First Marathon: Mistakes Everyone (or Almost Everyone) Makes
Your first marathon is a unique adventure. No theoretical training can truly simulate what you'll feel over 26.2 miles (42.195 km). However, some mistakes are so common that they can be anticipated—and avoided. Here are the most frequent ones, with a few nuances, because what's a mistake for one runner might work for another.
1. Starting Too Fast
The number one mistake. The one that causes the most damage. Race day adrenaline, the crowd, the cheers—everything pushes you to run faster than planned. The result: your glycogen stores deplete too early, and the wall hits at mile 17 (km 28) instead of mile 22 (km 35). The solution: know your target pace and stick to it strictly for the first 6 miles (10 km), even if it means getting passed. It's tough on the ego, but it pays off.
2. Neglecting Long Runs
Marathon training is built over weeks, not on brilliant interval sessions. Long runs (90 minutes to 2 hours 30 minutes at an easy pace) are the cornerstone of your prep. They train your body to burn fat, strengthen tendons, and mentally prepare you for the distance. Skipping them due to lack of time is a shortcut to suffering on race day.
3. Trying New Fuel on Race Day
An unknown gel at mile 12 (km 20), an isotonic drink your stomach can't handle: digestive issues are one of the leading causes of DNF (Did Not Finish). Every fueling product must be tested in training, period. I've seen people drop out because of this; it's such a shame.
4. Wearing Brand-New Shoes
Those super carbon-plated shoes bought three days before the marathon might seem like a good idea—until the blisters hit at mile 9 (km 15). Every race shoe needs to be broken in over at least 2-3 long runs. Golden rule: nothing new on race day.
5. Ignoring the Weather
Temperature has a direct impact on performance. A marathon at 77°F (25°C) is entirely different from one at 54°F (12°C). Expect a 2-5% slowdown above 68°F (20°C). Adapting your pace to the weather isn't weakness; it's smart strategy.
6. Doing Too Much the Last Week
The fear of “losing fitness” drives some runners to train hard until the very end. Big mistake. The last week (or even two) is all about tapering: reducing volume by 40-60%, while maintaining intensity with shorter sessions. This phase is when your body rebuilds and prepares to perform at its peak.
7. Setting an Unrealistic Goal
Aiming for a “sub-3:30” for your first marathon when you've run a half-marathon in 1:55 is risky. Race time predictors give you a reasonable estimate. My advice: for a first marathon, aim for 5 to 10 minutes slower than the prediction. You'll thank me at mile 22 (km 35).
8. Poorly Managing Hydration
Both extremes pose problems. Not drinking enough → dehydration. Drinking too much → risk of hyponatremia. The simple rule: drink to thirst, regularly, without forcing it.
9. Underestimating the Mental Game
The marathon is as much mental as it is physical. Moments of doubt often strike between mile 15.5 (km 25) and mile 22 (km 35)—a zone many have never experienced in training. Mentally preparing yourself, having mantras, breaking the race into segments can make the difference between a happy finish and dropping out.
10. Not Enjoying the Experience
Your first marathon only happens once. Focusing solely on your time can spoil the moment. The crowd, the scenery, the feeling of crossing the finish line: these moments are worth just as much—if not more—than a few shaved seconds. Enjoy it.
My takeaway: your first marathon is a learning experience. Making a few mistakes is part of the game. But the most costly errors—starting too fast, untested fueling, an unrealistic goal—are also the easiest to avoid with minimal preparation.
Frequently Asked Questions
What is the most common mistake in a first marathon?
Starting too fast. The euphoria of the start, the crowd, and adrenaline push runners to go 15-30 seconds too fast per km, which exacts a heavy toll after the 30th km.
Should you test your gear before the marathon?
Absolutely: shoes, socks, apparel, and fueling. Everything must be tested on long training runs. Nothing new on race day.
How many weeks of preparation for a first marathon?
12 to 16 weeks minimum, with a prior base of 3-6 months of regular running (3-4 runs/week) and the ability to run 90 minutes without difficulty.