12 Mistakes I Made in My First Marathon (So You Don’t Have To)

No matter how much you train or prepare, your first marathon is always full of surprises. The long runs in training give you confidence, but nothing quite replicates the reality of race day — the nerves, the logistics, the 26.2 miles (or 42.2 kilometres) ahead of you, and the inevitable marathon mistakes that come with being a beginner.

To make things even harder, in the days leading up to my first marathon, I came down with a nasty cold, which added another layer of challenge.

Between being sick and being inexperienced, I basically ticked off almost every beginner marathon mistake possible. The good news is that these are common pitfalls many first-timers make — illness or not — which means you can learn from them and (hopefully) avoid repeating them during your debut marathon.

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12 Beginner Marathon Mistakes to Avoid

From pacing and fuelling to race-morning logistics, there are plenty of ways a first marathon can go off track. These are the marathon mistakes I made in my debut — and the lessons that will help you avoid them.

1. Running While Sick

Because I was sick during race week, I lined up feeling far from my best. Fortunately, the headache and chills had gone, but on race morning I was still dealing with congestion, a sore throat and fatigue from several nights of hardly any sleep. However, as my symptoms were all “above the neck“, I decided to still run the marathon.

My sub-4 hour goal was gone, and I shifted my focus to simply finishing, which I did, in 4:13, but recovery was rough — my body had to repair muscle damage while still fighting off illness, which dragged out the healing process.

Getting sick during taper is actually pretty common: you’ve reduced training, your immune system is more vulnerable, and stress levels are high. To minimize the chances, focus on getting lots of sleep, eating well, and avoiding large crowds and other people who are sick.

If you’re unfortunate like me and do catch something before your race, consider whether it’s smarter to skip this one and sign up for a marathon a few weeks later instead. It might feel crushing at the time, but running healthy means you’ll perform better — and give yourself a much better shot at reaching your goals.

2. Not Carb Loading Properly

Going in to my first marathon, I knew about carb loading, but I didn’t truly understand what this meant. Plus, because I was sick, my appetite disappeared in the days before the race.

As a result, I barely ate and consumed only a fraction of the carbs I should have. Then, the day before the marathon I stuffed myself with carbs – largely noodles, rice and bread – as if that would make up for it. Of course, it didn’t.

Proper carb loading isn’t about one big pasta meal — it’s about steadily topping up glycogen stores for 2-3 days leading into the race. Because I hadn’t fuelled properly that week, I lined up with lower energy reserves than I should have — and it caught up with me in the final stretch.

3. Skipping Breakfast on Race Morning

To make matters worse, I skipped breakfast altogether on race morning. I didn’t get up early enough to comfortably digest a meal before the start, and although I had planned to at least have a snack, I just didn’t have an appetite. I managed a coffee, but that hardly made up for the lack of food.

Breakfast is your final chance to top up glycogen reserves and start the race with maximum energy — an opportunity I completely wasted. Combined with my failed attempt at carb loading, this likely played a big role in why I bonked in the last quarter of the race.

These days, I always eat something before a race, even if it’s small — a bagel, toast, or a banana — and I’ll often take a sports gel just before the start for an extra boost.

4. Eating a Heavy, Late Dinner

We stayed overnight close to the race, but arrived late the night before and didn’t sit down to eat until around 9pm. The only real option nearby was Indian food — delicious, and even helpful for clearing my congested sinuses — but not exactly the ideal pre-race dinner.

Digesting a heavy, spicy meal overnight is far from optimal, and I definitely didn’t feel as light or fuelled as I could have the next morning.

Now, I make sure to eat my heavier meals earlier in the day before a race, and keep dinner safe and simple with something bland, carb-heavy, and easy to digest — like rice and eggs or a bowl of cereal.

5. Not Fuelling Enough During the Race

The final fuelling mistake I made was during the marathon itself. I did take some gels and chews, but nowhere near enough — which definitely contributed to me hitting the wall at kilometre 36. I also didn’t take in any real electrolytes, apart from the occasional mouthful of Gatorade from aid stations, which wasn’t close to meeting my needs.

For long distances, the general recommendation is 60–90 grams of carbs per hour to keep glycogen levels steady. These days, I start fuelling early, taking a gel every 25 minutes, along with electrolyte tabs or chews.

Fuelling mistakes are almost a rite of passage for first-time marathoners, but having a clear plan makes a huge difference in how strong you feel in the later stages.

6. Starting Too Fast

Like so many first-time marathoners, I got caught up in the excitement and made one of the most common marathon mistakes: going out far too fast. In fact, I even ran a half marathon personal best in the first half of the race, which was a clear sign that I had messed up.

From there, my pace slipped steadily, and by kilometre 36 I had completely burned through my energy reserves. The final 6 kilometres turned into a very slow, painful grind.

Pacing is everything in the marathon. Even splits — or better yet, negative splits — are the key to finishing strong.

One of the best ways to avoid starting too fast is to run with a pacer: they’ll hold a steady rhythm from start to finish so you don’t have to worry about checking your splits. And if your goal pace feels too easy in the early kilometres, that’s exactly how it should feel.

7. Wearing the Wrong Shoes (and Socks)

At the time, I didn’t know much about running shoes. I simply wore my everyday Nike Pegasus trainers, which had gotten me through my long runs in training. They did the job, but they definitely weren’t the fastest or most comfortable option I could have chosen for the distance.

