The long run is the most important single session in your week — and also the one most runners overthink. How far is far enough? How fast should you go? When do you increase? When do you stop increasing?
The answers depend on where you are and what you’re training for. But the principles are universal.
How Long Is “Long”?
Your long run should be your longest run of the week — that’s what makes it a long run. But it shouldn’t dominate the week. Pacewright keeps it in proportion to your total volume, so one session doesn’t eat so much of your recovery capacity that the rest of the week suffers.
Your long run scales with your total volume, not with an arbitrary distance target: as your weekly mileage grows, your long run grows with it. And until your volume can support a run that’s genuinely long — longer than your easy days and long enough to matter — Pacewright holds off and builds your base with easy running instead.
If you’re training for a marathon and wondering about the classic 20-mile long run: most recreational runners don’t need one. A long run kept in proportion to a consistent weekly volume, built up gradually, carries the vast majority of finishers to the line. Showing up week after week matters far more than chasing a single hero distance.
How Fast Should You Go?
The long run is an easy effort — RPE 4-5. You should be able to hold a conversation throughout. The purpose isn’t to practice running fast. It’s to accumulate time on your feet at an aerobic intensity that builds endurance-specific adaptations.
Those adaptations include:
- Improved glycogen storage and utilization. Your muscles learn to store more fuel and burn it more efficiently during sustained effort.
- Enhanced fat oxidation. At easy effort, your body increasingly relies on fat as fuel, sparing glycogen for when you need it.
- Mental endurance. Running for 90+ minutes teaches you how to manage boredom, discomfort, and the urge to stop — skills that translate directly to race day.
- Structural resilience. Extended time on your feet strengthens the connective tissues — tendons, ligaments, fascia — that absorb impact.
Running your long run too fast turns it into a different workout: one that accumulates fatigue without providing the aerobic benefits you’re after. A long run at RPE 7 isn’t a better long run. It’s a badly paced tempo that you’ll need extra recovery from — and that recovery cost means your other workouts suffer.
How to Progress
Your long run follows the same spike guard as every other run: it can only step a little past your longest run of the last month. The progression is gradual because the tissues that absorb impact — bones, tendons, cartilage — adapt slower than your cardiovascular system. In the largest study of runners to date, sessions that went past about 10% of a runner’s longest run in the previous 30 days carried a higher rate of overuse injury.
Here’s the shape of a gradual build from a 6-mile long run to a 10-mile one. You add roughly half a mile at a time, never stepping far past your recent longest, and every few build sessions you pull the long run well back below your recent peak before you resume and climb again. From a 6-mile baseline you might edge up toward 7, cut back to around 5, resume near 7.5 and build to 8, cut back once more, and eventually reach 10 as a new peak.
That cutback isn’t wasted time — it’s when your body consolidates the adaptations from the harder sessions. And none of it runs on fixed weeks: Pacewright adds distance when your recent training supports it and pulls back when you need it, so the actual timing follows your body, not a row on a schedule.
When to Hold Steady
Not every phase of training calls for longer and longer runs. There are good reasons to keep your long run at its current distance:
- You’re in a base-building phase and the focus is on increasing total weekly volume, not single-run distance
- Your weekly mileage doesn’t yet support a longer long run (pushing it further would let one session dominate the week)
- You’re focusing on speed — 5K or 10K training plans emphasize intervals and tempo work, with a moderate long run that maintains endurance without chasing distance
- You’re in a recovery or deload period and the plan has deliberately pulled the long run back
A 10-mile long run every weekend for 8 weeks straight is excellent training. You don’t have to increase it just because you successfully completed it last week.
Walk Breaks on Long Runs
Walk breaks are a legitimate strategy on long runs, not a sign of weakness. Taking a 1-minute walk break every mile or every 10 minutes reduces cumulative muscle damage, helps manage heart rate drift, and allows you to cover more total distance than continuous running at the same perceived effort.
Many experienced runners use walk breaks specifically on long runs while running their shorter sessions continuously. It’s a tool for managing the demands of extended time on your feet — not a substitute for fitness.