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Ah, the marathon. It’s one of those big bucket list items that so many people are itching to cross off. But with so many plans out there of varying lengths, it can be hard to know how long you need to carve out to get to both the start and finish lines healthy and happy.
First, note that “there is no one way to train for a marathon,” says Amanda Nurse, a certified running coach, founder of Wellness in Motion Run Coaching in Boston and a two-time Olympic Trials qualifier in the marathon. Some people, she says, do it with more miles under their feet, while others can have a great race doing a decent amount of cross-training and by building a great cardio base in other ways. “It is so individual,” she adds.
One thing all experts will agree on, though, is you do need to have a plan—and most plans will say it takes about 16 to 20 weeks to train for a marathon.
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“Following a plan is beneficial to improve not only your physical fitness—aerobic capacity, lactate threshold, and strength, but also your mental fitness—motivation, discipline, and consistency,” says Raj Hathiramani, a RRCA-, USATF-, and USA Triathlon-certified coach, as well as a running coach at Mile High Run Club in New York City.
Here, experts weigh in on why it’s important to take 16 to 20 weeks to train for a marathon, and what the training block can do for you and your body.
What happens to your body during marathon training?
Yes, the training period is meant to give you enough time to properly increase your mileage to help ensure you are fully prepared for 26.2 on race day. But, according to Alex Rothstein, M.S., C.S.C.S., coordinator and instructor for the exercise science program at New York Institute of Technology, there are tons of adaptations occurring during this time that are a direct result of each training session. And you need these changes to occur to be ready come race day.
For starters, the heart gets stronger, increasing the force at which it can pump blood throughout the body. It also becomes better at refilling, allowing more blood to be pumped each time it beats. The blood vessels become better at distributing the blood throughout the working muscles, too, while the blood also becomes more capable of carrying oxygen. This improves your cardio function and aerobic capacity.
A bonus for first-time marathoners: You’ll experience a “reduction in central blood pressure and aortic stiffness that’s equivalent to a four-year reduction in vascular age,” according to a study in the Journal of the American College of Cardiology, regardless of your actual age. Translation: You gain healthier blood vessels.
Meanwhile, your muscles—particularly type I, slow-twitch endurance fibers—have a small increase in size, which up their ability to generate force, making them more efficient at submaximal intensities (like long runs). This also increases their ability to store glucose/glycogen, which you’ll need for fuel and energy on race day.
Mitochondrial density in the muscles also increases, as well as aerobic enzyme activity—both play a role in increasing an individual’s oxygen-consuming capacity. These together also make you more aerobically efficient, so those long miles start to feel easier.
What’s more: The body’s supporting structures (think tendons, ligaments, joints, muscles) also become stronger, which means you develop more tolerance to the overall impact of running, so that any single bout of running is more manageable. Not only that, but a study in the Journal of Applied Physiology found that runners with high mileage experienced adaptations that included muscles not having to work as hard due to a more efficient use of the tendons.
“It is the culmination of all of these adaptations from your training cycle that ultimately result in a successful performance,” says Rothstein, who also notes your economy of effort (as we run, we get better at running efficiently) also improves. Failure to put in the proper amount of time training and you’ll likely have a poor race because “without the proper development of supporting structures and energy systems, the body will struggle tremendously to meet the energy demands placed on it during a long-distance race like a marathon, and an individual will have the miserable experience of hitting the wall,” he adds.
Even worse, if you don’t take the time to train for a marathon, you are setting yourself up for injury because “your body simply won’t be adapted to the amount of repetitive impact you place it under,” Rothstein says.
To gain these adaptations, how long does it take to train for a marathon?
Honestly, the answer depends, because so many adaptations occur at one time, Rothstein says. You begin improving after just one exercise session, but he says aerobic adaptation occurs over months.
Generally speaking, though, it takes those 16 to 20 weeks mentioned earlier to train for a marathon and for these fitness adaptations to occur.
With a standard 16- to 20-week marathon training plan, “you can ensure you build your training volume wisely and gradually over a significant period of time,” explains Jess Movold, Runner’s World running coach, though she notes that if you’re willing to put in the work for 16 weeks, even if you’re a beginner, that should give you enough time to start and finish 26.2. “Taking enough time to properly train will help fully prepare you for race day, but it will also decrease your chance of getting injured during your training, which often happens when runners increase their intensity too quickly.”
Research in the British Journal of Sports Medicine backs this up, revealing that of the 735 runners who were monitored during the 16 weeks leading up to the New York City Marathon, those who avoided ramping up their weekly mileage too quickly were less likely to become injured, whether they were newbies or experienced marathoners.
Plus, it can be helpful to have more flexible and longer training cycles, says Hathiramani, to account for life—work travel, personal conflicts, or medical conditions—getting in the way.
Of course, there will be some runners who succeed using slightly more or less time than 16 to 20 weeks. Hathiramani and Nurse agree that for active runners with race experience, 12 weeks might be enough to train for a marathon.
