Heart rate variability (HRV) is the physiological phenomenon of variation in the time interval between heartbeats. Every time your heart beats, there’s a small variation in the time elapsed from its last beat. If your average heart beat is 60 beats per minute (bpm), it may fluctuate between 50 and 70 bpm at any given moment. The greater the amplitude, the higher your HRV will be. This fluctuation of heart rate is controlled by the Autonomic Nervous System (ANS), which stimulates or inhibits various body systems (i.e. perspiration, digestion, respiration, immune system functioning) depending on the perceived demands of a given situation.

There are two branches of the ANS:

Sympathetic Nervous System (SNS) - Speeds up the heart rate, prepares body for Fight or Flight.

Parasympathetic Nervous System (PNS) - Slows down the heart rate, prepares body to rest or digest.

The physiological processes unfolding in the ANS and heart have a strong relationship with different components of our experience, often directly affecting our emotional state, thought patterns, physical sensations, and behavioral tendencies. When we perceive a stressor our bodies react as though there is an immediate danger or threat, and the sympathetic (Fight or Flight) response becomes dominant, which typically increases heart rate, and lowers HRV.

Using HRV as a biosignal, the balance between SNS and PNS can be measured and decisively optimized over time, which can increase personal flexibility, stability, and our resilience to the challenging situations in our lives.

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