Training plans
Half marathon training plan that adapts to your recovery
A good half marathon plan is a handful of rules applied patiently: build slowly, make the long run the backbone, keep most running easy, add one or two harder sessions, and arrive at the start fresh. Here they are with numbers for three levels, an example week and a way to set your paces. At the end: how Keho Coach adjusts the same rules when your sleep, HRV or training load call for it.
Short answer
Train for 10–16 weeks on 3–6 days a week, depending on your level. Add no more than 10% to your weekly distance at a time, with an easier week every fourth week. Grow the long run to about 17–24 km, keep roughly 80% of your running easy, add one or two quality sessions, and cut volume over the last two weeks. When sleep, HRV or how you feel says you are not recovering, run less. Don’t make up missed runs.
How long to train, and how many days a week
- Beginner (you can run 30–40 minutes without stopping): 12–16 weeks, 3–4 running days.
- Intermediate (you have raced before and run 25–40 km a week): 10–14 weeks, 4–5 days.
- Advanced (years of consistent training, 50 km a week or more): 10–12 weeks, 5–6 days.
If you can’t yet run 30 minutes in one go, train for a 5K first. If you have a heart condition or another health problem, or haven’t exercised in a long time, see a doctor before you start.
Weekly distance and the long run by level
| Level | Peak week | Longest run |
|---|---|---|
| Beginner | 30–40 km (19–25 mi) | 17 km (10.5 mi) |
| Intermediate | 50–60 km (31–37 mi) | 21 km (13 mi) |
| Advanced | 65–85 km (40–53 mi) | 24 km (15 mi) |
Start from what you run now. Add no more than 10% a week, drop to about three quarters every fourth week so the work sinks in, hold the peak for a week or two, then taper.
Grow the long run by 1–2 km at a time. It peaks about two weeks before race day and steps back in cutback weeks. The classic guideline keeps it under about 30% of the week and under two and a half hours. On three or four running days it will be a bigger share, often 40–50%, which is fine as long as the other runs stay short and easy. Run it at easy pace; in the last month, some long runs can finish with 3–5 km at half-marathon pace.
Easy running and quality sessions
About 80% of your running time should be easy: a pace at which you can speak in full sentences. Beginners need one quality session a week, intermediate runners one in the base phase and two from the build phase on, advanced runners two. Keep an easy day between hard days.
- Threshold (tempo): 20–30 minutes at a comfortably hard pace you could hold for about an hour, or 3–5 × 6–10 minutes with short jogs.
- Intervals: 5–6 × 1 km at 5K–10K race pace, 2 minutes jogging between.
- Hills: 6–10 × 60–90 seconds uphill at a strong effort.
- Half-marathon pace: 2–3 × 3 km at goal pace in the last 4–6 weeks.
- Strides: 4–8 × 20 seconds quick and relaxed after an easy run.
Order them by phase: strides and hills in the base, intervals and tempo in the build, half-marathon pace at the end.
Example week in the build phase
One example week about six weeks before the race, not a full plan.
| Day | Beginner (4 days) | Intermediate (5 days) | Advanced (6 days) |
|---|---|---|---|
| Mon | Rest | Rest | Rest |
| Tue | Easy 6 km (4 mi) + strides | Intervals: 5 × 1 km, 10 km (6 mi) in total | Intervals: 6 × 1 km at 10K pace, 12 km (7.5 mi) |
| Wed | Rest or cross-training | Easy 8 km (5 mi) | Medium-long easy 14 km (8.5 mi) |
| Thu | Tempo: 3 × 6 min at threshold, 7 km (4.5 mi) | Rest | Easy 8 km (5 mi) + strides |
| Fri | Rest | Tempo: 20 min at threshold, 8 km (5 mi) | Threshold: 2 × 4 km, 13 km (8 mi) |
| Sat | Easy 5 km (3 mi) | Easy 6 km (4 mi) + strides | Easy 6 km (4 mi) |
| Sun | Long run 13 km (8 mi) | Long run 16 km (10 mi) | Long run 20 km (12.5 mi) |
| Total | 31 km (19 mi) | 48 km (30 mi) | 73 km (45 mi) |
How to set your paces
Set paces from what you can run today, not the time you hope for: ideally a race you ran all out in the last six to eight weeks. Pete Riegel’s formula scales it to another distance: predicted time = known time × (new distance ÷ known distance)1.06. A 10K in 55:00 predicts about 2:01 for the half, assuming you have trained for the longer distance.
