Why is my heart rate target the same (or nearly the same) for different pace steps?

It can be confusing to see a workout — like a Progression Run — where the target pace increases at every step while the heart rate target remains (nearly) identical. While it looks like a glitch, it is actually a result of the AI’s rigorous analysis of your data.

1. The Goal: Finding Your 'Sweet Spot'

TrainAsONE constantly seeks the 'Sweet Spot' — the optimal combination of pace and heart rate that delivers the maximum physiological benefit with the minimum amount of unnecessary strain. If the system believes a specific heart rate range is your ideal 'operating window' for the entire session, it will keep it steady while using pace to drive the workload.

2. The Technical Reason: 'Flat Regression'

The AI builds your targets by looking at your historical data. If the system observes a Flat Regression, it means that in your recent runs, changes in your pace resulted in very little detectable change in your heart rate.

Because your heart rate is barely moving relative to your speed in that specific intensity zone, the AI cannot confidently prescribe a different HR for each step. Instead, it provides:

• Variable Pace Targets to ensure you are hitting the intended intensity.

• A Constant Heart Rate Range to act as a safe 'ceiling' for that effort.

3. Handling Data Noise

Human physiology is volatile. Factors like heat, caffeine, stress, or even a loose heart rate strap can create 'noisy' data. If the data is too scattered for the AI to find a clear, linear relationship between a specific pace and a specific heart rate, it defaults to a proven, safe range rather than 'guessing' at targets it can't mathematically justify.

4. How to Run These Sessions

If you see a flat heart rate target across multiple pace steps, follow this simple strategy:

• Prioritise the Pace: Focus on hitting the speed targets for each step. This ensures you get the intended training stimulus.

• Use HR as a Ceiling: Treat the heart rate range as a safety buffer. As long as you stay within that broad range, the workout is a success.

• Manual Refinement: If you prefer a 'stepped' feel, you can aim for the lower end of the HR range for the first step and gradually move toward the upper end as the pace increases.

The Evolution of Your Plan: As you record more 'clean' data and your fitness profile matures, TrainAsONE will continue to refine these relationships. Over time, as the AI gains higher confidence in your cardiovascular 'fingerprint', it will begin to prescribe more granular, stepped heart rate targets.