Bad days are a part of life—and bad runs are a part of running. While bad runs happen to everyone (even the pros!), there are still things you can do to prevent them from becoming status quo.
And that’s important, because a bunch of lousy runs stacked together can lead to a full-on running slump, which is a lot harder to overcome than a single subpar workout.
🏃🏻♀️ Escape your rut and get back into running again with The Runner’s World Guide to Getting Out of a Training Slump.
A key part of sidestepping bad runs is identifying what causes them in the first place. Sometimes, the trigger is super obvious—for example, you rolled your ankle during the warmup or had an explosive case of GI distress. But other days, your runs feel like crap for no apparent reason. In the latter scenario, there usually is a reason; it just takes more effort to pinpoint.
To help with that process, we rounded up nine sneaky culprits behind your bad runs, along with expert advice for dodging them next time.
1. Environmental challenges.
It’s probably not a shocker that hot weather can tank performance. What’s less obvious: The point at which the heat can sour your workout is lower than you might think, exercise physiologist Janet Hamilton, founder of Running Strong in Georgia, tells Runner’s World.
In fact, even temps in the 60s can subtly sabotage performance. The exact impact is different for every runner, but generally speaking, the average athlete can expect to slow by 20 to 30 seconds per mile for every 5-degree increase above 60 degrees Fahrenheit, as Runner’s World previously reported. So if you’re running on a 75-degree day—which probably doesn’t feel all that hellish—your pace could be up to a minute and a half slower than what you’d clock on a 60-degree day.
The reason even moderate temps can zap performance boils down to blood flow. The hotter your core gets thanks to the combo of exercise and warm weather, the more blood flow it will demand to help cool it off, Hamilton says. And when more blood flow is directed to your core, less is available to power your working muscles, which compromises performance, she explains.
Same goes for humidity. “Even if it’s not terribly warm, humidity [decreases] your body’s ability to evaporate sweat,” Hamilton says. Only sweat that evaporates from your skin cools you, she explains, so in humid conditions, when sweat just drips off you instead of evaporating, your core temp will be higher. As a result, more blood will be shuttled there instead of to the muscles powering your run.
Then there’s the wind effect. “People think the wind keeps you cool,” Hamilton says. And while that can be true in some scenarios, the wind can also provide unwanted resistance, especially when you’re running right into it. But what if the wind is at your back—wouldn’t that provide a welcome assist? “Unfortunately, the boost of running with a tailwind is not as great as the penalty of a headwind,” Hamilton says.
Lastly, running in cold weather—think: anything below 10 degrees Fahrenheit—can take its toll. That’s because your body is more focused on maintaining your core temperature and warming the cold air before it reaches your lungs than it is on powering an efficient stride, as Runner’s World previously reported. Then, if you add snow and ice on top of that, which requires your muscles to work harder to stabilize you as you stride, your run will likely feel that much harder.
How to avoid it: You can’t control the weather, but you can reduce its impacts by dressing appropriately (more on that in a minute). Following our expert-backed tips for smart running in the heat, humidity, and cold can help, too. Finally, when outdoor conditions aren’t 100 percent primo, consider adjusting your goals for the run. You may not be able to hit your target paces, so focusing instead on things like maintaining good form or holding a steady effort can help the run still feel successful.
2. Donning too many layers.
Even when the weather conditions are ideal, you can still biff it by overdressing. Kai Ng, a USATF- and RRCA-certified run coach in New Jersey and New York, tells Runner’s World he frequently sees this mistake among runners in New York City, some of whom wear long tights, beanies, and big headphones on summer runs. “I have nothing against big headphones, but they’re trapping so much heat on your head,” he explains. When you dress too warmly for the conditions—which is possible even during winter runs—you risk overheating, which can hamper performance and make the overall workout less enjoyable.
How to avoid it: When picking your outfit for a run, dress like it’s 15 to 20 degrees warmer than it actually is, as Runner’s World previously reported. In cold temps, that often means getting strategic with layering. “One of the biggest hacks for wintertime running is layering long sleeves because [if you heat up,] you can always take off one layer and tie it around your waist,” Ng says. Learn more with our guide to properly layering for spring, fall, and winter runs.
3. Different running terrain.
Maybe you usually run on the roads, but today you meet up with a friend who takes you on a trail run. Even though the trail itself is relatively level without big elevation changes, it’s still more challenging than striding on asphalt, thanks to the uneven surface that challenges your stabilizer muscles and causes you to pick up your feet a little higher than usual, Hamilton explains. That low-grade difficulty can add up over the course of the run, leaving you a lot more gassed than usual by the time you finish.
Or, perhaps you swap your typical flat neighborhood loop for a new route that includes a series of small, rolling hills. “They’re not super high; you’re plenty capable of running them,” Hamilton says, which means you may not think much of it. But doing more hill work than you’re used to—even if it’s subtle—can tax both your cardiovascular system and your muscles, the latter of which has to work harder to power you up the inclines and control you as you descend. The result: You finish your run feeling zonked.
