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An running outside as part of Peloton's marathon training plan.

How to Train for a Marathon at Every Level

Peloton instructor and competitive marathon runner Becs Gentry weighs in on everything you need to know before you run the iconic distance.

By Jennifer HeimlichUpdated 10 July 2025

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So you’ve decided to take the plunge and sign up for a marathon. Congrats! When you cross that finish line, you’ll become a member of an elite club. “Only around one percent of the world's population run a marathon,” points out Peloton instructor Becs Gentry, a competitive marathon runner.

There’s a reason why it’s so rare: Marathons are incredibly challenging endurance events that take serious dedication. So how should you prepare for it?

We gathered all the marathon training info you need to know to get to that starting line feeling ready—and excited—to conquer the course, including a ready-made marathon training plan from Peloton that makes it easy to get started.

How Long Is a Marathon?

A marathon is 26.2 miles or about 42 kilometers. The race is based on the legend of the Greek messenger Pheidippides, who ran about 25 miles from a battlefield in the town of Marathon to Athens in 490 BC to announce a Greek victory over the invading Persians. According to the History Channel, the modern-day marathon distance is based on the 26.2-mile course from the 1908 London Olympics, which began in front of Windsor Castle and ended at the Olympic Stadium in front of the royal box. 

How Many Months Do You Need to Train for a Marathon? 

How long it takes to train for a marathon depends on your current fitness level and previous experience as a runner, according to Becs. Another important factor to take into consideration is your personal time commitment level, she adds. If you anticipate daily life, travel, or work getting in the way of your training, give yourself some extra weeks, so you have a little leeway if you miss a run here or there. 

  • Beginners: 12 Months. Pretty new to running? You’ll want to slowly work your way up to the marathon distance. “The recommendation for beginners to train for a marathon is about a year,” says physical therapist Palak Shah, who works with runners as the head of physical therapy services at Luna, an at-home therapy provider. This gives your body time to build cardiovascular endurance and adjust to the demands of the sport gradually so you can decrease your risk of overuse injuries when you’re racking up mileage.

  • Intermediate to Advanced Runners: 4–6 Months. Once their legs are used to longer runs, most runners will follow a dedicated marathon training program for anywhere from four to six months leading up to the race. Peloton’s marathon training program, for example, is 18 weeks long. “How much time you need to train fluctuates based on how your body responds to the training,” Shah says. 

  • Elite Runners: 3 Months. While less experienced runners typically need more time to prep their bodies, pros who are used to high mileage can pull off a marathon with a shorter buildup of around 12 weeks, or three months. 

When Should You Start Marathon Training?

If you’re training for a marathon, you’ll probably want to begin dedicated marathon training three to six months before race day. For a fall marathon, that could mean starting anytime between March and August, depending on the timing of your race and how long you want to train. For a spring marathon, you’d need to start sometime between September and February. 

If you don’t give yourself enough time to train, you might not run as well as you could on race day, or you may not have enough time to safely build up your mileage. On the other hand, if you stay in intense marathon training mode all year long, you’re setting yourself up for overtraining

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What a Marathon Training Plan Typically Looks Like

Marathon training plans can vary based on your fitness level, goals, and how much time you have to dedicate to running. But most solid plans—including Peloton’s 18-week Road to Your 26.2 program—follow the same basic structure: 

  • A week will typically consist of: 2–3 easy runs, 1–2 speed runs (like interval workouts or tempo runs), plus one long run. 

  • Mileage will slowly build over the weeks until you’re ready to tackle your longest long run. Peloton’s plan, like most marathon programs, peaks at a 20-mile long run. 

  • Then, you’ll taper that mileage back for about three weeks so your legs are fresh for race day. 

Common Types of Runs In a Marathon Training Plan

Each run you do during marathon training has a specific purpose. “Runners need to understand their body, their strength, their limitations, and work on those specifics,” Shah says. That said, most marathon training programs (including Peloton’s) include these four types of running workouts.

Long Run

The weekly long run is just what it sounds like: the run with the highest mileage each week. It gradually builds throughout training to get your legs and lungs ready to tackle the marathon distance, and typically peaks at about 20 miles. “Endurance is the key—the long run is the most important,” Becs says. 

Tempo Run

Although there’s some debate on the exact definition of a tempo run, the general idea is to hold a fairly difficult pace for a sustained period of time. Most experts suggest aiming for a comfortably hard effort (about a 6 out of 10 RPE, or rate of perceived exertion), or the top speed you could run for an hour straight. These workouts are tough, but they help prep your body (and mind) to maintain the pace you want on race day.

