Emotions are more than just feelings—they have measurable patterns in your body. We use insights from the valence-arousal model of emotion to help you better understand how your nervous system responds to stress and stimulation. One of the ways we do this is through a unique metric called Stress Intensity (SI).
The Valence-Arousal Model
Emotions are mapped across two axis:
- Valence (X axis): How pleasant or unpleasant an emotion feels.
- Arousal (Y axis): How activated or energized your body is, regardless of whether the emotion is positive or negative.
Excitement and anxiety, for example, are both high-arousal states—but they differ in valence. Calm or sadness, on the other hand, are low-arousal states.
What Is Stress Intensity (SI)?
Stress Intensity (SI) is our interpretation of the arousal axis from the valence-arousal model. It measures how activated your nervous system is in the moment—based on physiological signals like heart rate variability and RR intervals.
What does this mean?
High SI doesn’t always mean “bad stress,” but it does indicate that your body is in a heightened state of alertness or stimulation. It’s your system saying: Something’s happening.
Low SI, on the other hand, reflects a calmer, more relaxed physiological state.
Why SI Matters
Track your triggers
SI helps you identify moments when your body is under pressure—even if your mind hasn’t caught up yet.
Build emotional awareness
Build emotional awareness: Learn to spot when your arousal level rises, and how it affects your thoughts and behavior.
Balance with EPI
SI pairs beautifully with your Evolve Power Index (EPI). While EPI reflects heart coherence, SI gives you a window into your body’s activation level. Together, they paint a fuller picture of your inner state.