How to avoid it: When running on new-to-you terrain, let effort (not pace) guide your run. As long as you run at the same effort level that your workout originally called for, you’ll still get the same training benefit, Hamilton explains. Knowing this ahead of time can help you appropriately pace your run versus going out too hard and feeling the effects of that later.
4. Hydration or nutrition glitches.
Are you thirsty right now? If so, you’re already mildly dehydrated. That may sound like NBD, but even mild levels of dehydration can hamper your performance, Hamilton says. “Obviously, the longer the training run is going to be, the more significant that impact will be,” she explains. “If you’re just going out for a 30-minute quickie, it’s probably no big deal,” she says. But if you’re aiming for an hour-plus workout, even low-grade dehydration can ratchet up your heart rate and increase your chances of muscle fatigue and cramping.
Along those lines, not eating enough before lacing up can also zap performance, Ng says. “It’s like going on a road trip without stopping at the gas station,” he says. Without proper prerun fuel, you might struggle to hold your paces and may even feel dizzy.
How to avoid it: To avoid dehydration, scope your pee before you head out the door. If it’s fairly dark, then you should probably hydrate more, Hamilton says. You can do so by drinking a glass of water with electrolytes in it and then bringing fluids with electrolytes with you to sip while you run. On the food front, aim to have about 20 to 30 grams of simple-to-digest carbs 15 to 60 minutes before your run, with more possibly needed depending on how long you’re planning to exercise, as Runner’s World previously reported. Learn more about the nitty-gritty of prerun fueling with the experts’ tips we rounded up here.
5. A poor night’s sleep.
Getting enough quality sleep is essential to overall functioning and run performance. Research shows sleep deprivation can harm aerobic endurance and make exercise feel harder than it would otherwise. So while you may forget about a bad night’s sleep once that first cup of coffee hits, the effects could very well carry over into your workout, zapping your focus and making you feel sluggish and drained.
How to avoid it: Obviously you can’t undo a bad night of sleep, but you can reflect on what made it crappy so you’re able to avoid those pitfalls next time, Hamilton says. For example, maybe a Netflix binge caused you to go to bed later than usual, or a stiff back had you tossing and turning all night. “Figure out if you can pinpoint factors that led to the sleep disruption, then make a mental note and try to deal with those,” Hamilton says.
6. The shoes you wore last night.
Even if you don’t regularly wear high heels, sometimes the occasion calls for them, such as a wedding, work party, or other fancy event. If you spend several hours dancing and standing around in heeled footwear you’re not used to, your muscles—particularly your calves—“will be a bit more fatigued the next morning,” Hamilton says. This can carry over into your run, making the push-off phase of your stride feel less powerful than usual.
How to avoid it: Wearing non-heeled dress shoes is the most obvious solution, but if you’re committed to heels, you can reduce next-day calf soreness by prolonging your prerun warmup with a few extra minutes of walking and some gentle calf stretches, Hamilton says.
7. Ignoring how your body feels during the warmup.
Sure, it helps to have a specific plan for your run—especially if you’re training for a race—but it’s also important to tune into how your body feels each day and adjust the workout approach if needed. Neglecting this step can lead you to push yourself too much on days when you’d actually benefit from a gentler approach. And that’s a surefire recipe for a bad run.
“If anything is going on either during your warmup or during your run, I tell people, listen to the whispers of your body, and if you do that, it won’t have to shout at you,” Hamilton says.
How to avoid it: Use the warmup as a time to tune in with your body. Are you feeling any pains, aches, or unusual tightness? If so, prolong your warmup and see if the discomfort eases. If not, then adjust your goals for the run based on that feedback.
8. Not actually resting on rest days.
A common mistake Ng sees runners make is using their “rest” days for strength training. And while strength training is an important component of running strong and reducing injury risk, never giving your body an off day to recover leaves your muscle fibers constantly fatigued, which means they aren’t able to show up strong on your runs. Translation: You’re more likely to have a bad run (or several).
How to avoid it: The recommended cadence of rest days varies based on factors including your fitness level, goals, and how your body responds to training, but as a general rule of thumb runners should aim for one to two rest days a week. Ng, for his part, suggests sprinkling rest days into a weekly schedule that includes three to four days of running, one day of mobility work, and one day of strength training.
9. Lingering stress.
Running can be a great stress-relieving activity, especially on the heels of a tough day at work or after an argument with your significant other. But sometimes, lingering life stress can permeate your run, distracting you from the workout at hand and making the overall session less enjoyable and effective.
How to avoid it: If you’re leaving behind a tense situation to go on a run, consider doing a few minutes of deep breathing or meditation first to help you be more mentally present for your workout. Or, try this mental reframe from Hamilton: As you walk out the door, tell yourself that you’re leaving your stressors behind you and moving toward your run, which is “fresh and new and completely unrelated to what is back there,” she says.
Jenny is a Boulder, Colorado-based health and fitness journalist. She’s been freelancing for Runner’s World since 2015 and especially loves to write human interest profiles, in-depth service pieces and stories that explore the intersection of exercise and mental health. Her work has also been published by SELF, Men’s Journal, and Condé Nast Traveler, among other outlets. When she’s not running or writing, Jenny enjoys coaching youth swimming, rereading Harry Potter, and buying too many houseplants.