Can You Run a Marathon If You Can Run a Half? What It Really Takes

Finishing a half marathon feels awesome—no doubt. Once you’ve got that under your belt, going for a full marathon seems like the natural next step. But is it actually that simple? The leap from 13.1 to 26.2 miles is no small jump. It’s more than just running twice the distance; you’re dealing with a whole new set of challenges, both in your body and your brain.

If you’re thinking about bumping up to a marathon, you’ll need to rethink your strategy. Long runs get longer, recovery takes on a new level of importance, and fueling becomes non-negotiable. Many runners are surprised how sneaky the difference really is—cruising through 13.1 miles doesn’t guarantee things will go smooth at mile 20 in a full marathon. That’s where most first-timers hit the dreaded wall, and it can make or break your race.

The good news? Plenty of people have made that jump—and they started right where you are now. With the right plan, a dose of patience, and a few smart adjustments, you can absolutely go from half marathon hero to marathon finisher. It just takes a bit more time and the right tweaks to your routine.

• The Big Leap: Half vs. Full Marathon
• What Changes in Training
• Physical and Mental Challenges
• Common Pitfalls and How to Dodge Them
• Tips for Making the Jump Successfully

The Big Leap: Half vs. Full Marathon

So you’ve crushed a half marathon and now you’re eyeing a full one. Point-blank: a full marathon and a half marathon aren’t just distances on a map—they’re completely different challenges. A lot of folks figure you can just double what you did for the half and you’re good. Reality check: that’s not how it works.

Here’s the main thing—running 13.1 miles is tough, but running 26.2 is a different beast for your legs, heart, and head. You’re not just dealing with an extra hour or two on the course. Your risk for hitting the wall or bonking (that exhausted, out-of-gas feeling) goes up big time. The marathon is a test of both your physical endurance and your mental stubbornness.

Let’s talk numbers. According to race data in the U.S. from 2023, almost 2 million people ran a half marathon, but only about 500,000 finished a full marathon. It’s not because people don’t like the challenge; it’s because the gap is wider than most think.

On average, the marathon isn’t just double the time—it’s more. Your pace usually slows, and you need to prepare your body for the longer hours on your feet. Recovery time after a marathon is also way longer than after a half.

Key differences between the two? Let’s break it down:

• Training Load: Weekly mileage for marathons jumps. Full marathon training usually means 35-50+ miles per week. For halves, it can be 20-30.
• Long Runs: Your long runs get way longer—with some marathon plans topping out at 20 miles. Half marathon training rarely goes past 12-13 miles.
• Fueling and Hydration: In a half, you can sometimes get by with just water and a snack. In a full marathon, you need a solid plan for gels, sports drinks, and water or you’ll crash.
• Injury Risk: Longer training sessions mean more opportunity for overuse injuries. You have to get serious about recovery and mobility.

Bottom line: If you handled a half, you’re off to a great start. But don’t underestimate the jump to a full marathon. It’s tougher, it’s longer, and it demands more—but crossing that finish line is like nothing else in marathon training.

What Changes in Training

Jumping from a half marathon to a marathon means your training has to level up, too. You won’t just do a bit more—you’ll face totally different demands. Most half marathon plans cap the long run at about ten miles. Marathon plans? You’re looking at 18 to 22-mile long runs, and those weekends add up.

Your marathon training also needs a sharper focus on fueling. During a half, you might get by with a quick gel or even nothing at all. But on a full, you have to practice eating and drinking on the go, or you'll feel wiped out far before the finish line. Nailing your nutrition and hydration becomes a new top priority.

• Weekly Mileage: Expect your weekly miles to climb. Instead of 25-30 miles a week (half marathon average), you might see 40+ miles on your peak marathon weeks.
• Training Frequency: Most marathon plans ask for 4 to 5 runs per week. Cross-training days and full rest days matter even more—your body needs them to keep up.
• Long Runs: These go much longer. You’ll spend hours on your feet, which is its own skill and big wear-and-tear for your legs.
• Back-to-back Hard Days: Marathon training often has you run longer on tired legs. This builds endurance that a half marathon just doesn’t require.
• Pacing Practice: Pacing becomes way more important. Go out too hard in a marathon, and it’s game over halfway through.

Here’s a quick comparison of a typical training week for each distance:

Also, don’t underestimate recovery. With the extra miles and longer long runs, your legs will need more time and smarter strategies (think cold baths, foam rolling, maybe even massage guns). So, yes, you can run a marathon after a half—but only if you commit to bigger, smarter training. Your body (and your finish line photo) will thank you.

Physical and Mental Challenges

Moving from a half marathon to a full marathon changes the game, both in your body and in your head. The biggest hurdle? Endurance. Your legs face twice the pounding, and that toll adds up faster than most expect. Muscle fatigue and aches that show up in the last few miles of a half can flare up much earlier—and stick around much longer—during a marathon.

It’s not just about muscle pain. You’re looking at a bigger risk for blisters, chafing, and dehydration. According to a 2023 survey from Running USA, nearly 40% of first-time marathoners reported hitting "the wall" between mile 18 and 22. That’s when your glycogen stores drop and every step feels brutal. Your energy dips, your head gets cloudy, and you start doubting your decision to even sign up.

