in ‘survival mode‘ then it is very important to try and keep using your glycogen stores for as long as possible to avoid bonking.

how to run a marathon when undertrained and underprepared 5

#2: Mid-Race Nutrition

So, you want to keep burning glucose or carbs for as long as you can throughout the full marathon.

As well as stocking up on carbohydrates before the race, you can also stock your glycogen stores during the race.

Energy gels and sports drinks contain high levels of it in an easy-to-digest way.

So, we are going to take a leaf out of the ultra-running handbook again here. During your periods of walking, keep eating!

Do not eat too much; otherwise, you will get a stitch or cramp, but keep snacking on energy gels, chocolate bars, or sports drinks (this will double as hydration, too).

This will replenish your energy and nutrient stores, stopping your body from using your fat stores instead of trusty glucose.

For what to eat pre, during and post-run check out our complete nutrition guide.

how to run a marathon when undertrained and underprepared 4

#3: Use The Run/Walk Technique

A great way of keeping your energy levels high is by going slow.

The run/walk technique is a great way of keeping your pace manageable while also giving your body lots of energy-saving walk breaks throughout the marathon.

You will often see ultra runners using the same technique to cover the massive distances of an ultramarathon. If it works for them, it will work for you.

Break up your marathon into 1-mile walking sections and 4-mile running sections.

The chances are that you will be capable of running the first 4 miles (1 mile is approx 1.6km) without much of a sweat. Then, give yourself a walk break for a mile. Then run 4 miles and walk another 1 mile, and so on.

Each time you walk you will lose around 5-10 minutes for that mile, but it will be much more time-efficient than lying in a bush with a DNF waiting for someone to pick you up.

The important thing to remember is that you are in the race for the long game. The first break may seem too easy, but be patient – remember there are over 20 miles to go. So, walk the whole mile, nice and steady, and don’t overdo it.

You will not win the marathon with this technique but we are here to finish, don’t worry about your time.

how to run a marathon when undertrained and underprepared 6

#4: Forget about Finishing Times

The clock at the end of the race. This can often be the downfall of many runners.

When undertrained, your focus in the race should be on finishing injury-free, rather than finishing at a particular time.

Yes, the elite athletes have a specific time they want to beat, but for the normal runner, you are racing against yourself, not the clock.

This can be difficult to understand, especially if you are competitive. Ignore the pace of those around you. As runners run past you, say “hello,” but don’t find yourself getting pulled along with them.

You have no idea how much training they have done in the past, so keep focused on your own race.

I have seen a lot of first time and veteran runners in my time chasing other runners, and within a few miles, they realise slightly too late that they have pushed too hard and are running on steam.

At this point, they always slow to a crawl, and they would have been better off sticking to their race day plan and running their own race pace.

how to run a marathon when undertrained and underprepared 7

#5: Try Rate Of Perceived Effort (RPE)

The rate of perceived effort / exertion is personal to you.

It is how hard you find a specific task or activity. One way of gauging your RPE is by using your smartwatch, which measures your heart rate.

For instance, a 100m sprint has a very high RPE as it is high intensity, vs a walk that has a low RPE as it is low intensity.

During a marathon, you want to keep your RPE quite low. The lower your RPE the easier you will find your marathon.

Your heart is an easy telltale sign of how hard your body is working. If you have a heart rate of 170 BPM (beats per minute) then your body is working very hard so it is time to slow down and ease off, maybe consider a walk break.

In general, during your run, you should aim to have a heart rate of around 130-140 BPM.

You should be relaxed and be able to keep going for a lot longer. However, don’t get too focused on these numbers – listen to your body and let that guide you too.

how to run a marathon when undertrained and underprepared 8

Heart Rate Zones:

Zone 1 (50-60% Of Maximum Heart Rate or MHR)- Rest

Zone 2 (60-70% of MHR)- Easy, similar to a training run

Zone 3 (70-80% of MHR)- Aerobic, what you might feel during a longer workout (You will start to feel your muscles working here but you will not be feeling the burn yet)

Zone 4 (80-90% of MHR) – Anaerobic, what you might feel during a speed workout (This is the burning feeling of lactic acid build up in your muscles. This type of exercise is unsustainable for a prolonged time)

Zone 5 (90-100% of MHR)- Maximum Effort

Depending on your age and fitness, the easy way of predicting your MHR is subtracting your age from 220 (so if you were 20 years old your MHR would be 200).

If you do not have a watch, then use ‘body sensing‘. – If the run seems hard, then slow down to a walk. As you recover and everything feels easier again then maybe start running again.

#6: Enjoy it!

how to run a marathon when undertrained and underprepared 2

Enjoyment may seem like an odd one to put in here, but it has a very important place in your run. It’s normal for marathons to be physically and mentally straining, so try to run in a way that prioritizes your enjoyment.

This will not only protect your mood, but actually causes physiological changes that will help you complete your run. Good-mood endorphins like oxytocin are released when you’re happy and smiling – and these endorphins are linked to improved stamina and performance.

Even if you are completely out of energy and your running shoes feel heavier than bricks…

…you can walk the whole thing and still finish! Lots of people walk a marathon. Remember it’s the distance that is the challenge, not the time.

When you finish the race you will feel the same level of accomplishment as the person who finishes in 3 hours, everyone there is there to run 26.2 miles at the end of the day.

Remember – completing a marathon when underprepared is just as impressive as completing a marathon when fully trained.

Just keep going and keep smiling 🙂 You can do it!

We haven’t spoken about sleep in our tips, but this is another key component to running a marathon when underprepared and undertrained. Read our sleep guide here.

how to run a marathon when undertrained and underprepared 9

Looking for a way to prepare for a Race?

These tips on how to run a marathon when undertrained and underprepared are great, but the best cure for pre-run dread is prevention.

For the failsafe way to prevent turning up to a race unprepared, check out our training plans.

Photo of author
Tom McMeekin-Donnelly is a runner, outdoor enthusiast and cyclist. Tom competes in ultra-marathons in the UK and Ireland. Tom runs anything from a marathon to 100 miles. He can often be found in the mountains around his home in Ireland.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.