Marathon training plan,
on your Garmin.
The marathon is not a long 10K. It is a different problem, where the limit is usually fuel and accumulated fatigue rather than raw speed. Most marathon failures are decided in weeks eight to twelve of the build, long before the start line, by doing too much too soon.
What a marathon week looks like
Build length: 16 to 20 weeks
Weekly volume: 60 to 100 km a week
Five to six runs. A long run building to 30 to 35 km, one session at marathon pace, one threshold session, the rest easy, with a down week roughly every fourth week.
The session that decides your marathon
Long runs with marathon-pace blocks. A 28 km run with the last 10 km at goal pace teaches your legs what race pace feels like when they are already tired, which is the only state that matters.
The mistake almost everyone makes
Fuelling for a marathon
Central, and it needs training like anything else. Most runners target 60 to 90 grams of carbohydrate an hour and have to teach the gut to tolerate it over months. An unfuelled marathon is the classic way to meet the wall at 32 km.
Which Garmin metrics actually matter here
- Training load and acute load, to keep the ramp honest
- Long-run heart-rate drift, an early warning of overreaching
- HRV status, which falls before you consciously feel wrecked
- Race predictor and PacePro, for a goal pace grounded in reality
How to get this plan onto your watch
- Free option, Garmin Coach: covers 5K, 10K and half marathon plans and pushes each workout to the watch. There is nothing for the marathon or ultra distances, and none of it is built around your specific race date.
- Adaptive option, Custom Gains: say your race and date in plain English. It reads your Garmin history, builds the marathon block around your actual fitness, and pushes each session to the watch, reshuffling the week when you miss days or your recovery drops.
Want this marathon plan built for you?
Tell the coach your race and your date in plain English. It reads your Garmin, builds the week, and pushes every session to your watch.
Build my marathon planSet it up on your watch
- Forerunner 570 training plan
- Forerunner 955 training plan
- Forerunner 970 training plan
- Fenix 8 training plan
First one? The first marathon guide is built around finishing rather than racing.
Useful free tools: race time predictor · heart rate zone calculator · overtraining check.
FAQ
How long does it take to train for a marathon?
Sixteen to twenty weeks from a solid base of regular running. If you are not comfortably running four times a week already, build that first and then start the block.
How far should my longest run be before a marathon?
Usually 30 to 35 km. Running the full distance in training costs more recovery than it returns in fitness for most amateur runners.
How much should I eat during a marathon?
Most runners aim for 60 to 90 grams of carbohydrate an hour, and the gut has to be trained to handle it. Practise your exact race fuelling on long runs for months, not weeks.
Why do people hit the wall in a marathon?
Usually a combination of starting too fast and taking on too little fuel. Both are pacing and planning problems rather than fitness problems, which is why both are fixable.