Training for the Half Marathon

What the race demands

You race a half at an effort close to your lactate threshold — roughly the hardest pace you can hold for about an hour or more — for the whole distance. That makes your lactate threshold the master variable (see lactate threshold), sitting on a strong aerobic base and the endurance to hold that effort for 60–120+ minutes. Speed matters less than in the 5K/10K; sustainable strength matters more.

How to train for it

Build a solid aerobic base with mostly easy running, then make threshold the centerpiece of your quality work:

• Threshold / tempo runs and cruise intervals (see tempo & threshold runs) are the signature sessions — they raise the pace you can sustain, which is exactly what the half rewards.
• A weekly long run building toward roughly 90 minutes to two hours develops the endurance to hold effort late.
• Some faster intervals, especially earlier in the build, keep your VO₂max and economy sharp (see interval workouts).
• Goal-pace work as the race nears, so race pace feels familiar.
• If you'll be racing longer than about 90 minutes, practice fueling on your long runs (see carbs during exercise) rather than assuming you can run it dry.

How to periodize it

Base → a threshold-focused build → sharpening with goal-pace work, then a taper of roughly 7–14 days (commonly around 10) to arrive fresh — shorter than a marathon's (see periodization and tapering). The half responds well to consistent threshold training over a block of weeks.

Common mistakes

The usual half-marathon traps:

• Under-doing the long run, so the endurance to hold threshold effort for the back half isn't there.
• Racing every tempo run. Threshold work should be controlled and repeatable, not a max effort that leaves you wrecked.
• Skipping fueling practice because "it's only a half" — for anyone over ~90 minutes, a gel or two and some fluid matter.