Basing Your Weekly Mileage on Your Race Distance? One Coach Explains Why That’s the Wrong Tactic—and the Real Factors to Consider.
If you’ve ever wondered whether you’re logging enough miles for your goal race, you’re probably asking the wrong question. Whether you’re training for a 5K, 10K, half or full marathon, three important training factors determine your weekly mileage—and they have nothing to do with your race distance.
It might seem like moving from a marathon to a 5K automatically calls for lower mileage, but that’s not always the case. “Everyone thinks training for a 5K means you’re not running a lot, but realize even professional 1500-meter runners are running 70 to 90 miles a week,” says Danielle Hirt, RRCA-certified run coach and founder of Run With Coach D. “So your race distance doesn’t always determine your total weekly mileage.”
While marathon training requires enough volume to prepare for race day, that’s an exception, not the rule. Hirt breaks down why your race distance doesn’t matter as much as you think it does when it comes to mileage, and the three key factors you should really consider.
3 Factors That Determine Your Weekly Mileage
1. Training Age
The biggest factor that determines your weekly mileage: your training age, says Hirt, or how long you’ve been running.
Your training age takes into account how long you’ve been aerobically active, if you did a sport when you were younger, and how consistent you’ve been with running in the past six months. “Somebody who’s had more aerobic activity during their developmental years is going to be able to run more than somebody who maybe was more sedentary, or didn’t have a lot of activity in their adolescence or in their 20s,” says Hirt.
For example, she says, somebody training for a 5K at age 30 but who hasn’t run for five or more years will have a lower training age than someone who’s 25, but has been running for the last five years, three to five days per week.
Taking one to two months off after a big race to recover might decrease your fitness level slightly but it won’t affect your overall training age. Your training age starts to decrease once you reach about six months off from running or more, Hirt says. The more time you spend away from running, the less you’ll be able to tolerate more mileage.
“Yes, there are studies that show if you want to run fast, you have to run more,” says Hirt, but we often forget to consider that running more is a skill you build with time, effort, and patience. “People that are picking up running at the age of 30, might say ‘oh, I got to run 70 miles a week,’ but they’ve never even run 20 miles a week,” Hirt says. Start small, before you build up to high volume.
2. Injury Rate
It’s hard to add miles to your schedule if you’re constantly sidelined. That’s why injury-prone runners may naturally have lower weekly mileages, Hirt says, as they may find their bodies can’t handle the mechanical load at high volumes. These runners typically recognize their limitations and can tell when an injury’s lurking, she explains.
For example, if you find you always experience calf pain when you increase your volume by a few miles, or a recurring hamstring ache pops up during an increase in mileage, then you should keep that in mind when setting volume goals.
In this case, injury-prone runners likely stray away from higher mileages because they might cross-train with activities like swimming, cycling, or using the elliptical in lieu of extra miles. This is a smart way to maintain aerobic capacity, without the impact.
3. Time Restrictions
As a recreational runner, juggling your sport with work, hobbies, family, and a social life means having an honest conversation with yourself about how many miles you can realistically take on. If you simply don’t have time to run a certain amount of weekly mileage consistently during a given training cycle, then your weekly mileage is limited to what you truly can do.
This might mean finding your weekly mileage “sweet spot,” and sticking to that number rather than continuing to build off it. “If you’re thriving with your current mileage, don’t mess it up by adding more,” Hirt says. You might need to hang out at a certain mileage for a little while until your schedule clears up and you know you have enough time to recover when you do add more.
“Everyone’s got a different journey,” says Hirt. Some runners find the time for higher-mileage weeks, especially if they naturally run faster paces, because they genuinely enjoy it. Others squeeze in what their schedules (and paces) allow, and thrive on low-stakes, low-mileage plans because that’s what helps them feel excited and refreshed for every run. In either case, you can still have an amazing race no matter the distance.
When Mileage Matters Based on Race Distance
The race distance that demands more concern for weekly mileage is the marathon because it requires relatively high mileage compared to shorter distances, like a minimum of 30 miles a week (or more), says Hirt. “That’s really the one that we really just need to make sure you’re getting enough volume,” she says.
You’ll still base your mileage on training age and fitness level, how prone you are to injury, and your schedule, but you’ll still want to set minimum targets.
In general, though, if you thrive on high mileage, like up to 60 miles per week, you can stick with that volume while training for a 5K, as long as you include intensity. On the flip side, if you’re better off as a low-mileage runner, you can still train for your best marathon, leaning on cross-training and strength work for support. (A three-day marathon training plan may help you accomplish your goal, while keeping volume on the lower end!)
What really matters is that you genuinely enjoy your training and it keeps you healthy, Hirt says. “Don’t go after high mileage because you hear that’s what fast runners do or that’s what real runners do,” she says. “You have to want to do the run. Don’t do it because you think it’s required for the distance you’re doing.”
Kristine Kearns, a writer and avid runner, joined Runner’s World and Bicycling in July 2024. She previously coached high school girls cross country and currently competes in seasonal races, with more than six years of distance training and an affinity for weightlifting. You can find her wearing purple, baking cupcakes, and visiting her local farmers market.