Lactate threshold heart rate — the heart rate at the highest intensity you can sustain for roughly an hour. It's the anchor for heart-rate training zones, and you estimate it from the last 20 minutes of a 30-minute time trial.

Why use the last 20 minutes for LTHR?

Heart rate takes several minutes to rise to steady state, so the first 10 minutes of the test sit below your true threshold. Averaging only the final 20 minutes gives a more accurate LTHR.

Is threshold pace the same as race pace?

For trained runners it's close to one-hour (roughly 10-mile to half-marathon) race pace. It's faster than marathon pace and slower than 5K pace.

How often should I test threshold?

Every 4–6 weeks during a training block, under similar conditions. If you use Stride, it re-estimates threshold continuously from your runs, so dedicated tests become optional.

Training Guides·Updated 23 Jun 2026

How to Find Your Threshold Pace and Heart Rate

To find your threshold heart rate and pace, run a 30-minute solo time trial at the hardest pace you can hold evenly. Your average heart rate over the final 20 minutes is your threshold (lactate) heart rate, or LTHR; your average pace across the 30 minutes is your threshold pace. Both anchor your training zones — or let Stride estimate them from your normal runs.

Quick answer

Run a 30-minute all-out solo time trial. LTHR = average HR of the last 20 minutes. Threshold pace = average pace over the 30 minutes. Re-test every 4–6 weeks.

The 30-minute threshold test#

Warm up well, then run 30 minutes alone (no drafting, no group) on flat ground or a track at the hardest pace you can sustain evenly to the end. Start controlled — most people go out too fast — and press the lap button at 10 minutes so you can read the final 20 minutes separately.

Your threshold heart rate (LTHR)#

Take your average heart rate over the last 20 minutes of the test — that's your LTHR. Using the final 20 minutes avoids the early portion where heart rate is still climbing toward steady state, giving a truer threshold value to build heart-rate zones from.

Your threshold pace#

Your average pace across the full 30 minutes is a good estimate of threshold pace (close to your one-hour race pace for trained runners). Use it to set running pace zones and to anchor tempo and threshold workouts. Cyclists can find threshold heart rate the same way during an FTP test.

Or let Stride estimate it#

Maximal tests are hard to pace and stressful to repeat. Stride estimates your threshold pace and heart rate from your everyday runs and keeps your zones current automatically, so you can skip test day. Try Stride free.

FAQ#

Frequently asked questions

What is LTHR?: Lactate threshold heart rate — the heart rate at the highest intensity you can sustain for roughly an hour. It's the anchor for heart-rate training zones, and you estimate it from the last 20 minutes of a 30-minute time trial.
Why use the last 20 minutes for LTHR?: Heart rate takes several minutes to rise to steady state, so the first 10 minutes of the test sit below your true threshold. Averaging only the final 20 minutes gives a more accurate LTHR.
Is threshold pace the same as race pace?: For trained runners it's close to one-hour (roughly 10-mile to half-marathon) race pace. It's faster than marathon pace and slower than 5K pace.
How often should I test threshold?: Every 4–6 weeks during a training block, under similar conditions. If you use Stride, it re-estimates threshold continuously from your runs, so dedicated tests become optional.

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