How Far Is Too Far for a Long Run During Marathon Training?

Jump to:

• What to Know About the 3-Hour Long-Run Rule
• 4 Coach-Approved Ways to Approach Peak Long Run Distance
• Factors to Consider for Determining Your Longest Long Run
• How to Know You’re Running the Right Distance for You

An aspect of marathon training that’s undebatable: tackling long runs. But the question of how far your longest training run should be lingers in the minds of many marathoners, and it turns out the answer isn’t so simple.

Your longest long run prepares you mentally and physically for the level of fatigue you’re going to experience on race day, and it’s the closest you’ll get to simulating the demands of the marathon, Greg McMillan, exercise physiologist and USATF-certified run coach tells Runner’s World. “This makes the longest long run particularly important for marathon training, as it helps you experience and prepare for that unique type of whole-body fatigue that’s difficult to replicate in other training sessions,” he says.

You’ll typically run your longest long run during peak week, or about one month out from race day, but how far you should go sparks a little controversy. For starters, some coaches say that even though your marathon may take you longer than three hours to complete, your peak-week long run shouldn’t exceed that time.

“Runners really like rules, like the three-hour long-run rule, but that rule is not really based on any hard science,” says Laura Norris, owner and coach at How to Break 4 Hours in the Marathon in Boulder, Colorado. “A lot of the time, the study that people cite actually comes from a study on rats in the 1980s—not done on humans, not done on marathon training,” she says.

Journal of Science and Medicine in Sport study she has often seen cited on social media. It was published in 1982 in the Journal of Applied Physiology, and suggests that rats that exercised for 90 minutes saw a plateau in adaptations, compared to those that exercised for 60 minutes—but nowhere does it mention the diminishing return for three hours in humans. “Sometimes it seems like people cite this study because they’ve seen it cited before in this conversation, without actually reading it,” says Norris.

Still, run coaches say there’s not necessarily an ideal distance for everyone’s long run. “I have not seen any scientific evidence that there’s a perfect amount of time or distance for the long run,” Randy Accetta, Races - Places Road Runners Club of America tells Runner’s World.

Rather, to determine how far you should go for your longest long run during marathon training, you have to examine personal factors, like your speed, goals, fitness level, injuries, and total volume.

To help you pinpoint the ideal distance for you, we spoke with experts to find out what they think about the three-hour rule and answer the question: How far is too far for a long run? And how far is just far enough? Whether this is your first marathon or your 15th, here’s how to determine how far to go during peak week.

What to Know About the 3-Hour Long-Run Rule

While the above mentioned study gets called out in conversations about the three-hour rule, some coaches have also set limits on the duration of long runs. “The rule also evolved from Daniels’ Running Formula [by legendary coach, Jack Daniels], which suggests that 2.5 hours is the point where diminishing physiological returns set in and injury risk increases,” says Norris.

Over the years, other coaches have promoted similar training philosophies, including How to Tackle the Long Run, which has marathon runners topping out at 16 miles for their longest long run before tackling 26.2. That’s likely another reason this approach became more popular throughout the running community.

But its worth recognizing that this rule was made by coaches who started out by primarily working with athletes who run marathons in about three hours or less, Norris explains, so it may fall short of considering runners who take longer to finish 26.2 miles.

Although there are no studies done directly on a three-hour long-run rule, some recent research challenges the rule by examining the effects of peak long run mileage on marathon finish times.

For example, a 2020 systematic review and meta-analysis published in the Journal of Science and Medicine in Sport examined 85 studies on marathon performance and found that 32K long runs (just under 20 miles)—along with weekly training volume—were “significantly associated” with faster marathon finishing times. Putting that into perspective in terms of timing, it would take anyone who runs slower than a 9-minute mile more than three hours to complete 20 miles.

This study also reinforces the idea of keeping in mind weekly mileage—not just long runs—when marathon training.

4 Coach-Approved Ways to Approach Peak Long Run Distance

There are many ways to successfully train for a marathon and what works for one runner might not work for the next. Here’s a breakdown of different methods for how far to go on your longest long run of marathon training, according to some top running coaches’ philosophies:

• How to Tackle the Long Run caps the longest marathon training run at 16 miles yet covers more than 50 miles per week, across six days, in order to build the fatigue resistance you need for marathon day. A 16-mile long run will take you just under two hours at 7-minute pace, and more than three hours at a 12-minute pace, so it’s a reasonable range of time spent on your feet, no matter your speed.
• Jeff Galloway’s training method is geared toward those who want to use the run/walk method for a marathon. You run three to four days a week, with a full 26-mile long run to emphasize physical and mental endurance. Because the walk intervals offer recovery midrun, Galloway says you can go farther and therefore conquer 26 miles ahead of race day.
• Jack Daniels supports capping your peak long run at three hours—no matter the distance—to avoid overtraining.
• Greg McMillan’s training plans may have you run more than four hours, because it uses Everything to Know about Hammer Interval Training to cater to any fitness level. For example, McMillan suggests your longest long run equates to at least the duration of your Everything to Know about Hammer Interval Training, Guide to Pro Runner Form:
  
  • If you’re aiming to finish the marathon in about 3 hours: Run at least 3 hours, up to 3 hours and 45 minutes
    
  • If you’re aiming to finish the marathon in about 4 hours: Run at least 3.5 hours, up to 4.5 hours
    
  • If you’re aiming to run the marathon in five hours or more: Run at least 4 hours, up to 4.5 hours

McMillan explains that this method adequately addresses the physiological training benefits and the psychological benefits of doing your longest long run, while still remaining flexible and applicable to runners of all speeds.

According to Runner’s World training plans, your longest long run during marathon training will typically range from 20 to 22 miles during your peak week, which falls about a month out from race day. (All plans focus on mileage, rather than minutes, so how long that takes you will depend on pace.) You’ll run at least four days a week.

