Heart Rate Variability

What is heart rate variability?

Heart rate variability (HRV) is the variance in time of the intervals between successive heart beats, typically measured in milliseconds.

HRV is closely linked to the autonomic nervous system (ANS) activity and is commonly used as a measurement of the activity in this system.

The ANS is divided into two systems, the sympathetic and parasympathetic nervous systems. Through various statistical measures (time and frequency based), HRV allows us to gain insight into the workings of the ANS.

What affects HRV?

A range of physiological phenomena affect HRV including:

  • Respiration
  • Body temperature
  • Exercise and aerobic health
  • Age
  • Gender
  • Circadian rhythm
  • Diet and hydration
  • Emotions

Why is HRV important?

HRV is a powerful tool for analysing cardiac and physical health. Access to more HRV data allows clinicians to gain greater insights and make more informed medical decisions about your health.

By measuring HRV over time, individuals can gather information about how they are responding to everyday situations.

HRV has also been linked to several health conditions including diabetes, autoimmune disorders, and cardiorespiratory conditions. Furthermore, there is strong evidence tracking HRV can be used as an indicator of mortality.

HRV is also a key input into many advanced algorithms including Stress.

Stress is a loosely defined term with many different interpretations, however B-Secur defines stress as a physiological response to an internal or external stimulus. This stimulus can be physical, emotional, societal, or psychological.


HeartKey® Heart Rate Variability algorithm complies with the medical ANSI EC57 standard. The performance validation is available under NDA.

Understanding Heart Rate Variability: Why Does It Matter?

Find out more about how HeartKey® can use heart rate variability data to provide insights about stress, recovery, and exercise.

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