Major Calorie Bug - 9 Peak Pro - Post-Jan 2026 Update

[vladutz]

I’m reporting a severe regression in calorie tracking for the “Weight training” profile on the Suunto 9 Peak Pro.

The issue: Since the last january update (two weeks ago), the watch seems to count calories only during active movement, completely ignoring heart rate data during rest intervals.

The proof of the bug:
In a 60-minute weight training session (Avg HR ~100 bpm, with peaks up to 125 bpm), the watch recorded only approx. 50 kcal.

This is a clear logic error: my Basal Metabolic Rate (BMR) — the energy my body burns just by existing — is higher than that. The watch is recording fewer calories than if I were doing nothing at all. Before the update, the same intensity would correctly yield around 250-350 kcal.

Key observations:
• Calories seems to “freeze” the moment I stop moving between sets, even if my HR remains elevated.
• The algorithm now seems to over-prioritize the accelerometer over HR data, which doesn’t work for weightlifting where movement is intermittent.

Is anyone else seeing these “flat” calorie readings during gym sessions?