If you’re training for a marathon or half, you likely have a fairly specific fitness schedule that details how many days a week to run. If an event isn’t on the calendar, you might just log some miles here and there, willy-nilly, on whatever days you feel like it. But even if race performance isn’t on your radar, it pays off to pay attention to the number of days you’re running each week.

Whether you hope to BQ (Boston qualify) or just reach the finish line, to unwind or burn some extra calories, it’s crucial to consider how often you’re lacing up your sneaks if you want to get the most out of it. “I’d say the biggest reason you want some sort of regular schedule to running is the more you do, the better you feel doing it,” says Malindi Elmore, an Olympic runner and coach at the Run S.M.A.R.T. Project. “If you’re running once or twice a week or irregularly, you don’t get into a good rhythm—so it always feels hard. It takes a certain level of running fitness to feel good.”

It’s crucial to consider how often you’re lacing up your sneaks if you want to get the most out of it.

On the other hand, pound the pavement or hit the treadmill too often and you can end up sick, injured, tired, and burned out. It’s all about finding a happy medium.

Of course, that happy medium is different for everyone. “It’s very dependent on the person,” says Shiva Douse, co-founder of RacePace running studio in Houston. “When we build a plan, we think about three different components. Whether you’re getting ready for a race or are just a recreational runner, these three components apply: your history as a runner, your goal, and all the other factors in life that can affect your ability to run on a daily basis—like time commitments and how much you sleep.”

Want to know how to dial into the optimal number of running days for you? Read on for expert advice based on what you want to get out of your miles.

If you’re a running newbie

When you’re starting out, the name of the game is gradual progression. “Doing too much too soon can result in injury or burnout,” says Stacy Sims, PhD, an exercise physiologist and sports nutritionist who specializes in how men and women train and perform differently. Jumping in prematurely can even cause weight gain, she says, because fatigue and overuse both raise your cortisol levels and encourage fat storage.

It’s better to add frequency before adding volume, says Elmore. She suggests beginning with a run-walk approach: Run for 30 seconds, walk 4 1/2 minutes, and repeat 5 times (30 minutes total). Do this 3 times a week, adding 30 seconds of running during each outing until you work up to about 30 minutes of running. Sticking to 3 or 4 days of running a week leaves you time to cross-train with yoga, swimming, or strength training, says Elmore—to help you sidestep injury.

If you want to tackle 10-milers with your friends

Once you have some long runs or half marathons under your belt, you might be tempted to skip a few of those weekday miles and just go out for a long run come Saturday morning. The problem with being a weekend running warrior? It shocks your soft tissues, says Elmore. “I don’t think it’s ever really recommended that you do a long run without supporting runs,” she says. “Your long run shouldn’t be more than 20 percent of your weekly mileage. It’s detrimental to your muscles and tendons.”

Instead, aim for that long weekend run and at least a few other runs to fill out your week. They can be an easy pace if you don’t have a race or goal time in mind; if you do, make sure at least one workout is a fartlek (AKA switching between sprinting and jogging), hill intervals, or some kind of speed work. “Depending on your training history, you might be able to get by on fewer days, but only one or two days a week won’t let you build,” says Sims. “You need at least three or four days of planned sessions.

If you’re training for a marathon

When you’re gearing up to cover 26.2 miles in one day, you don’t want to skimp on how many days a week you’re running. But the exact number of sessions can vary, depending on what you hope to do once you toe that start line. Just want that finisher’s medal around your neck? Three or four days might be adequate, says Elmore. But if you want to PR or qualify for Boston (AKA the brass ring of marathon races), amp that up. “Improving your time is a huge difference, and you’ll need a fair amount of running under your belt,” she says. Elmore advises five days of running a week, and two of those should be some kind of quality speed work.

Want to swap out one or a couple of those runs for an elliptical workout or other kind of cardio? It’s usually not the best strategy, says Elmore. “The thing about running is it’s so specific, and the load-bearing aspect is so different than any other sport,” she explains. “If you’re just swimming or biking, you’re not loading your muscles in the same way. So when you go out for those really long runs, they can end up breaking down.”

If you want to tone your body

The good news is that to get toned, you don’t have to add tons of weekly runs to your calendar. You just need to make sure the runs you do are quality.

“The biggest thing people don’t do effectively that certainly helps with burning calories and body composition is adding intensity,” says Elmore, who suggests three or four weekly runs and making two of them quick-paced sessions like a fartlek, tempo run, or hill repeats. “Those workouts add variety and are a huge bang for your buck,” she says.

Sims also recommends having two speedy interval workouts and one or two easy runs, plus two days of strength training in the weekly mix. The weight training will not only help your body burn fat and boost your metabolism, it’ll also improve your strength and help you avoid injury in the long run, she says—so you can keep exercising and maintain that physique.

If you’re super-stressed and just need to clear your head

“Stress relief is a beautiful thing that running does for you,” says Douse. She recommends thinking about when a run seems to offer you the most peace of mind and basing your weekly schedule on that. Like to calm yourself with an early morning run a couple days a week? Pick two or three days and plan to lace up your shoes then. If hoofing it at lunchtime or as soon as you clock out at night leads to the greatest stress reduction, run right after work four or even five days a week to reap that relief. Elmore suggests running outdoors—somewhere in nature if possible—and leaving the GPS watch at home to help yourself “get lost in the moment and get in the zone.”

Whatever you do, whenever you run, don’t forget that your initial reason for doing so was to de-stress, says Douse: “If unwinding is your main goal, don’t let a missed run become another source of stress.” It’s better not to, er, sweat it. 

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