Heart rate variability

Heart rate variability (HRV) refers to the change of the difference in the heartbeat cycle from time to time. It contains information on the regulation of the cardiovascular system by neurohumoral factors, so as to determine its condition and prevention of cardiovascular diseases. It may be a prediction of sudden cardiac death and heart rhythm. A valuable indicator of abnormal events. In layman's terms, heart rate variability (HRV) refers to the change of the heartbeat cycle difference or the change of the heartbeat rate. It is determined by the length of the two adjacent RR intervals, that is, from the first heartbeat. The small difference between the cycle and the next cardiac cycle.

By testing various indicators of individual heart rate variability, it can provide information about the autonomic nervous system, stress state, etc., and provide clues and basis for guiding clinical and scientific research.

Autonomic nervous system

(1) Autonomic nervous system activity

The total energy (TP) in the frequency domain index has a similar representative meaning to the SDNN parameter in the time domain index. Reflects the overall activity of the autonomic nervous system, which can be used to assess the regulatory capacity of the autonomic nervous system

For example: in the case of chronic stress or disease, the adjustment ability of the autonomic nervous system is reduced, and TP is significantly reduced.

(2) Autonomic nervous system balance

The LF/HF in the frequency domain index reflects the relative activity of sympathetic nerves and parasympathetic nerves.

For example: Sympathetic nerve (SNS) strength: It indicates that the body is in a state of anxiety, fear, irritability, loose attention, and hypervigilance; Parasympathetic nerve (PNS) strength: It may indicate muscle weakness, chronic neurasthenia, depression, etc.

(3) Autonomic nervous system stability

Generally, the stability of the ANS system is reflected by the strength of the LF and HF components. When the individual is under chronic stress or disease state, both LF and HF intensity show a decline.


Appropriate pressure will be the catalyst for life, but excessive pressure will endanger human health.

(1) Compressive ability

The SDNN parameters in the commonly used time domain indicators reflect that the SDNN value decreases, indicating that the complexity of heart rate variability is reduced, and the body's ability to adapt to environmental changes is weakened.

(2) Fatigue

The analysis of fatigue degree usually adopts the two parameters of TP and LF in the frequency domain index, combined with the pressure degree for comprehensive evaluation. Generally speaking, the greater the pressure, the greater the degree of fatigue, and the patient is prone to symptoms such as fatigue and muscle weakness. At this time, the TP and LF values all appear to decrease.

Simply put, the higher the heart rate variability, the faster the heart can adapt to internal and external influences, that is, the better the body's adaptability to environmental changes. On the contrary, it indicates that the body's ability to adapt to the environment is worse, and may imply serious health damage. For example: cardiovascular disease, mental illness, neuropathy or cancer, etc.