How Ascend Training Zones Work (And Why They Might Differ From Other Apps)

One of the most common questions we receive from new users is:

“Why don’t my training zones in Ascend match the zones in Strava, Garmin, or other platforms?”

The short answer is that training zones are not universal. Different platforms define training zones using different physiological models.

Ascend’s zones are based on the intensity framework developed by Olympiatoppen (the Norwegian Olympic Training Center), widely used by Norwegian endurance athletes and coaches.

Why Ascend Uses Threshold

In Ascend, your training zones are calculated from your lactate threshold (LT2).

This is the highest intensity you can typically sustain for about 30–60 minutes during a race or hard effort.

Physiologically, LT2 represents the point where lactate production begins to exceed the body’s ability to clear it, causing fatigue to accumulate rapidly. Efforts above this intensity quickly become difficult to sustain for long periods.

We anchor the zone system to threshold (LT2) for two main reasons.

1. It reflects individual fitness

   
   

Threshold varies significantly between athletes and changes as fitness improves. Two runners with the same maximum heart rate can have very different threshold intensities depending on their aerobic development.

Because of this, estimating zones purely from % of max heart rate often introduces large errors. A threshold-based approach adjusts the entire zone system to the athlete’s current fitness.

2. It is relatively easy to estimate

   
   

Threshold can be estimated reasonably well from real-world performance data, such as:

• a recent 10k race

• a 30-50 minute all-out, solo effort

• a 30-50 minute interval workout

• a lab test

  
  

These estimates tend to be more reliable than trying to determine true maximum heart rate, which requires maximal efforts and can vary significantly between tests.

Because of this, threshold remains the most practical anchor for estimating training zones.

Once threshold pace and heart rate are known, Ascend can estimate the surrounding intensity ranges and provide guidance across the full spectrum of training intensities.

The Ascend Zone System

The Ascend zone system is derived from a 5-zone physiological model, anchored by your threshold (LT2) values. Below you’ll find an overview of the zone system used, and how it relates to your threshold pace and heart rate.

Refer to the in-app intensity guidance for each individual workout for personalised intensity guidance unique to your threshold values. You’ll also find further information about the intensity zones under the Guidance tab in the app.

*may not be achieved during initial phases of effort.    

**Cannot be measured accurately due to the short nature of these efforts and the time it takes to get suitable readings to monitor intensity..

***This is highly individual and sport-specific. It requires sufficient experience to use blood lactate as a valid measure of intensity.

*LT1 (Lactate Threshold 1) is the first physiological breakpoint during increasing exercise intensity, where blood lactate begins to rise slightly above resting levels but can still be cleared efficiently. Conversation is still possible, but slightly less relaxed.

Why Your Zones May Look Different From Other Apps

Different platforms calculate zones using different methods.

Some use:

• percentage of maximum heart rate

• heart rate reserve

• proprietary algorithms

• race-derived pace models

  
  

Because of this, the same zone number can represent different intensities across platforms.

For example, an easy run might appear as:

• Zone 2 in Garmin

• Zone 1–2 in Ascend

• Zone 3 in another system

  
  

This doesn’t mean something is wrong, it simply reflects different intensity models.

Follow the Zone Guidance Within Ascend

Because different platforms define zones differently, Zone 3 in Ascend does not necessarily represent the same intensity as Zone 3 in other places.

For this reason, when following workouts in Ascend it’s important to follow the zone guidance provided in the app rather than trying to match zones from other platforms.

All workouts, analysis, and training load metrics in Ascend are built around our threshold-based zone system. As long as your threshold values are set correctly, the training guidance will work as intended.

Mixing zone definitions between platforms can make workouts feel either too hard or too easy, which may reduce the effectiveness of your training.

The simplest approach is to treat Ascend as your reference system when following your training plan.

The Takeaway

Ascend’s training zones are built around lactate threshold (LT2) using the intensity framework developed by Olympiatoppen.

Because different platforms define zones differently, the exact zone numbers may not always match what you see elsewhere. What matters is following the zone system and intensity guidance within Ascend, since all workouts and training insights are based on that model.

Learn more about Ascend