A general rule of thumb is to keep your long run distance at about 25 percent of your total weekly mileage, Accetta adds.

maintaining your base
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Factors to Consider for Determining Your Longest Long Run

While there are general guidelines to follow and many different coaching methods to consider, you can personalize your long run approach by considering your pace, experience level, and goals.

Pace

to recover well, reduce volume, and maintain long run pace should be about 90 seconds to two minutes slower than your goal race pace, meaning you won’t cover the same distance you would when running at marathon pace. For example, if you’re looking to or running on, you might run your 22-mile peak long run at a 10:50 per mile pace, which will take you just under four hours to complete.

Tips for Tackling Marathon Training’s Peak Week on your feet in accordance with your pace. “Someone who runs their easy pace at 11:30-minute mile pace versus 8:30-minute mile pace is going to be out there for about an hour more [for distances like 18-milers],” Brian Rosetti, certified run coach and founder of the Run SMART Project and V.O2, tells Runner’s World. “That’s a lot more stress on the body, a lot more repetitive stress, and you’re burning a lot more energy.”

In general, the faster your pace, the less you have to worry about the three-hour rule. Conversely, if you’re using the run/walk method and average a slower pace, you also don’t have to worry about the three-hour rule.

With run/walk, you can recover better throughout the duration of your long run, because you’re taking slower strides between efforts, as opposed to running straight through, explains Norris.

Experience Level

If you’re a beginner…

Norris explains that for newbies—those running a marathon for the first time—capping your long run at about three hours might make sense. “A long run of any distance is a brand new stress on the body, and it’s going to take them a lot more time to recover from than an experienced marathoner,” she says. “They just aren’t used to being out there that long, and it’s such a higher stress on their bodies than it is for this experienced runner who’s been out there several times.”

However, McMillan argues that newer runners may need to spend four to five hours on their feet—particularly if they expect to be out on the course for longer than that—to prepare for the mental and physical stress of their marathon.

Whatever you decide is right for you, stick to a training plan DOWNLOAD BREAK 5 PLAN time or mileage. And if you do decide to run a 20-something-mile long run during your peak week as a beginner, maintain a true conversational easy pace, give yourself rest breaks when you need to, and make sure you have at least three weeks of your taper mile long runs you have listed on the schedule, and how your body can handle that stress intensity, Accetta suggests.

If you’re an experienced runner…

Norris defines an experienced runner, as someone who has trained for and completed at least two marathons before without facing injury or burnout, and starting to think about progressing your training, like aiming for higher mileages or a faster time goal.

As an experienced marathoner or a high mileage athlete, you don’t need to spend as much time building up with long runs, explains Rosetti, because you’ve likely adapted to marathon training before.

If you’ve run a recent marathon, like in the past year, you can probably get away with peaking with a shorter long run, particularly if you’ve been maintaining your base, Accetta agrees. “I’d think that if someone is running 40 to 50 miles a week with a long run of 15 to 17 [miles] on a regular basis, then they don’t necessarily need to do a longer long run,” because the consistency can carry you through the difficulties of race day, he explains.

On the other hand, if you’re experienced and you run closer to a five-hour marathon or longer, you might be able to handle more time on your feet. “Even if a 18- to 20-mile long run takes them 3.5 to four hours, their musculoskeletal systems are more adapted to it, because they’ve done marathons before. They’ve done races that put them on their feet for five to six hours, and they don’t need as much recovery,” says Norris.

Finally, if you’re an experienced runner and you run a faster marathon—say, around three hours—or you’re training to compete, you might opt to do a longer long run during peak week to progress in your training ability.

“A lot of the time those athletes, they want to PR, they have big goals. They want to improve. They’re not just focused on completing the marathon because they’ve done that already,” says Norris. “While they could do a 16- or 17- mile long run, they might choose to do a 22-mile long run to make sure they don’t slow down in the final half because they want to PR.”

How to Know You’re Running the Right Distance for You

Keep these tips in mind to get the most out of your marathon training experience without overdoing it.

1. Listen to Your Body

If you’re training for your first marathon, you can likely gain a sense for how prepared you are to run your longest long run by the time peak week approaches. If you’ve completed your previous long runs without pain or injury, and you feel good about your adaptations, chances are you’re ready to take on that peak long run.

On the other hand, if you’re showing signs of overtraining syndrome, like fatigue, aches, and a higher heart rate, you’re not recovering between workouts, or your form is breaking down on runs consistently, then that might be a sign that you need to dial it back and go for a shorter peak week long run. While it could be that you’re taking on too much mileage or spending too much time on your feet, overtraining can also come from prepares you mentally and physically for the level of like fatigue, aches, and a higher.

2. Trust the Training Plan

You want to give your body time to adapt to training, so you’ll often find marathon training plans that increase your long run distance every other week—rather than a weekly basis. “You really have to respect the distance and the amount of repetitive stress on the body, especially in the middle of marathon training. You want to give yourself a little buffer to allow yourself to adjust, and then you can take a bigger jump,” says Rosetti.

Coach-Approved Ways to Approach Peak Long Run Distance endurance gains with long runs that include race pace or tempo work to help you hold your goal pace for longer. For example, the Runner’s World or running on plan time or mileage.

3. Keep Frequency in Mind

Once you’ve weighed all the factors and picked a training plan, it’s important to also pay attention to how many 20-mile long runs you have listed on the schedule, and how your body can handle that stress.

“You have to be very careful about how many long long runs you add in,” explains Rosetti. He explains that some runners might do three 20-mile long runs in their marathon build-up to practice fueling or running on tired legs, while others might only do one to have time to recover more. Go back to listening to your body to assess what’s right for you.