I also ended up with hot spots and rubbing under my feet — likely caused by the brand-new socks I decided to wear on race day (another rookie mistake). While they’ve since become fantastic running socks, I hadn’t tested them before the race — they hadn’t even been washed yet. Combined with my less-than-ideal shoe choice, they rubbed more than they should have over 42.2 km.

These days, I take the time to choose proper race shoes, trying different styles and sizes to find the best fit — and always testing them in training before race day. I’ve also learned that I need to size up slightly in marathon shoes to allow for foot swelling during the race, a small adjustment that has made a big difference. In fact, I’ve since ran marathons with completely blister-free feet.

Even if you’re not interested in carbon-plated “super shoes,” having the right race-day shoe — along with socks you’ve already tested — can make a huge difference in comfort and efficiency over the marathon distance.

8. Overdressing (and Choosing the Wrong Layers)

It was a chilly 7–10°C race morning, with drizzle and overcast skies. Because I was sick and feeling extra sensitive to the cold, I dressed in leggings, a long-sleeve top, and a lightweight jacket.

While I didn’t overheat (although I probably would have if I hadn’t been sick), I did find myself constantly adjusting my leggings during the run — they tend to slip down on me while running — which quickly became distracting. I’ve since learned that running shorts are often far more comfortable for races, even in cooler weather, since they don’t shift or rub the same way over long distances.

One of the biggest lessons I’ve learned since then is that runners should almost always dress as if the temperature is about 10°C warmer than it actually is. Once you start moving — especially in a marathon — your body generates a lot of heat, and overdressing can quickly lead to overheating and discomfort.

It’s also important to pay attention to the “feels like” temperature, not just the actual air temperature. Wind, rain, and humidity can all change how conditions feel on race day, which can affect your clothing choices.

These days, I stick to lightweight layers and gear I know will stay comfortable for hours. If it’s cold at the start, I’ll often wear a throwaway layer that I can discard once the race begins. This is common practice at marathons — on chilly or rainy start lines, you’ll often see runners wearing old sweaters, cheap ponchos, or even bin liners to stay warm before the gun goes off.

9. Forgetting Anti-Chafing Balm

Until you’ve run 42.2 km, it’s hard to imagine just how much your clothes can rub — and forgetting anti-chafing balm is another one of those beginner marathon mistakes you don’t think about until it’s too late.

By the end of the race, I had chafing in places I didn’t know could chafe. At the time, I’d seen the viral photos of male marathoners with bloody nipples, and I knew I was prone to chafing on my arms and thighs in hot weather, but I didn’t think it would be an issue for me during the marathon. I hadn’t even heard of Body Glide or anti-chafing balm!

While I was lucky that my chafing issues that day were fairly minor, I did discover how uncomfortable sports bra chafing can be — and I’ve had some much worse experiences with it since. Now, I never start a race without applying Body Glide anywhere I might chafe, just in case. It’s a small detail, but it can make a huge difference in how comfortable you feel over 26.2 miles.

10. Relying Too Much on Music

Back then, I couldn’t run without music — or so I thought — so I raced with earbuds in and my phone in my pocket.

During the marathon, though, the earbuds kept slipping, batteries died, and I found myself slowing down or even walking to fix them. It broke my rhythm and quickly turned into more of a distraction than a motivator. And while carrying a phone doesn’t seem like a big deal, it’s still an extra item you really don’t need to juggle during a race if you can avoid it.

These days, I often run without music at all — opting instead for podcasts in training or simply the sounds of the race itself. I’ve even run events lasting over 12 hours in complete silence without missing it.

If you do prefer to run with music, invest in reliable headphones, prepare your playlist in advance, and consider using one earbud at a time to avoid mid-race battery issues. And keep in mind that some races don’t even allow headphones at all, so it’s always worth checking the rules before you start training with them.

11. Struggling With Aid Station Cups

The pros might make drinking from little paper cups while running look easy, but it really isn’t. During the race, most of the water ended up down my front instead of in my mouth. Only afterward did I learn the trick of pinching the cup to create a spout — which definitely helps, but still isn’t foolproof.

Since then, I’ve practiced drinking on the run and gotten a bit better at it, but it’s still not my favourite. So, these days I’ll sometimes carry a handheld bottle instead of relying on aid stations — it takes the stress out of hydrating mid-race, and lets me drink more comfortably on my own terms.

12. Cutting It Too Close on Race Morning

Because I was exhausted from being sick, I let myself sleep in as late as I could on race morning, and we only arrived at the start about 30 minutes before the race. Between bib pickup, bathroom lines, and nerves, I felt rushed and stressed heading into the start. It was enough time, but only barely.

Honestly, this is a mistake I still struggle with — I’m still pretty bad at giving myself extra time before races, causing me to get unnecessarily stressed and not have enough time to do everything I’d like to before the start, like warmup, have a snack, or even take some photos. But it’s something I continue to work on, because the calmer you can be on race morning, the better your day will go.

Final Thoughts – Marathon Mistakes

Despite being sick, under-fuelled, overdressed, and going out too fast, I still crossed the finish line of my first marathon in a time I was proud of. It wasn’t perfect, but pushing through taught me lessons I’ve carried into every race since.

If you’re preparing for your first marathon, focus on fuelling smart, stick to your plan, practice your race-day logistics, and keep things as simple as possible. You’ll make your own marathon mistakes — we all do — but hopefully fewer than I did!