Running a marathon takes a massive chunk of time; it doesn’t matter whether you’re a total beginner or an elite athlete. But while the actual race is long, training for it takes way, way longer. Regardless of what marathon training plan you’re following, most runners will be logging multiple hours of miles each week gearing up for 26.2. Which means other obligations and commitments often have to take a back seat, especially when it comes to that weekly long run.
But what happens on the days where you just can’t make it happen? There are two different ways runners typically break up a long run — which helps racers build experience and endurance leading up to race day: Divide it up over the course of two days, or take smaller breaks during a sustained same-day effort.
Here, experts weigh in on whether or not it’s OK to break up your long run in both scenarios.
Bathroom breaks, bumping into a friend you haven’t seen in forever, traffic, an unexpected phone call: There are a lot of potential reasons your long run can get interrupted. But is the start/stop method — pausing for 10–20 minutes here and there — going to mess up your progress?
“If the breaks are just a few minutes, the impact should be minimal,” says Rebekah Mayer, National Run Program Manager at Life Time. “The primary goals of long runs include adapting to time spent on your feet, and overall cardiovascular adaptations due to the volume of exercise. Taking brief breaks does not diminish the total time spent running, so that adaptation should be preserved.”
Breaks do impact heart rate, however, Mayer adds. “A runner’s heart rate could recover significantly during a break, possibly decreasing the overall intensity of the effort,”she says. “The impact on this depends on the goal of the workout.”
Aiming to simply build up mileage at an easy pace? Then this break isn’t a big issue. However, if you’re trying to get more intense — like simulating a marathon goal pace — the rest could remove the benefit of having a long stretch of training at that pace.
If you do have to start, stop, then start again, then there are a few best-practices. Primarily: Start (back) slow, urges Mindy Solkin, founder of The Running Center. “Muscles and connective tissues get stiff and cold. Plus, when you were running, your heart rate was at a sustained level of approximately 75–85% of max heart rate,” Solkin says. “Give your body time to get used to the effort again.”
Wedding weekends, family visits, a daycare mix-up, a major presentation at work … These types of snafus can mess up a planned long run time block, but dividing a run over the course of two days when you’re in a bind should be rare. After all, the purpose of long runs is to run long.
“These longer runs teach your body to store glycogen (a carbohydrate) in your muscles, thereby utilizing fat more efficiently,” says Solkin. “They also help your cardiovascular, muscular and connective tissue systems get used to the weight-bearing impact and allow for the training effect to occur. When you break up the run into two shorter runs, you don’t get the same impact.”
One caveat to this rule? Depending on your pace, it’s important to examine how long you’ll be on your feet during a long run, advises Mayer. “The injury risk inherent with long runs increases dramatically beyond a 3-hour run,” she says. “If that duration doesn’t match with the mileage you would like to cover, it may be beneficial to schedule a 3-hour run, and then return with a second run of a shorter duration the following day.”
For the rare occasion you must split it up, Mayer suggests runners plan to fit as much of your long run volume into the first day as possible, then add the remainder to your run the following day.