Recovery Run

Recovery runs are sometimes called easy runs because they’re fairly short and done at a slower pace. They help your body bounce back from harder runs faster by getting your blood flowing without putting a ton of stress on your muscles. They also get you ready for what you’ll feel in the later miles of a marathon. “Always do recovery runs to capture your power of running on fatigued legs, which is what endurance running is based on,” Becs says. 

Interval Run

Interval training is a type of speed work that asks runners to hit specific intensities for certain amounts of time before they rest and repeat. That might look like 60 seconds at a 5K pace repeated 10 times with 30 seconds of rest in between, or hitting half marathon pace for one mile and repeating that three or four times. This not only helps increase your speed but also builds mental toughness that will make marathon pace feel more doable on race day. While there are different types of interval runs, common workouts include sprint workouts.

Cross Training for a Marathon

When it comes to cross training during a marathon build-up, Shah recommends focusing on building strength, power, control, and stability. “Those are the four most important components that you need to be thinking about,” she says. Strength can be built through traditional strength training exercises like lunges and deadlifts. To build power, plyometrics are your best bet. And workouts like yoga and Pilates can increase your control and stability. In any of these workouts, Shah suggests focusing on the quads, hamstrings, glutes, calves, and core—the muscles that are most challenged in distance running. (For more guidance, check out this guide to strength work during marathon training.)

“Ideally, you want to incorporate strength training a couple of times a week and as the intensity of the running program increases, the intensity of the strength sessions will decrease, meaning you will lift lighter,” Becs says. “The same applies to other modalities of cross-training such as cycling or rowing: You decrease the intensity of those as you close in on marathon day.” 

Nutrition for Marathon Training 

When you start racking up serious miles, your diet needs to step up, too. In particular, make sure you’re getting enough carbohydrates and protein, says registered dietitian Danielle Crumble Smith. “There's a heavy focus on carbohydrates because that helps with glycogen stores, which is essential,” she says. “But if you’re not consuming adequate protein, then you might end up feeling really tired and not recovering well, breaking down muscle.”

Pre-Run Nutrition

Before your runs, stick with simple, easy-to-digest carbohydrates and maybe a bit of protein. “Those simple carbohydrates break down to sugar more quickly, which is really beneficial during a long run because you want your body to be able to access that glycogen,” Smith says. Meanwhile, having a little protein will help maintain your energy levels longer. That could look like a bagel with some peanut butter and a banana, maybe with a hard-boiled egg or a little Greek yogurt. (Avoid anything high in fiber or fat, both of which can take a while to get through your system.) 

Long Run Fueling

On long runs, it’s also important to eat while you’re running. Most runners need 30 and 60 grams of carbohydrates every 30 to 45 minutes to sustain their energy—that can be accomplished by taking gels, sipping sports drinks, or even eating pretzels or sugary candy. Smith suggests using your weekly long runs to experiment with different kinds of fuel to see how your body responds, well before race day arrives. It can sometimes be hard to take in enough calories without causing GI issues (hello, runner’s stomach), but it is possible to train your stomach to digest while running just like you’re training your legs.

Post-Run Recovery Fuel

You’ll want to eat more protein and carbs again after your run to refuel. “Have an omelet with avocado toast or a sweet potato hash that has eggs,” Smith suggests. Running long distances can sometimes repress our hunger signals, so if your body doesn’t feel ready to eat right away, Smith suggests drinking a protein shake instead. 

Pre-Race Carb Loading

During the three days before the race, you’ll want to focus on carb loading. For each meal, “have half of your plate carbohydrates, with a quarter of protein and a quarter of veggies,” Smith suggests. Just make sure the veggies are easier-to-digest options like green beans and zucchini rather than kale or broccoli, so you can hopefully avoid porta-potty stops during the race. 

Woman drinking water out of a hydration vest while on a Peloton marathon training plan run.

How to Set a Realistic Marathon Goal

When you’re running your first marathon, most running coaches say the best goal is simply to cross the finish line, without any pressure to hit a certain time. That’s still a great plan even if you’ve run a dozen marathons and just want to get out there to enjoy the course. 

If you do want to set a time goal, you can base it on how you’ve performed in previous marathons, taking into account your current fitness level and additional factors such as your upcoming race’s elevation profile and average weather forecast. You can also run a half marathon near the peak of your training, then plug your finish time into an online race predictor to get an estimate of how you’ll do over 26.2 miles. 

Note: Many running coaches recommend setting three goals: an “A” goal for if everything goes right on race day with ideal temps and no unexpected challenges like cramps or GI distress, a “B” goal that’s a little less of a reach, and a “C” goal that you’ll still be proud to accomplish if the first two don’t end up being possible on race day.

