5 Reasons Your Pace Is Getting Slower—and What to Do About It

Easy runs, by definition, should be laid-back. You shouldn’t be huffing and puffing or stressing about your speed. It can be frustrating, though, if you keep finding your pace getting slower or if your regular pace isn’t feeling so easy anymore.One or two off days where you’re moving noticeably more slowly than usual can be annoying but nothing to worry about, says Zach Tacy, running coach and certified personal trainer at Life Time Walnut Creek. So many factors can lead to a slower outing here or there—like if you’re dehydrated one morning or if it’s especially hot or humid outside.Another common reason you’re running more slowly for a day or two is that you’re coming off a tough workout. A slower pace during a run after a speed session or long training run is expected—and important. “Recovery runs should be deliberately slower than easy runs,” says Laura Norris, owner and coach at Laura Norris Running in Boulder, Colorado. “They allow a runner to get in more training volume, such as five to six days of running per week, without causing more fatigue after a hard workout.”Your easy pace may slow down longer than a few days if you’re deep into intense training, such as for a marathon; that’s still nothing to worry about as long as your pace for speed workouts isn’t slipping, says Norris.If your easy pace has been slipping consistently for a few weeks and you’re not in a tough training cycle, though, or if your easy runs and speedwork are both slowing, there’s likely something going on that you need to address. “A slower easy pace doesn’t automatically mean you’re losing fitness; you could be overtraining and hitting a fatigue wall and the body is just stacking fatigue instead of building fitness,” says Tacy.Here are five factors that could be leaving you overtrained or otherwise unprepared for your easy days, making your regular pace feel way harder than usual—plus tips about how to zero in on which one(s) could be slowing you down.Inadequate RecoveryIt could be the culprit if: Your legs feel heavy, you’re experiencing a higher rate of perceived exertion (RPE) over multiple runs, or you recently finished a hard training block.What’s going on: “A poorly managed training load can contribute to inadequate recovery,” says Norris. If you stack multiple hard workouts too close together, for instance, your muscles never get enough time to repair and you wind up feeling zapped during even easy efforts. “Inadequate recovery will impact all systems—muscular, neural, hormonal, etc.—and lower the body’s ability to produce contractions to slower paces,” she explains. The best fix: Make sure you’re spacing tougher sessions (both long runs and any speed workouts) far enough apart throughout the week, says Norris. Adding an extra rest day is better than pushing through and risking overtraining.Improper NutritionIt could be the culprit if: You’re feeling flat, fading during runs, experiencing higher RPE, or struggling to recover.What’s going on: “Easy runs use both fats and carbs to produce energy,” says Norris. “If not enough carbs are available, your body will force you to slow down to a pace that can rely more on fat oxidation.”The best fix: This doesn’t mean you necessarily need to eat carbs right before you head out on every run. One meta-analysis of 46 studies found that a pre-exercise meal improved performance for longer aerobic workouts but not shorter ones. But it’s worth looking at what you’re eating before your runs and overall to make sure you’re getting what you need to stay fueled up.Depending on how much you’re running and your goals, runners need between about 3 and 6 grams of carbs for every kilogram of bodyweight per day (to calculate, divide your bodyweight in pounds by 2.2). Keep in mind that if an easy run lasts longer than an hour, you also should be refueling with easily digestible carbs mid-run, too.Poor SleepIt could be the culprit if: You experience a higher RPE, sluggishness, and/or a slower pace at the same heart rate.What’s going on: Sleep affects how well your endocrine system functions, so not resting well can impair your endurance and power output. “Poor sleep will leave you under-recovered from the previous day’s training, resulting in a slower easy pace,” says Norris. “Even if you slept poorly coming off of a rest day, you would still experience a higher rate of perceived exertion (RPE) on easy runs.”You don’t have to be tossing and turning night after night to feel the effects; a single night of sleep deprivation is enough to mess with recreational runners’ biomechanics and running economy, according to one new, small study in Medicine & Science in Sports & Exercise. Similarly, runners who got insufficient sleep ran more slowly and with less efficiency the following day in a recent Frontiers in Physiology study.The best fix: It’s important to prioritize getting quality Z’s every night. If you had one night of bad sleep but got at least five to 6.5 hours, it’s okay to go for the run you had scheduled, but Norris recommends listening to your body and scaling back your effort or distance if necessary. If you got less than 5 hours, it’s better to sleep in and skip the run.Better sleep hygiene—like skipping screens, going to bed earlier, and keeping your room cool—can all help with better Z’s but sometimes it’s more serious, like high stress or a health issue causing sleep trouble, and that’s worth getting to the bottom of before a big training block, Norris says.AgingIt could be the culprit if: You’re 50+What’s going on: As your age creeps up, your pace probably will too—but not until you hit about 50. This is the age when both men and women runners began to gradually slow down in research in PLoS One that looked at data from 16 years of the New York City, Boston, and Chicago marathons. “The shift tends to be gradual, only a small amount each year, and it can be partially mitigated by training,” notes Norris.The best fix: Norris recommends resistance training and running strides to help preserve muscle function and cut back on some of the pace decline you might be noticing.Tacy agrees, adding, “Recovery may gradually take longer, but many athletes maintain or improve their pace well into their 40s, 50s, and beyond.”Lack of SpeedworkIt could be the culprit if: You’re doing only easy runs and have hit a fitness plateau.What’s going on: “Easy runs feel good and are good for building endurance, but over time, without speedwork—like thresholds, tempos, progressions, and sprints—most runners will hit a plateau or may even see a regression in pace and fitness,” says Tacy.The best fix: You don’t have to do faster workouts if your slower easy runs don’t bother you, but if you want to see your pace improve, adding some speedier sessions into your week could be the key. You can start with something simple like adding strides at the end of an easy run, then progress to short intervals and then tempo runs.The Bottom LineWhile a slow run here or there may be discouraging, try not to make too big a deal out of it. “The biggest thing is, don’t diagnose yourself from one slow run,” says Tacy. Instead, looking for patterns in your routine and your pacing should help you pinpoint what’s holding you back—and then you can get back up to speed.Laurel Leicht is a writer and editor in Brooklyn. She's covered health, fitness, and travel for outlets including Well+Good, Glamour, and O, The Oprah Magazine.