How to Bonk-Proof Your Running

Illustration: Shawn O'Keefe

Improving Your Bonk Point

Once you know your bonk point, you want to challenge it every seven to 14 days with a no-carb run lasting 80 to 90 percent of your bonk point. From a two-hour bonk-point example, you’d need to execute no-carb runs of 1 hour, 36 minutes (80 percent of the bonk point) to 1 hour, 48 minutes (90 percent). Aim to get several of these runs in during the final 12 to 16 weeks before your half marathon or marathon.

Note: You won’t fully bonk on these runs—you’ll get tired and signal your body and mind to quickly adapt to this type of running.

Because training should be aimed at improving your bonk point, you should retest your bonk point every four weeks or so to see if it has changed. I suspect you’ll see that your bonk point is farther out, meaning you’ll then need to extend the distance of your 80 to 90 percent, no-carb runs to reflect your increasing bonk point.

There are three other ways to bonk-proof yourself.

  1. Run more. Within your race-specific training phase (the last 10 weeks before your race), add another run to your weekly routine. You don’t have to do this every week but if your body is feeling OK, with no persistent aches or pains, add another easy 30- to 60-minute run to your week.
  2. Extend your average runs. If your runs typically average one hour, bump it up to 75 minutes. These additional 15 minutes help teach your body and mind that long-distance running is nothing to get worried about.
  3. Add a midweek long run. You’ll need to be smart about how this fits in with your other workouts, but a midweek long run of 90–105 minutes is a great way to build resistance to the bonk.
  4. Do more carb-free running. As with the bonk-point test run, work toward doing more of your running with no carbs. Fuel for your key workouts—but on regular runs, begin to run carb-free.


A big part of bonk-proofing yourself means lots of practice running at your goal race pace. Your body becomes more economical at the paces you run, so race pace training is a great way to bonk-proof. Racing too fast, too early is often the demise of runners.

Lastly, make sure you focus on the duration—not the speed—of your long, easy runs. While you will certainly want to do some race-specific long runs (fast finish or pace practice runs), it’s better for you to run longer and slower rather than shorter and faster.


Bonk-proofing works, but you need to be smart about implementing it.

  1. Always carry a rescue gel and fluids with you in case you really need it. Runners susceptible to hypoglycemia may want to skip this type of training.
  2. Run in areas where help is close by (and not a remote road or trail)—just in case you get woozy.
  3. Bonk-point test runs are hard on the body (and mind), so you need to plan extended recovery after them. I find that an additional two to three recovery days beyond my normal long run recovery is a good rule of thumb.
  4. Keep an eye on your musculoskeletal system and make sure your recovery isn’t only about feeling better mentally, but also being ready physically.
  5. This strategy is NOT for race day. I repeat: This strategy is NOT for race day.
  6. I highly recommend this strategy only for runners who have proven they can complete the distance and now want to finish faster.
  7. The limit on bonk-point runs is 3–3.5 hours. If you can run carb-free for three hours, it is unlikely (given a proper race strategy and race day fueling) that you will hit the wall in your next race.


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