Running a Half Marathon: Training, Times and Strategy for 21.1 km

What is a half marathon physiologically demanding?

You run a half marathon at 85à 92% of your VO2max, close to the lactate threshold but below it. That makes it an endurance and tempo race: you have to be able to run comfortably long enough to cover the distance without collapsing.

The primary limiting factor is the lactate threshold. The higher that threshold, the faster you can run a half marathon. In addition, running economy plays a significant role: small improvements in efficiency have a noticeable impact on the finishing time over 21 km.

Glycogen management starts to become relevant at the half marathon. Runners who run slower than 1h45 run long enough that their glycogen stores approach their limits. Fueling during the race then makes sense.

Typical times per level

Sub-2h00 for men and sub-2h15 for women is usually considered a serious recreational level. Sub-1h45 for men is a popular target for ambitious runners.

Training structure for a half marathon

How far in advance do you start?

For beginners who go from a basic condition to a first half: fourteen à eighteen weeks.

For runners who have already run a 10 km and now want to complete a half: twelve à fourteen weeks.

For experienced runners who want to get faster: ten à twelve weeks of focused preparation.

The core training for a half marathon

Tempo run (one and two times a week)

The most specific training for the half marathon. You train at or just below your lactate threshold, which for most runners is slightly slower than their half-marathon race pace.

Progression over the schedule: start with 20 à 25 minutes of tempo running and build up to 40 à 45 minutes. In peak weeks, a longer tempo run of 50à 60 minutes will be added.

Long endurance run (once a week)

The long run is more important for half marathon preparation than for the 5 km. It builds an aerobic base, improves fat burning and trains you for the duration of the effort.

Progression: start with 80à 90 minutes and build up to 110à 120 minutes in peak weeks. Do the longest long run two à three weeks before your competition.

Interval training (once a week)

Less central than 5 km training, but still valuable for VO2max and speed:

• 5 à 6 × 1000m at 5 km pace, with two minutes rest
• 4 × 1.5 km at 10 km pace, with two minutes rest
• 3 × 2 km at slightly faster than half marathon pace, with two minutes rest

Progressive long run

Once every two weeks: an endurance run that starts quietly in the first half and gradually builds up to half-marathon pace in the second half. Trains the specific effort distribution of the race.

Sample schedule for a half marathon (twelve weeks, five training sessions per week)

Half marathon race strategy

The start: the first seven kilometers are an investment

The most common half marathon mistake: starting at or faster than target pace while your legs are still fresh and the crowds are sucking you in. You pay the price between kilometers fourteen and twenty-one.

Run the first three à four kilometers deliberately five à ten seconds per kilometer slower than your target average.

Kilometer seven à fourteen: the core of the race

This is the longest segment and the most critical. You won't win a half marathon here, but you will lose it here. Keep your pace as steady as possible. Small fluctuations are normal, but large accelerations in this segment will be paid for later.

Kilometer fourteen à eighteen: the turning point

This is where the half marathon starts to separate. Those who have classified well feel that it is becoming more difficult but remains feasible. Those who started too quickly start to threaten here.

Mental tip: dividing helps. Not "seven more kilometers", but "two more blocks of three plus one last kilometer".

The last three kilometers

If you have done it right, an acceleration is possible. Not a sprint, but a conscious build-up. The real final sprint for the last 400m.

Fueling and hydration

During a half marathon, drinking is standard at every replenishment. For runners who run longer than 1h30: a gel or carbohydrate snack halfway (around km 9 and 10) and possibly a second one around km 16. Use what you tested during the training.

→ More about fueling on the go: nutrition while running.

Frequently asked questions

In summary

The half marathon requires a solid combination of tempo resistance (via tempo running), endurance (via the long endurance run) and a fair race strategy. Anyone who takes the first half calmly will still have something left in the tank in the last five kilometers. Those who don't do that will survive the last five kilometers.

→ Ready for the ultimate challenge? Read the marathon guide.
→ Everything about tapering in the weeks before your half: tapering for runners.