Can You Train for a Marathon on a Treadmill? 

Yes, you can train for a marathon on a treadmill—though you should aim to do at least some of your training runs outside. Marathon training on a treadmill like the Peloton Tread or Tread+ offers a lot of perks. For one, you can control your running environment, which means it’s a safe place to run when the weather isn’t cooperating or you don’t feel comfortable running alone outside. It also means you can have precise control over the pace, Shah points out. “A treadmill allows you to train specific parameters,” she says. This makes it especially helpful for speed work like interval workouts or tempo runs when you want to nail a particular pace.  

“You can do as much training on the treadmill as you need to or want to,” Becs says. That said, your marathon will most likely take place outside, so you should get used to running on a similar surface—whether that’s on asphalt or dirt trails. “Ideally, long runs are done outside,” Becs says, “but sporadically doing them on the tread is better than not doing them!” 

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What to Do When Marathon Training Gets Hard

Marathon training can be… a lot. When you’re tempted to throw in the towel, remember: “Everything passes,” Becs says. Each hard interval and each long run will eventually end. Even your whole marathon training plan will finish on race day, and you can let your legs recover afterward for as long as they need. 

In the meantime, keep in mind that you signed up for a marathon not because it’s easy, but because you wanted to challenge yourself. As Becs says, “Hard things change us and we only get tougher by getting through them.”

The truth is that struggling during marathon training means you’re doing exactly what you should be doing to get stronger and faster. So don’t be too hard on yourself. “Be humble and have grace,” Becs says.

That said, if you suspect you’re running more than your body can handle, it might be time to pull back a bit or amp up your recovery efforts. Shah suggests paying attention to your VO2 max stats if you have a smartwatch (it won’t give you an exact measurement, but it can give you a general idea). This number tells you the maximum amount of oxygen your body can consume during exercise. “When your VO2 max starts depleting, that could mean you’re overtraining,” she says. 

When Should You Start Tapering Before a Marathon? 

As you get close to race day, it’s time for what’s called a “taper.” During marathon training, a taper is the point where you progressively dial back your training just before your race so that your body has time to recover from all the fatigue you’ve built up over the past several weeks. 

“This period gives the body time to soak in all the hard work and adaptations it’s made in training to arrive at the start line as strong as possible,” Becs says. Research published in Frontiers in Sports and Active Living shows that the ideal taper lasts three weeks—runners who tapered that long finished an average of five minutes and 32 seconds faster than those who followed a shorter taper. 

During this time, you’ll decrease your volume, or how many miles you’re running. You’ll want to keep doing your interval and tempo runs to keep your legs snappy, but be careful not to overdo the paces since you’ll be feeling fresher. Also, now that you aren’t running so much, you can use the extra time to focus on recovery techniques like stretching, foam rolling, and Epsom salt baths.

How to Recover After Running a Marathon

Although you might be tempted to simply collapse on the couch for a week after a 26.2-mile race, your body will feel a whole lot better if you take a more strategic approach to marathon recovery

For starters, go ahead and let yourself get lots of sleep: Embrace the naps and nine-hour nights in bed that your body is craving. But keep moving a bit during the days after your race with some gentle, low-impact activities like walking or cycling as well as mobility work. (Most coaches recommend giving yourself at least a week off from running before you start doing any easy jogs again.)

Also make sure you’re refueling your body with plenty of complex carbs and lean protein, plus antioxidant-rich fruits and veggies—and rehydrating with plenty of fluids. You may no longer be actively training for a marathon, but recovery takes work, and you want to give your body the tools it needs to do it well. 

Training for a Marathon with Peloton

Ready to get started? Peloton has you covered with an 18-week marathon training plan, Road to Your 26.2, available on the Peloton App. The guided audio-only runs start at just two to three miles and build up to 20 to get you ready for race day. You’ll get dedicated marathon race prep runs, tempo runs, recovery runs, long runs, and strength classes designed specifically to meet the needs of runners. All the while, the app will track your progress so you can see just how close you’re getting to that finish line.

This content is for informational and educational purposes only and does not constitute individualized advice. It is not intended to replace professional medical evaluation, diagnosis, or treatment. Seek the advice of your physician for questions you may have regarding your health or a medical condition. If you are having a medical emergency, call your physician or 911 immediately.

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Headshot of Peloton instructor Becs Gentry. She's wearing a light blue Peloton two-piece workout outfit and smiling with her arms crossed.

Featured Peloton Instructor

Becs Gentry

Becs joins Peloton from London as an accomplished distance runner and coach who uses the sport as a way to explore the world. You’ll leave her class smiling and proud.

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