Key takeaways
Most long runs belong at easy pace, roughly 35 to 100 seconds per km slower than marathon pace
Avoid making any run more than about 10% longer than your longest run of the past 30 days, a jump linked with higher injury rates
Add marathon-pace segments in the final 6 to 10 weeks before a marathon and practise fuelling with up to about 60 g of carbohydrate per hour
The weekly long run is the backbone of half-marathon and marathon training. Its pace is simple to get right and easy to get wrong: too fast and it becomes a race you have to recover from, too far too soon and it becomes an injury risk.
What the long run is for
A long run extends the time you spend at an easy aerobic effort. Over months that builds the adaptations that make endurance possible: more mitochondria, denser capillaries and a larger stroke volume, better use of fat, and legs and tendons that tolerate hours of impact. It is also where you rehearse race-day logistics: shoes, fuel, drinks and pacing.
Duration matters more than speed here. That is why most long runs are done at easy pace, inside the low-intensity majority of a polarised 80/20 week.
Long run pace
For most runners, long run pace is easy pace: conversational, roughly 65 to 79% of maximum heart rate in Daniels' model. Start at the slower end of your easy range. Heart rate tends to drift upwards over a long run even when pace is steady, especially in heat, so if your breathing or heart rate climbs out of the easy zone, slow down rather than fight it. Use the heart rate zone calculator to set the range, and see easy run pace for the talk test and a 5K-based chart.
Long run pace calculator
The VO2max running calculator gives easy, marathon, threshold and interval paces from a recent race or your VO2max, using Daniels and Gilbert's VDOT equations. Use the easy range for normal long runs and the marathon pace for any marathon-specific segments.
Long run pace vs marathon pace
The table shows model estimates from the VDOT equations: easy pace at 62 to 70% of VDOT, and the marathon pace and time the same equations predict from a 5K.
| 5K time | Long run (easy) pace per km | Marathon pace per km | Predicted marathon |
|---|---|---|---|
| 20:00 | 5:08 to 5:39 | 4:32 | 3:11 |
| 25:00 | 6:19 to 6:57 | 5:38 | 3:58 |
| 30:00 | 7:30 to 8:13 | 6:43 | 4:44 |
| 35:00 | 8:38 to 9:27 | 7:47 | 5:28 |
So long run pace is typically 35 to 100 seconds per km slower than marathon pace. One caution: race-based marathon predictions assume you have done marathon training. Many recreational runners run slower than predicted, so treat the marathon column as optimistic until your long runs and marathon-pace sessions back it up.
Why not run long runs at marathon pace? Because the long run is already the biggest single stress of the week. Running it at race pace every week makes it much harder to recover for threshold work and intervals, and the aerobic gains come mainly from the time on your feet, not the extra speed.
Long run pace vs easy run pace
The pace range is the same; what differs is duration and what happens late in the run. After 90 minutes, fatigue, falling glycogen and rising body temperature make the same pace feel harder. A long run that starts at the slow end of easy and finishes near the faster end is normal. A long run that finishes at threshold effort is not a long run any more. Form also tends to fade late in a long run; a light, quick step (see running cadence) and good running economy make the same pace cheaper.
How long, and how fast to build
- Cap it. A common coaching rule, used by Jack Daniels, keeps the long run to the lesser of about 25% of weekly mileage or 150 minutes for runners doing 40 or more miles a week.
- Avoid spikes. In a cohort of 5,205 runners tracked with Garmin devices over 18 months, a single run more than 10% longer than the longest run of the previous 30 days was linked with a higher rate of overuse injury (hazard ratio 1.64 for a 10 to 30% spike, and 2.28 for more than doubling it) (Frandsen et al., 2025). Weekly increases did not show the same clear pattern.
- Build in steps. Add a little distance every week or two, and include a shorter "down" week every third or fourth week, as in a periodised plan.
Fuelling the long run
For easy runs of up to about an hour, most runners do not need to eat. For longer runs, carbohydrate helps. Jeukendrup (2014) suggests up to about 60 g per hour for 2 to 3 hours of exercise, and about 90 g per hour for longer events, using mixed sugars such as glucose plus fructose at the higher rates. Lower intakes may be enough at slow, easy intensities.
The gut is trainable: practising race-day carbohydrate intake in training improves tolerance and may reduce stomach problems (Jeukendrup, 2017). Use your long runs to test gels, drinks and timing. If you suffer from cramps or nausea, see runner's stomach.
Marathon-pace segments
In the last 6 to 10 weeks before a marathon, some long runs can include work at goal marathon pace, for example:
- 20 to 25 km with the final 8 to 10 km at marathon pace;
- 25 km including 3 × 5 km at marathon pace with 1 km easy between.
These rehearse pacing and fuelling at race speed. In a survey of 139 recreational marathoners, higher weekly training volume and more long-distance race experience were associated with smaller slowdowns in the second half of the race (Swain et al., 2020). Keep these sessions to every second or third week, cut back during your taper, and run the rest of your long runs easy.
Safety: stop and seek advice if you have chest pain, unusual breathlessness, dizziness or pain that changes how you run. In hot weather, shorten the run and drink to thirst.
Frequently asked questions
What should my long run pace be?
Usually your easy pace, the pace at which you can still talk in full sentences. For a runner with a 25-minute 5K, model estimates put that at roughly 6:20 to 7:00 per km, compared with a marathon pace of about 5:40 per km.
What is the difference between long run pace and marathon pace?
Long run pace is easy pace, typically 35 to 100 seconds per km slower than marathon pace. Running every long run at marathon pace makes recovery much harder and adds little extra benefit for most runners.
Is long run pace the same as easy run pace?
Mostly yes. The long run uses the same easy range, often starting at the slower end and drifting a little faster later. Effort rises over a long run even at a steady pace, so judge it by breathing and heart rate as well.
How do I use a long run pace calculator?
Enter a recent race time or your VO2max in a VDOT-based running calculator and use the easy range it gives. Marathon pace from the same calculator tells you how fast to run any marathon-pace segments.
Sources
- Daniels J. Daniels' Running Formula, 3rd ed. Human Kinetics, 2014.
- Frandsen JSB, et al. How much running is too much? Identifying high-risk running sessions in a 5200-person cohort study. Br J Sports Med, 2025.
- Jeukendrup A. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Med, 2014.
- Jeukendrup AE. Training the gut for athletes. Sports Med, 2017.
- Swain P, Biggins J, Gordon D. Marathon pacing ability: training characteristics and previous experience. Eur J Sport Sci, 2020.