Run a Half Marathon in 4 Weeks with This Plan

When your 13.1-mile race is a month away—but you haven’t exactly been “training”—this plan is perfect

Photo: Derek Call

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Of all the things we prepare for in training for a race—nutrition, routes, gear, cross-training—it is the things we don’t prepare for that make the biggest impression on us. Illness, injury, unexpected work stress, family emergency; all of these things can throw you off track. But it doesn’t mean you’re doomed for a sub-par race. That’s where the four-week half marathon training plan comes in.

Take Heather Colasuonno. She was in the best shape of her life while training for the Toronto Waterfront Half Marathon when she was sidelined by an Achilles tendon strain. The 30-year-old wife and mother from Ajax, Ontario, couldn’t run for more than a month and returned to the roads just six weeks before race day. Nevertheless, Colasuonno made the best of the training window she had left and ended up coming within seconds of matching her fastest half-marathon ever. She is proof that it is possible to crash train for a half marathon.

How Long to Train for a Half Marathon?

Thinking of pulling out of that race you paid for months ago? Provided you’re healthy and able to train without further interruptions, four to eight weeks is enough time to “crash train” your way to a successful 13.1-miler. This assumes you were training appropriately before the interruption or that you were running enough miles a day to keep up your base fitness.

In general, runners should allow 12 weeks to prepare for a half if they’re already running and 18 weeks if they haven’t, with a minimum of three runs per week and ideally four or more.

So if you’re new to running, head over to our couch to half marathon training plan for a 20-week plan that will help you prepare for the experience without risking injury.

Tips for Crash Training a Half Marathon

The key to crash training is building fitness quickly without taking big risks. The best tools for fast fitness are frequency and intensity. Doing some kind of cardio almost every day—whether that means running, walking, or cross-training—will help you make the most of the time you have. And a couple of those workouts each week should include high-intensity effort, which is proven to stimulate quicker physiological adaptations.

To summarize, here’s what you should be doing during your one-month half marathon training plan.

  • Do some form of cardio daily
  • Daily cardio can include walking, cross-training, or running
  • Ensure a few cardio workouts are at a high-intensity effort weekly

Training Schedule for a Half Marathon

This training plan for a half marathon in 4 weeks is perfect if your goal is to walk or walk/run a half marathon that is four weeks away, and you’re currently fit enough to comfortably walk/run 5 miles. The table below shows what a typical week looks like. You’ll do faster interval runs on Tuesday and Friday to build fitness quickly, a long run on Sunday to build the endurance you need to go the distance, and rest on Monday.

Monday Tuesday Wednesday Thursday Friday Saturday Sunday
Rest Interval run Optional walk, run, or cross-training Walk Interval run Optional walk, run, or cross-training Long run

Wednesday and Saturday are “optional” days, where you have a choice to rest, walk, run, or cross-train with non-impact cardio, such as cycling or elliptical training. You’ll get fitter faster if you choose the rest option only when you feel your body needs it.

Each run uses a five-point intensity scale based on ratings of perceived effort (RPE). Heart-rate monitors can be helpful, but going by feel works just as well. Use these guidelines to understand your plan’s intensity scale.

  • RPE 1: Very Easy—a pleasant effort you feel you could keep up almost indefinitely
  • RPE 2: Comfortable—you’re not holding yourself back but you can still easily carry on a conversation
  • RPE 3: Comfortably Hard—the highest intensity at which you can speak comfortably
  • RPE 4: Hard—after a few minutes at this intensity, your breathing is labored
  • RPE 5: Very Hard—an effort that you can sustain for a couple of minutes at most

In interval walk/run workouts, walk the RPE 1 portions if necessary to keep your perceived effort at an appropriate level. In long run/walk workouts, mix walking and running as you see fit or as necessary to keep your RPE between 1 and 2.

