Heartfy – Heart Rate Monitor

Response from developer

Thank you for sharing your thoughts! We’d love to explain in more detail how our Stress and Tension scores work: • Stress is based on HRV analysis, similar to the Baevsky Stress Index, which is a scientific method used to assess how much load your nervous system is experiencing. In simple terms: • High stress scores usually mean your body is working harder to stay balanced (lower HRV, higher strain). • Lower stress scores indicate your system is more relaxed and adaptive. This metric doesn’t just look at heart rate, but at the rhythm of your heartbeats and how your body reacts to internal and external demands. Tension reflects local muscle and vascular tone in the area where you measure. That’s why you may see a difference between left and right hand results - local circulation, muscle use, or even posture can influence it. For consistency, we recommend using the same hand each time.