How to use your lactate threshold for a faster race pace

Use your lactate threshold as a guide for smarter training and soon enough you’ll have it in your arsenal for smarter racing

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Setting a steady effort for your race can result in faster times and a much more predictable performance. For many of us athletes whose goal is to have a great time racing, the biggest benefit of proper pacing is ensuring an enjoyable experience from start to finish. Here’s how you can save yourself from race day disaster and bag a fast finish.

Follow your heart

Heart rate training zones are one of the most commonly used and carefully studied methods in pacing for triathlon. A percentage of your lactate threshold heart rate (LTHR) is targeted, a number that depends on your race distance. To get your LTHR, Joe Friel recommends a 30-minute test:

  • Run or bike on your own at a steady effort level you can maintain for 30 minutes with a heart rate monitor. Your heart rate may vary across the two disciplines and so the exercise should be completed in both sports.
  • Take your average heart rate during the last 20 minutes of your effort and set this to approximate your LTHR. A steady effort should be taken for the full 30 minutes, despite the first 10 minutes not being measured.
  • Set the following zones as a percentage of your LTHR:
    • Zone 1: < 85 percent
    • Zone 2: 85 to 89 percent
    • Zone 3: 90 to 94 percent
    • Zone 4: 95 to 99 percent
    • Zone 5: 100 percent

As your conditioning improves, your LTHR will not typically vary greatly, but the speed you are able to attain at the same heart rate will.

Throughout your lactate threshold test, your heart rate should be increasing over time
Throughout your LTHR test, your heart rate should be increasing over time. It’s important to keep a steady effort throughout the 30-minute test

Measure your distance

Your LTHR zones say a lot about what your body is doing at a current level of effort, and how sustainable that pace is. Higher zones are tougher to maintain and are typically reserved for short courses. Below is a cursory guide for setting your pace depending on race distance:

  • Sprint – High zone 4 to low zone 5
  • Olympic – Zone 4
  • Half-Ironman – Zone 3 to 4
  • Ironman – Zone 2 to 3

It should be said that for beginners, targeting LTHR can be misleading. Slower athletes may be forced to race at a target zone for too long, putting an amount of stress that cannot be maintained for an extended period. Race conservatively and target the low end of the target LTHR on your first attempt.

Exceptions to the rule

Your race lactate threshold heart rate should be a target to strive for throughout the race but because of significant events in a triathlon, there are exceptions when going after a personal best:

Keep up in the swim

A draft advantage may mean occasionally speeding up past a comfortable pace so you don’t get left behind.

Your body is in transition, too

After the swim, your heart rate is typically higher than desired. For longer courses, many athletes let their heart rates settle for the first few minutes before hitting race pace on the bike.

At the end of your run

Closer to the finish line, the risk of blowing up decreases as there is a shorter distance to cover, and the sustainability of your effort becomes less important. “Negative splits” are encouraged, where you target higher and higher heart rates as you get closer to the finish line.

On your next track day or ride out, take that heart rate monitor with you and complete your threshold test. Use it as a guide for smarter training and soon enough you’ll have it in your arsenal for smarter racing.

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