The mental part is a whole battle of its own. You’ve got hours out on the road, and it’s easy for negative thoughts to creep in, especially once things get uncomfortable. Many runners hit a slump just from the grind of training. Burnout is real—if you’re not careful with your rest days, you could find yourself exhausted before you even get to the starting line.

• Training for a full marathon means learning to listen to your body’s warning signs, not just pushing through pain like in a shorter race.
• Your sleep, nutrition, and hydration move from “important” to “absolutely critical.” Recovery strategies—like foam rolling, stretching, and even regular sports massages—start making a real difference.
• The long runs of marathon training can mess with your head. Pacing yourself, fighting boredom, and keeping up motivation get a lot harder during 18+ mile outings.

Here’s a snapshot that compares typical physical and mental hurdles between the two races:

Bottom line: Doubling the distance means really upping your physical care and building new mental endurance skills. Marathon day rewards the runners who show up prepared on both fronts—not just those who could handle a half marathon a few months back.

Common Pitfalls and How to Dodge Them

Nearly every runner eyeing their first full marathon after a half marathon runs into the same classic blunders. Knowing what trips people up is half the battle. Let’s break down what usually goes wrong—and how you can sidestep these traps.

1. Skipping the long runs or not running them long enough

This is the big one. In marathon training, long runs should be your bread and butter. Cutting them short or, worse, skipping them because you feel tired or busy will almost always come back to haunt you. The body needs time to get used to distances over 13 miles, both physically and mentally. The long run is where your legs and mind start building real endurance for the last brutal six miles of the marathon.

2. Ignoring nutrition and hydration

Fueling isn’t an afterthought for a marathon. Finishing a half marathon might be doable on willpower alone, but you’ll hit a hard stop around mile 18 if you don’t eat and hydrate right. Bring gels, chews, or whatever sits well on your stomach—and practice during training, not just on race day. Dehydration or bonking from low carbs is the fastest way to end race day fun.

3. Not respecting recovery

Marathon training taxes your body in a way a half marathon never did. Injuries from overtraining, running through pain, or ignoring rest days are common. Take recovery days seriously. Listen to little aches and pains before they become bigger issues. Real rest can mean the difference between lining up healthy or nursing a stubborn injury come race day.

4. Pacing mistakes

Here’s where ego can get you. Many runners head out too fast, using their half marathon pace, thinking it’ll work for the full distance. It almost never does. Use long runs to find your real marathon pace—the one you can actually keep up for 26.2 miles, even if it’s much slower than you want. Miles 20-26 are a totally different ball game if you don’t.

5. Underestimating the mental side

Muscles might quit first, but your brain is usually the real boss in marathon running. Hitting “the wall” is a real thing—often between miles 18 and 22. If you haven’t mentally rehearsed working through boredom, discomfort, or those doubts that creep in late, you risk breaking down when it matters most. Visualization, mantras, and just being ready for discomfort can really help here.

• Respect your long run schedule—don’t skip it.
• Dial in your nutrition and hydration plan early.
• Take at least one full rest day a week.
• Practice marathon pace every weekend, not just in races.
• Find mental tricks that help you press on when it gets tough.

Check out the numbers: a 2023 study from RunRepeat showed over 36% of new marathoners struggled because they either started too fast or had fueling issues during their first race. This stuff is super common—even if you feel prepared.

Learn from the crowd, not just your own mistakes. If you nail your training plan and keep these common pitfalls in check, you’ll toe the line ready for your best shot at that finish line.

Tips for Making the Jump Successfully

Making the move from a half to a full marathon isn’t about just adding miles. It’s about building smart habits, understanding your body, and tweaking what already works for you in marathon training. Here’s what really helps if you want to finish strong and not just survive the race.

• Extend Your Long Runs Gradually: Don’t double your longest run overnight. Bump up your long run distance by about a mile every week or two. Most first-timers aim for at least one or two 20-mile long runs before race day, but you don’t need to run the full 26.2 in training.
• Dial In Your Nutrition: Fueling during a half marathon isn’t as critical, but for a marathon, it’s a game-changer. Practice eating and drinking on your long runs to find what settles best. The sweet spot? Aim for 30–60g of carbs per hour. Miss this, and you’ll likely hit the wall.
• Don’t Ignore Recovery: Longer miles stress your body more. Toss in more stretching, foam rolling, and actual rest days. Good sleep helps you go longer, and keeping injuries away is half the battle.
• Prioritize Consistency Over Intensity: It’s better to run steady miles week after week than to go all-out one week and crash the next. Consistent weekly mileage—most experts suggest 30–40 miles a week for first-time marathoners—pays off more than occasional hero days.
• Do Dress Rehearsals: Use at least one of your longest runs to copy what you plan for race day—shoes, clothes, breakfast, fueling. Surprises make for bad race days.
• Strength Training Matters: Two short sessions a week can keep your hips and core solid, and less likely to ache at mile 20. Bodyweight squats and planks help most runners; you don’t need a fancy gym setup.

It’s also good to know just how much training shifts between half and full. Here’s a quick comparison:

If you lay the groundwork with smart running tips and honest training, going from half marathon to marathon is totally doable. Listen to your body, stick to the plan, and you’ll cross that finish line with more than just luck on your side.