How to Train for a Half Marathon in 1 Month Safely

Two big risks are associated with crash training for a half marathon in four weeks: injury and overreaching (where too much training and too little rest lead to excessive fatigue).

To minimize the risk of injury, incorporate non-impact cardio cross-training into your training schedule. By challenging your aerobic system without the repetitive impact associated with running, activities like cycling and elliptical training help runners build fitness faster without increased injury risk.

A study by scientists at Purdue University found that runners who increased their training load for six weeks with bicycling improved their 5K times as much as runners who added a commensurate amount of running.

The best way to avoid overreaching is to listen to your body and rest when needed, regardless of what’s on your training schedule. After each run, rate it as “good” if you felt better than normal, “average” if you felt normal, and “poor” if you felt worse than normal. Take a day off if you rate two consecutive runs as “poor.”

4-Week Half Marathon Training Schedule

Week 1

Day Workout
Monday Rest
Tuesday Interval run/walk:
5 min @ RPE 1 +
5 min @ RPE 2 +
3 x (1 min @ RPE 5/2 min @ RPE 1) +
5 min @ RPE 2 + 5 min @ RPE 1
Wednesday Optional walk, run, or cross train 30 min @ RPE 1–2 or Rest
Thursday Walk: 60 min @ RPE 1–2
Friday Interval run/walk:
5 min @ RPE 1 +
5 min @ RPE 2 +
4 x (1 min @ RPE 5/2 min @ RPE 1) +
5 min @ RPE 2 +
5 min @ RPE 1
Saturday Optional walk, run, or cross train: 30 min @ RPE 1–2 or Rest
Sunday Long run/walk: 5 miles @ RPE 1–2

Week 2

Day Workout
Monday Rest
Tuesday Interval run/walk:
5 min @ RPE 1 +
5 min @ RPE 2 +
5 x (1 min @ RPE 5/2 min @ RPE 1) +
5 min @ RPE 2 +
5 min @ RPE 1
Wednesday Optional walk, run, or cross train: 35 min @ RPE 1–2 or Rest
Thursday Walk: 65 min @ RPE 1–2
Friday Interval run/walk:
5 min @ RPE 1 +
5 min @ RPE 2 +
6 x (1 min @ RPE 5/2 min @ RPE 1) +
5 min @ RPE 2 +
5 min @ RPE 1
Saturday Optional walk, run, or cross train 35 min @ RPE 1–2 or Rest
Sunday Long run/walk: 7 miles @ RPE 1–2

Week 3

Day Workout
Monday Rest
Tuesday Interval run/walk:
5 min @ RPE 1 +
5 min @ RPE 2 +
7 x (1 min @ RPE 5/2 min @ RPE 1) +
5 min @ RPE 2 +
5 min @ RPE 1
Wednesday Optional walk, run, or cross train 40 min @ RPE 1–2 or Rest
Thursday Walk: 70 min @ RPE 1–2
Friday Interval run/walk:
5 min @ RPE 1 +
5 min @ RPE 2 +
8 x (1 min @ RPE 5/2 min @ RPE 1) +
5 min @ RPE 2 +
5 min @ RPE 1
Saturday Optional walk, run, or cross train 40 min @ RPE 1–2 or Rest
Sunday Long run/walk: 9 miles @ RPE 1–2

Week 4

Day Workout
Monday Rest
Tuesday Interval run/walk:
5 min @ RPE 1 +
5 min @ RPE 2 +
4 x (1 min @ RPE 4/2 min @ RPE 1) +
5 min @ RPE 2 +
5 min @ RPE 1
Wednesday Optional walk, run, or cross train 45 min @ RPE 1–2 or Rest
Thursday Walk 60 min @ RPE 1–2
Friday Interval run/walk
5 min @ RPE 1 +
5 min @ RPE 2 +
3 x (1 min @ RPE 5/2 min @ RPE 1) +
5 min @ RPE 2 +
5 min @ RPE 1
Saturday Rest
Sunday Race Day Half Marathon

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