How to Pace Your Fastest Half Marathon

Have you ever endured that moment in a race where suddenly your legs cannot run any faster? The sensation of defeat overwhelms you, as your pace slows down and the finish line is still miles away. Many runners are familiar with the crash-and-burn experience in the half marathon distance. They start out fast since they feel good, but then fall off pace with just a few miles to go.

You do not have to make that mistake! This articles shares an effective half marathon pacing strategy. This is a strategy I’ve used to coach hundreds of runners to PRs in the half marathon distance.

>>Read here if you are looking for an effective marathon pacing strategy!

Why Does Pacing Matter for the Half Marathon?

For most runners, half marathon pace is slightly slower than your second lactate threshold. If you pace a half marathon correctly, you delay the onset of fatigue. However, if you start too fast, you risk fatiguing sooner due to a cascade of metabolic processes.

When you run faster than your lactate threshold, you accumulate lactate at a much more rapid rate. Now, lactate isn’t the big bad we once believed; your body can actually shuttle it from the bloodstream to cells and use it for further energy production. However, a by-product of lactate production are hydrogen ions and other acidic metabolites. These cause a burning sensation in your muscles and resulting fatigue. Your breathing also increases, as you both attempt to consume more oxygen for energy and as your body regulates its acid-base balance.

Essentially, you fatigue at a much quicker rate when working above your lactate threshold than when you run even slightly lower intensities. A common mistake When you start out a half marathon too fast, you fatigue more rapidly than you would at goal pace or slightly slower. That’s why the last 3-5 miles of a half marathon feels so difficult when you do not pace appropriately. You sabotaged your race by starting out too fast.

A Mile-By-Mile Half Marathon Pacing Strategy

These tips are what I have found that worked for me in running my half marathons, including my PR of 1:34 (here’s how I took 12 minutes off my half marathon time).  I have used these strategies on hundreds of runners as I have coached them to half marathon PRs. Of course, every runner is different, but these strategies can help you master how to pace a half marathon.

Before the Race:

Warm up with 5-10 minutes of very easy running, three or four strides at race pace, and dynamic stretches. The warm-up elevates the temperature of your muscles, which allows greater force production. Additionally, a warm-up increases blood flow – thus increasing oxygen delivery to your working muscles. 

>>Related: What to Eat Before a Half Marathon

First 1-2 Miles (First 1-3 km)

Take these miles steady and slightly controlled. You are tapered, so that will equate to a pretty quick pace. Even if you warmed up before the race, you do not want to jump right into goal pace just yet. Aim for 10-15 seconds slower than your goal pace.

Do not weave around other runners. The lateral movements will fatigue muscles you don’t normally use in running. Additionally, weaving will add extra distance to your race and affect your finish time. Let people pass you in that first mile.

Miles 3-9 (Km 4-15):

Settle into race pace. You should have practiced your half marathon pace enough in training where you know how this pace will feel on race day. The effort should feel moderate to moderately hard and relatively sustainable. Don’t obsess over your watch. Check in at your pace but trust yourself and trust your training.

Take most of your fuel in these early miles. Early carbohydrate intake improves your fatigue resistance. Additionally, your breathing rate is a bit lower in the early miles, which makes it easier to eat your gels or chews.

If you feel tempted to slow down or speed up too much at any point, focus on a few runners around you who are running your speed and pace with them. Pacing with others makes it easier to run faster than you would on your own. Take advantage of this effect if you find others running your goal pace.

Miles 10-12 (Km 16-19)

A half marathon will get hard at this point. However, a smart half marathon pacing strategy will set you up for success in the final 5K.

Aim to your goal pace as best as you can. If you feel good, try to increase your pace by 5-10 seconds per mile. If you are able to speed up, do not increase pace rapidly, as this costs more energy than a more gradual acceleration. 

This is when the race becomes a mental game. You will feel physically uncomfortable. You will be tempted to slow down. However, with the proper coping strategies you can sustain your pace.

Miles 13-13.1 (Final 2.1 km)

Once you start the final mile, you can push more – after all, you are almost done! If you have managed nutrition and pacing well, you are not about to crash and burn at this point (unless it is psychological).

This segment of the race is when you should try to pass other runners. Focus on one runner, work towards passing them, and then repeat. Passing will distract you from the discomfort. The accompanying surges that come with passing temporarily use a different energy pathway, so they are possible even when you are tired. 

Once the finish line enters your sight, you want to empty the tank. Cue yourself to increase your cadence to assist with a final sprint to the finish line.

Half Marathon Pacing Chart

This half marathon pacing chart is your cheatsheet for the above half marathon pacing strategy. Save this for future races!

This article has an extensive half marathon pace chart, from 1:00:00 to 3:30:00 finish times.

Half Marathon Pace FAQs

How do you pace your first half marathon?

Your pacing strategy for your first half marathon depends on your background. If this is your first race, you will want to treat it as a long run—comfortable and controlled. If you did not cover 11 or more miles in training, you do not want to try to push the pace. If you have lots of experience racing shorter distances, you might aim for a time goal.

Any special tips for how to pace a sub 2 hour half marathon?

A sub 2 hour half marathon is one of the most popular goals. Because of this, the race can be congested around the sub 2 hour half marathon pacer. You may want to account for this congestion and plan your pacing as if you were doing 13.2 or 13.3 miles in 1:59:59 or faster (which means a slightly faster goal pace).

>>Learn more: how to run a sub 2 hour half marathon!

Should you run with a pacer?

Many races provide pacers around common finish times (usually in 5 or 10 minute increments). Some pacers are very skilled and will consistently run the goal pace the other race. However, there is no guarantee. For example, when I ran a 1:39:04 half marathon (and consistently ran 7:30-7:35/mile splits the whole race), I was passed by the 1:50 pacer in the first 4 miles.

As a running coach, I encourage athletes who are considering using a pacer to talk with the pacer before the race. Ask them their strategy – will they run even splits or negative splits? Talk to them about how they adjust for hills or what they do if an athlete slows down.

Extra Tips on Half Marathon Pacing Strategy

• Focus on the mile you are in. Don’t worry about how you will feel in the next mile or at the end of the race.
• Don’t stare at your GPS instant pace (trees and skyscrapers can throw it off). Instead, set your watch to show lap pace (not instant pace). Check in on your mile or km laps to determine if you are running on pace.
• Bad miles and good miles both occur in a race. Don’t stress over a mile split that is too fast or too slow – simply get back to goal pace and focus on the next mile.
• Make sure you have a solid nutrition plan for your half marathon to support the energy pathways needed to finish strong!

Want more half marathon advice?

• How to Avoid Slowing Down During a Half Marathon
• How to Taper for a Half Marathon
• Your Guide to Half Marathon Recovery
• Effective Half Marathon Workouts