- Easy: conversational, typically 60–90 seconds per km (1½–2½ minutes per mile) slower than half-marathon pace.
- Threshold: what you could race for about an hour, a little faster than half-marathon pace.
- Intervals: your 5K to 10K race pace.
Without a recent race, run by heart rate: easy runs below roughly 75–80% of your maximum, threshold work around 85–90%. Formulas like 220 minus age can be off by ten beats or more, so use a maximum you have actually seen.
A sub-2-hour half marathon
Two hours means 5:41 per km (9:09 per mile). By the same formula you need about a 54-minute 10K or a 26-minute 5K today. If you are close, 12 weeks on four days, peaking around 40–50 km with a long run of 18–21 km and a weekly tempo at 5:25–5:30 per km, is a realistic route. If you are several minutes away, race for the finish first.
Taper and race week
Over the last two weeks, cut volume to about 75% and then 50% of your peak but keep some speed: 2–3 × 1 km at half-marathon pace early in race week. Sleep well, try nothing new, and run at most 15–20 easy minutes the day before. On race day, start at or slightly slower than goal pace and push only in the last 5 km.
When to change the plan
- Poor sleep: after one bad night, move the hard session a day. After several, make the next quality session an easy run.
- HRV and resting heart rate: one morning means little. If HRV sits clearly below your usual range, or resting heart rate above it, for several days, run easy or rest. How to read your HRV.
- Feeling unwell: with a fever, chest symptoms or aching muscles, don’t run. Come back with a few easy days.
- Niggles: pain that changes your stride or worsens during a run means stop. See a doctor or physio if it persists.
- Travel: after long flights, keep runs short and easy for a day or two.
- Missed runs: carry on from today. After a missed week, repeat the last full week.
The rule behind all of these: reduce, don’t make up. Squeezing missed kilometres into the next days adds load exactly when you are least ready for it.
How Keho Coach builds and adapts your plan
- Choose your race and date, your level (New to running to Elite), how many days a week you run (1–7), which weekdays, and your long-run day.
- Keho sets your paces from a recent race or personal best in Apple Health, otherwise from its VO2max estimate, otherwise from heart rate alone. Easy runs follow heart rate, faster work follows pace.
- It builds every week with the rules above: the peak and longest run for your level, never more than 10% added in a week, a cutback every fourth week, the long run peaking two weeks out, a taper to 75% and then 50%.
- The next seven days of runs go to your Apple Watch through WorkoutKit, with heart-rate and pace alerts from your own zones. Completed runs are matched to the plan automatically.
Nothing changes on its own. Tell Keho you are not feeling 100% (feeling unwell, a niggle, travel) and the week adjusts, then ramps back. When several low-readiness mornings come with HRV below your usual or resting heart rate above it, when training load climbs too fast, or when you have missed several sessions, Keho offers options that only ever reduce load, always including “Keep as planned”. You decide. Week 1 of any plan is readable before you buy, and your health data stays on your iPhone.
Common questions
How many weeks do I need to train for a half marathon?
12–16 weeks as a beginner, 10–14 with some racing behind you. From a base of 40 km a week or more, 8–10 weeks can be enough.
What is a good half marathon training plan for beginners?
Three or four runs a week for 12–16 weeks: a long run growing to 16–17 km, one short tempo session, and easy runs. Walk breaks are fine; finishing comfortably is the goal.
What is an adaptive training plan?
One that eases off after poor sleep, low-recovery mornings or a missed week, instead of pushing on as printed. Going further? Read the marathon training plan.
Source: Riegel, P. S. (1981), “Athletic records and human endurance”, American Scientist 69(3). General information, not medical advice.