“Your age and current level of fitness, weekly mileage, race experience, injuries or conditions, and life schedule are all factors to consider when deciding how long your training cycle should be,” says Hathiramani. “A training plan less than 16 weeks is often tailored for runners who have marathon experience and/or a higher mileage base, while those beyond 20 weeks can become mentally and physically exhausting and lead to overtraining, unless you are truly starting from scratch.” If you are going from couch to 26.2, then you might require longer than those 20 weeks to train for a marathon.
For a complete beginner, Rothstein recommends starting a bit slower and adding at least one- to two months-worth of training to a 16- to 20-week training plan. “This would mostly be for the purpose of reducing injury risk since most beginner’s bodies will not be able to keep up with the initial training load, let alone the total accumulation of miles over a consistent 16- to 20-week plan,” he says.
Regardless of the time you take to train, Rothstein advises that you stay vigilant. “Constant soreness, fatigue, nagging aches, or injuries are clear signs that you are at risk of overtraining and 16 to 20 weeks may not be enough time for you to complete a training program,” he says.
How long does it take to train for a marathon if you don’t really run?
As mentioned, if you’re going from couch to 26.2, you probably need more than 20 weeks to train for a marathon. And that’s because you need to have a running base before you jump into marathon training.
Basically a running base is a time period of about six to 12 weeks before you officially begin training that gives you a solid foundation or “base” from which to progress. It’s important to keep in mind, just as with training itself, that “everyone is different and some runners adapt faster than others depending on overall health, wellness, and strength,” says Movold. “Some people need a full year to connect to a healthier lifestyle and to gain a better grasp of fitness before tackling the challenge of marathon training. Other people might have an already existing relationship with fitness with a base of strength allowing them to transition into marathon training sooner.”
If you are still new to running, want to train, and feel ready for a challenge, Movold advises having a base of at least three to four months of easy runs, three to four times a week, aiming for 15 to 25 miles weekly. Miles aside, “the most important thing for someone to jump into marathon training is the strong desire to want to do the marathon and the work it takes to be ready for race day,” she says.
“If you are able to run, I truly believe anyone can jump into marathon training, but the training plan would depend on the runner’s background, fitness, conditions, and goals,” adds Hathiramani. “All runners should focus on building a base unless they have run a recent half or full marathon, but the base would also depend on the person’s recent mileage, which can range from 0 to 50+ miles.”
For Nurse, training is meant to help you be comfortable and confident at the starting line. She says that if you can jog 20 miles, you can make it to the finish line. That’s why she suggests her clients do a little back tracking to help determine the length of training needed to get to that peak distance.
Remember: You will only increase your miles by one or two each week (never increase weekly mileage by more than 20 percent, but keep it closer to 10 percent) and every fourth week plan a down week, which is when you reduce your mileage by about four to six miles from your previous long-run distance to give the body a break. For example, if you run 12 miles, 14, miles, and then 16 miles, your next run should be between 10 to 12 miles. Armed with this information, you can approximate how many weeks it will take to build up.
How long does it take to train for a marathon if you have a time goal?
If you are going for a specific time in your marathon, a key indicator for how long it will take to train can be how fast you run shorter races. For example, race a half marathon or 10K to determine if you are within the general range for being able to hit your goal, advises Nurse. “If you run a 1:56 half marathon, with a good training cycle, you should be able to run a sub 4-hour marathon,” she says.
A 16- to 20-week training plan should help you achieve your time goals, as long as you set realistic expectations. If you’re already an experienced runner and close to that time goal, you may even be able to do a shorter plan.
When goal setting, just remember “it’s best to have A, B, and C goals depending on how your cycle goes,” adds Nurse, “with C being very tangible and attainable, and A, a stretch, but a good one if training goes well.”
With so much to consider, Nurse suggests recruiting a running coach. “A coach can help fine tune things for you so that can run the best you possibly can given your circumstance,” she says. They also can be a source of motivation, as well as reassurance when you’re struggling with a workout, miss a run on your training plan, or have general questions about training.
Ultimately, training for a marathon involves a lot of trial and error. “Every runner is so different, and you’re going to learn what works best for you,” says Nurse. The key points: Listening to your body and recognize that everyone’s path to the marathon takes different turns. So follow what works for you.
What does training for a marathon look like?
Once you’re in the thick of marathon training, your actual plan will be a mixture of everything from easy runs (a comfortable and controlled low-intensity effort), to tempo runs (a sustained, faster-than-usual effort that builds speed endurance), to speedwork (short, fast, interval-based runs), to long runs (incrementally longer runs to increase maximum mileage).
You’ll also have built in recovery weeks, typically a drop in mileage every fourth week, says Nurse. This will “allow your body to reap the benefits of all that hard work without allowing your body to burn out or even to have that mental fatigue from training if you’re constantly just ramping up for four months or more,” she says.
A two- to three-week taper will also be a part of that 16- to 20-week window to help you wind down your training. According to a review of studies in Medicine & Science in Sports & Exercise the taper period is linked to beneficial physiological, psychological, and performance adaptations. All of these workouts and techniques—active runs, recovery runs, and tapering—pay off in getting you through 26.2 miles healthy and confident.
Rozalynn S Frazier is an award-winning, multimedia journalist, and certified personal trainer living in New York City. She has created content for SELF, Health, Essence, Runner's World, Money, Reebok, Livestrong, and others.
