Threshold heart rate is the highest heart rate you can hold for about one hour of hard, steady effort.

It sits between comfortable and all out. You are working hard, but in control.

This point matters because it reflects how much work your body can sustain aerobically. Training zones built from threshold are far more accurate than zones based on maximum heart rate or age formulas.

As fitness improves, threshold usually increases. That is why zones should be updated over time.

Threshold pace or power is the fastest pace or highest power you can sustain for about one hour.

For runners, this is your threshold pace.
For cyclists, this is your threshold power.

It represents your sustainable performance level, not a sprint and not a guess.

Using threshold pace or power allows training to stay consistent across terrain, weather, and fatigue. Hills, heat, and wind change speed, but effort stays the same.

That is why threshold based zones are used by coaches and labs. They anchor training to what your body can actually handle, not what looks good on paper.

There are two reliable ways to do this.

1. Field testing
This is the most accessible option.

Run or ride a hard 20 minute time trial. Warm up properly, then go as hard as you can sustain for 20 minutes.

Take 95 percent of your average heart rate, pace, or power from the effort. That number is your estimated threshold.

Examples

• If your average heart rate was 185, enter 176 (95 percent of 185) into the calculator.
• If your average pace was 4:00 per km, your threshold pace would be approximately 4:12 per km.
• If your average power was 300 watts, your threshold power would be 285 watts.
  

Field tests are not perfect, but they are practical, repeatable, and good enough for most athletes.

Lactate Testing
This is the gold standard.

Lactate testing measures how your body responds to increasing intensity and identifies your true physiological threshold. It removes guesswork and gives precise heart rate, pace, or power values.

This is the most accurate way to set training zones, especially if you want confidence that every session is targeted correctly.

Whichever method you use, the key is consistency. Use the same approach each time and update your zones as fitness changes.

Use both. Heart rate responds to fatigue and conditions. Pace is stable and simple.

We recommend using heart rate for your aerobic training, and pace for tempo, high-intensity, and race-specific training.

Yes. As fitness improves, threshold usually increases. Recalculate your zones every few months or when your zones not longer match your perceived effort.

Yes. Zones are especially helpful early on because they prevent training too hard too often.