There’s no worse feeling than when you set out for a long run and start to feel like trash before the first song on your playlist even finishes. When your long run becomes a struggle, it can make slogging through it draining, uncomfortable, or even impossible—and it can leave you with a bad feeling that often spills over to the rest of your training schedule, too.
But struggling on a long run doesn’t mean you lost fitness or need to kiss your goals goodbye.
“It can be reassuring to recognize that there are multiple reasons a long run can feel difficult,” Amanda Katz, CPT, a certified run coach and host of The Running Explained Podcast, tells Runner’s World. “It’s not a failure.”
Your nutrition, training program, and non-running life can all play a role. Asking yourself a few pointed questions can help you dig into which issues might be behind your struggle—allowing you to zero in on some potential strategies to help you feel better as you go longer.
What did you eat before your run?
Choosing nonideal foods right before your run, not eating enough, or running fasted can all cause long run struggles, Amanda Wagner, RDN, a registered dietitian and certified run coach at Filla Endurance, tells Runner’s World. For example, eating options high in fat or protein—say, a handful of mixed nuts—can lead to GI issues, as they take longer to digest than carb-rich options.
Many runners also just grab a bite of their kids’ breakfast and head out the door or they exercise in the early morning and don’t eat anything at all. These habits can all prove problematic, Wagner says.
Running without adequate fuel can also trigger GI issues like nausea or cramping. “But it’s much more likely to cause dizziness, bonking, feeling depleted, or having no energy for the rest of the day,” says Wagner.
Try taking in a solid source of carbs 20 to 60 minutes before your run, like applesauce packets, graham crackers, gummy snacks, or a carb-heavy sports drink like Gatorade or Skratch, she says. If you have more time—say, two to three hours—you can add in some protein and fat for satiety. This could look like eggs and toast, a bagel with peanut butter, or a bowl of oats with fruit.
When did you take your first gel?
If you waited until you’re an hour into your run (or, even worse, answered “what gel?!”), you might be digging yourself into a hole, says Wagner. When you put off taking fuel, your carb stores aren’t getting replenished, which can affect your energy and how strong you feel.
Starting your gels at the 20- or 30-minute mark would likely help you feel better, she says. “When you’re taking it earlier in your run, you’re giving your muscles the carbohydrates to use right away; it’s almost like a preventive measure,” Wagner says. “You’re giving yourself the fuel before you become completely depleted.”
Take in carbs early and often—it’s not a one-and-done thing. Shoot for at least 30 to 60 grams per hour for durations lasting longer than 60 minutes, per a position statement published in the Journal of the International Society of Sports Nutrition.
Do you notice white flakes on your body or clothes?
That white stuff is salt, and if you see streaks of it on your face, neck, or clothing during or after your long runs, it could indicate that you’re a salty sweater. And if your hydration strategy doesn’t account for that, it could leave you feeling gassed. “It’s also more likely to cause cramping, which could also be slowing you down,” says Wagner.
You want to make sure your overall fluid replenishment is on target—generally 7 to 10 fluid ounces every 10 to 20 minutes or so, though it depends on your sweat rate, per the National Athletic Trainers’ Association. (You also want to fill up before the run with 17 to 20 fluid ounces two to three hours before your run, and 7 to 10 fluid ounces 10 to 20 minutes before you start.)
But if you’re losing lots of sodium in your sweat, hydrating with pure water might not be enough. Try adding in electrolytes, whether it’s a sodium-containing gel, salt capsules or chews, or a drink mix, says Wagner.
“See how you feel with having some sort of salt strategy, and if that’s not making you feel better or you want to really know how much sodium you’re losing, a referral to a sports dietitian can help,” she says. They can work with you to find out your sweat rate and give personal recs for fluid and electrolyte replenishment.
Were you able to talk comfortably during long, slow distance runs?
“If someone tells me that they’re feeling completely wiped after every long run, they’re dreading them, or they’re fading at a certain point, that tells me that they could be going at an intensity that is not appropriate for them,” says Katz.
For long runs that don’t include any pace work, you should be able to hold a comfortable conversation during the whole thing or sing out loud to your favorite song. It should feel like about a 3 on a scale of 1 to 10, with 10 being all-out effort.
Slow down your pace until you’re running at an effort that falls inside this easy range. “If you need some guidance or guardrails, just try to go 20 to 30 seconds slower than you had been going,” says Wagner. This should help dial down your effort so you’re able to complete your session feeling stronger.
Are you adding in workouts your body isn’t ready for?
A scroll through social media might make you think that everyone is doing long run workouts, but many runners aren’t quite ready for the added strain pace work brings—particularly if they’re new to building distance, according to Katz. “We don't want to progress intensity and mileage at the same time,” she says. Doing so can leave you feeling gassed, down on yourself, and under-recovered.
Trust in the base-building phase, focusing on adding distance while keeping your pace easy. Once you feel comfortable at that mileage, keep that steady while gradually introducing a bit of speed, says Katz. Start small, like with 20- to 30-second strides in the middle or end of your long run.
“Training is like a cake,” Katz says. “It has layers to it—you can’t bake it and frost it at the same time.”
What else is going on in your life?
If the answer is all of the things, it’s not surprising that your long run may feel more challenging than usual. Hectic work deadlines, packed carpool schedules, caregiving responsibilities, a move, or a breakup all can affect your body physiologically. “Your body doesn’t separate the stress of marathon training from that,” says Katz. “It’s all stress.”
Stress can affect how you’re sleeping, eating, and recovering, as well as your motivation to lace up—all of which can influence your running.
If you have a ton going on in your everyday life, you might want to tweak your training schedule to account for it, says Katz. This might look like shortening your long run, adding in walk breaks, dialing back the intensity, or taking a deload week. “As runners, we get accustomed to this very rigid mindset around our training, that it’s all or nothing,” she says. “But there’s a way to adjust the plan so that it remains a sustainable part of your life.”
Was this a one-time thing or has it been a consistent issue?
This is a big one: Whether your long run struggle was an isolated off-Saturday or part of a bigger pattern can be telling. “Like anything in life, other things are going to show up—maybe you didn’t sleep well or eat enough the night before, or there was a heat wave you had to deal with,” says Katz. All of those can mess with how you feel during a run, but they’re not things to freak out about. “It could be just one isolated run.”
On the flip side, if you’ve felt the same depletion over the past three or four long runs—especially if your other runs are feeling worse too—this might signal more of a pattern, she says. If life stressors are causing it, you may want to tweak your plan accordingly, like we mentioned above, to avoid adding more cumulative stress.
But if you’re still feeling lousy after trying some tweaks, especially if you’re dealing with persistent fatigue during and outside of your runs, you may benefit from getting bloodwork done to check your levels of iron, ferritin, vitamin B12, and thyroid hormones, says Wagner. This could help ID whether deficiencies might be causing or contributing to your running struggles.
For nearly 10 years, Christa has created health, fitness, nutrition, and wellness content that’s steeped in science but engaging enough that people actually want to read it. She’s tuned in to all the latest research that people with an athletic lifestyle need to know, and prides herself on helping her readers apply it to their everyday lives.
