What is the marathon ‘wall’ and how do you avoid it?

Mary Jennings: I’ve yet to hit the wall in my many years of marathon running, you can train your body to avoid it

The biggest fear of a marathoner is an encounter with “the wall” on race day. Without knowing what exactly “hitting the wall” means, it’s the reason many runners never consider taking on the distance. Those in training can spend months anxious about this infamous wall making an appearance on race day, but it doesn’t have to be that way. You can train your body to avoid encountering the wall.

What exactly is the wall?

We power our run on glycogen, which is basically the energy fuel the body creates from the food we eat and the fat we have stored in our body. In simple terms, when this energy runs low, the body moves into self-defence mode, prioritising the operation of our vital organs ahead of our running muscles. Basically, we run out of gas and the body has to slow down to generate more fuel. From a runner’s perspective physical and mental energy fades. We can feel weak, dizzy and ultimately our pace, focus and performance decreases. Moving forward becomes a serious challenge. If you have watched the latter stages of a marathon you will probably be able to remember a few runners who had followed this path. It doesn’t sound tempting but it is certainly something you can prepare your body to avoid.

The alternative to the wall


I’ve yet to hit the wall in my many years of marathon running, but I have always been cautious about running within my limits and respecting the marathon distance. Some might say I don’t push my body to its peak capability. But for me, finishing strong, enjoying the day and challenging myself within my limits has always worked and kept my love for the distance. Being able to maintain mental strength, running posture and a positive attitude in the later stages of a marathon is a powerful feeling. If you are first-time marathoner, focus on working within your limits rather than letting your pace be dictated by an arbitrary time goal. Without the pressure of the clock you will reduce the anxiety, stress and the pressure to keep to a certain speed when your body might be telling you that it is too fast. Erring on the side of caution is a wise strategy for someone who wants to finish with a smile.

Two secret weapons

From over a decade of coaching runners to enjoy their marathon experience, I have found that there are two key practical elements of training that help runners manage energy and nerves on marathon day. The combination of knowing their optional running pace with a well-practised fuelling strategy can change a marathon experience from one which feels like an experiment to a more controlled, disciplined and relaxed challenge. Ideally we want to drip feed our energy throughout the 42.16km (26.2 miles) and run at a pace that allows our body to convert our food to glycogen for when we need it. The last thing we need is to waste even more energy on second-guessing our decisions and wondering if we have done enough.

Practice every week

So what is the perfect pace and the best food strategies for you to build into your marathon plan? The truth is that it is all individual but you have an opportunity every week to fine-tune your marathon menu and experiment with what works for your running body. From gels to sweets, dried fruit to bars the on-the-go food choices are endless. Some stomachs are more sensitive than others. So decide what works for you now (via trial and error) and then come up with a strategy for how regularly you top up your fuel tank. Personally every 3 miles I look forward to having a bite or two. Little and often regularly from the start will keep your energy up and your mind focused and alert.

Mind your pace

If you can combine your food of choice with the right running pace to allow your body to process the food, you are on for a comfortable run. Each week you should have a long run to learn to manage your speed. Aim to run at a comfortable, relaxed and conversational pace. This is the best pace to allow your body convert fat to fuel on the go as it has oxygen at the ready. This extra source of energy from fat supplements the food you have taken in before and during the run. Please don’t run your long runs at the pace you expect to be running the marathon. Even the best elite athletes will run the “long runs” slower than race pace. Training for endurance is not about pushing speed limits in long weekend runs. Get your speedy fix in some midweek short runs instead.

Experiment now

By the time marathon day comes around you will have another 8 weeks of long-run experiments behind you. All the questions you have will be answered and you will have the confidence and experience to alleviate the fears you have now. You will have fine-tuned your marathon menu and worked out an optimal marathon pace you can sustain. You will have made a few mistakes along the way but these will bring great lessons. You will be a completely different runner by the time marathon day comes around so don’t waste your time wondering about what might happen. Consider instead each long run as a trial run for your marathon, an opportunity to experiment, learn and build self-belief so no decisions are left to race day and you can focus on truly enjoying your marathon day out. For now, just take it all one week at a time and trust it will all come together in the end.

— Sign up for one of The Irish Times’s Get Running programmes (it is free!) First, pick the eight-week programme that suits you.

  • Beginner Course: A course to take you from inactivity to running for 30 minutes.
  • Stay On Track: For those who can squeeze in a run a few times a week.
  • 10km Course: Designed for those who want to move up to the 10km mark. Best of luck!

Mary Jennings is founder and running coach with ForgetTheGym.ie