Watching runners zip by in their marathon gear and seeing posts about triumphant race finishes can make even non-runners interested in running their first marathon. But training for a 26.2-mile race isn’t something you can just jump into. How long do you need to train for a marathon, and what actually goes into marathon training?

As a certified running coach for 12 years and someone who’s run several marathons myself, I can say that training for a marathon takes a lot of work (and sweat and snacks) but it can be well worth the journey. To learn more about how to decide if you are ready, how long to train for a marathon, and what to expect from the whole process, I spoke with Jonathan Poston, a USATF certified level II endurance coach and the founder of Running Coach Pro.

What is a realistic timeline for marathon training?

How long you need to train for a marathon largely depends on how big of a running base you’re starting with. “Running a marathon is not just about putting one foot in front of the other for 26.2 miles. It involves careful planning, dedication, and a structured training regimen,” explains Poston. “The timeline for marathon training varies greatly based on an individual’s fitness level and prior running experience.”

“Running a marathon is not just about putting one foot in front of the other for 26.2 miles. It involves careful planning, dedication, and a structured training regimen.” —Jonathan Poston

Poston provides some general guidelines:

• Beginner (0-1 years of running experience): Typically, a novice runner should plan for at least four to six months of training to build the necessary endurance and confidence.
• Intermediate (1-3 years of running experience): An intermediate runner may need three to five months, depending on their existing fitness level and how much they’ve been running regularly.
• Advanced (3-plus years of running experience): More experienced runners might require two to four months, as they likely have a solid fitness base and a better understanding of their bodies.

What kind of base should you have before you sign up for a marathon?

Poston says that there are medical clearances that a physician can do to physically make sure that you are able to train for a marathon. But there are no firm “rules” about how much someone should be running every week before attempting marathon training. This is largely because each individual is unique and what may be physically reasonable for one person in terms of training for a marathon may not be safe for someone else.

That said, Poston shares some general guidelines: “Marathons are advanced-level running events and really should not be attempted by runners who aren’t already running 20 to 35 miles per week, with some sort of long run mixed in every seven to 14 days (at least 10 miles),” advises Poston. “Even then, it can still take a seasoned runner 10, 15, or 20 weeks or so to increase their training in order to gear up for a marathon event.”

If you aren’t yet running that much, yet want to take on the challenge of becoming a marathon runner, the key is to slowly build up your mileage. Poston shares that a common suggestion is to add no more than 10 percent a week so you don’t get injured. For example, if you’re currently running 10 miles a week, add just one mile to start with. Keep building gradually this way until you hit 20 to 35 miles per week, and get up to a 10-mile long run. Then you’re ready to start a structured beginner marathon training program.

Even if you have a decent aerobic base and have been running consistently, keep in mind that training for a marathon safely will still take time.

“It may be said that a runner is ready to embark on training for a marathon when that person is already able to run 20 to 35 miles per week, complete a 10 miler without a problem, and is psychologically prepared to take the training to a level of intensity that can tempt even seasoned runners to outright quit,” says Poston. “Even at this very decision point, first-timers still have 20 weeks of grueling training ahead of them, and the event itself looms large psychologically as a make-or-break challenge.”

How many hours and runs per week should you expect when marathon training?

Poston explains that the number of hours per week that you will need to train and the number of runs per week will slowly increase over the first several weeks of a marathon training program, and then taper down in the two weeks or so before the race to allow your body to rest and recover.

At the peak of the plan, you might be looking at 40 to 50 miles per week, which might mean about 10 hours of running (or much more, if you’re going at a slower pace). However, some beginner marathon training plans might be more conservative than this to keep new runners healthy. “For many runners, adding distance or time means increased chances of injury and an additional time commitment that can cause stress in other areas of life,” says Poston. Make sure you’re prepared for both the physical and logistical toll marathon training can take.

What does a marathon training plan involve?

There are a few types of runs you will find on a marathon training plan:

• Long runs: Expect to do one long run every week that generally increases in length over the course of a training plan. Most plans have you peak at 20 to 22 miles, which you’ll do once or twice before the race. Then, in the last couple of weeks before the marathon, the distance of the long run will scale back down so that you are more rested come race day. Use all of these long runs as dress rehearsals to practice what you’re going to wear and eat during the race.
• Easy/recovery runs: These slow, shorter runs allow your body to recover while building resilience and cardio fitness. Most marathon training plans include two to four easy runs per week.
• Speed work: Faster intervals or tempo runs will improve your pace and build strength. These are usually done once or twice a week as a dedicated workout, or you might build in marathon goal–pace miles into your long run. Before these workouts, you want to make sure to warm up properly.
• Rest days: Yes, taking time to recover is essential for injury prevention. It’s also when you reap the benefits of your hard work and your muscles grow stronger. Poston says most marathon programs will offer one to three rest days per week.
• Cross-training: Activities like cycling, swimming, strength training, or yoga will supplement your running. These types of workouts reduce the risk of injuries by decreasing the impact stress on your body. Most coaches recommend one to two cross-training sessions per week, but they can be short (just 20 minutes can do the trick).

Poston says most training schedules will tell you exactly how many miles or minutes to run per day and what type of pace or intensity for the run should be. “Sometimes, it is general, like ‘easy run,’ and speed workouts may be specific, like ‘10 percent faster than race pace for x number of miles.’”

Avoid these 5 common beginner marathon training mistakes

Pumped up and ready to get started? Poston warns of a few common mistakes he sees runners make when they’re training for their first marathon, which could lead to injuries that keep you from making it to the start line.

1. Don’t do too much, too soon

Overtraining can lead to injuries. It is important to gradually increase your mileage and intensity, even if you feel “good” or like you can do a lot more.

2. Don’t skip rest days

Runners sometimes skip rest days to speed through training or make up for lost time. Or, they might get so addicted to running that they don’t want to take a day off. But Poston says that rest days are crucial for recovery.

3. Don’t forget about nutrition

According to Poston, “Failing to fuel and hydrate properly during training can hinder progress, which is why any good marathon training program includes nutrition training as well.”

4. Don’t put off cross-training

“It is true that to become a good runner, it is important to mostly run, but not only run! Strength training, stretching to maintain a normal range of motion, and cross-training on a bike instead of a run once a week or so is a way to mix it up,” says Poston. “It helps prevent overuse injuries and maintains overall fitness.”

5. Don’t ignore pain

Poston says it is essential to listen to your body, not run through pain, and seek help for any persistent injuries. Remember: The goal is not just to make it to the finish line, but to get there healthy!