Heart rate variability (HRV) is simply the variation in time between each consecutive heart beat in milliseconds. It is controlled by the autonomic nervous system (ANS) and its branches – the sympathetic and parasympathetic nervous systems.
The sympathetic system (fight or flight system) increases our hearts’ contraction rates resulting in reduced hrv while the parasympathetic nervous system, using the vagus nerve, slows down the heart rate leading to high hrv.
HRV is also affected by physical activity, physical or mental stress, respiratory sinus arrhythmia (your respiration), reflexes (baroreflexes, chemoreflexes etc) and cardiovascular diseases like myocardial infarction and congestive heart failure that cause mortality.
Analysis of heart rate variability
The Task Force of the European Society of Cardiology came up with standards of measurements for HRV after discovering its great potential.
One result is that HRV measurements are now usually taken y a device called an electrocardiogram (ECG or EKG). For the HRV analysis to be successful, the device has to accurately measure the time interval between each ‘heartbeat wave’ (QRS complex), otherwise known as the r-r interval and eliminate all abnormal heart beats not generated by the sinoatrial node
The spectral analysis of acquired hrv data is done using time domain analysis or frequency domain analysis. The time domain method is the most popular in clinical use as it is not as sensitive to noise.
Some of the variables that the time domain measures are:
- Mean normal-normal interval (NN)
- SDNN (standard deviation of NN intervals)
- rMSSD (root of mean squared successive difference in nn intervals)
Some frequency domain variables to obtain the power spectrum for oth short-term and long-term recordings are:
- Total power (variance of all nn intervals)
- VLF (power in the very low frequency range)
- HF (power in the high frequency range)
- LF (power in the low frequency range)
- LF/HF ratio
Wearables that measure the inter-beat intervals in blood signals have also been designed to take HRV measurements.
Why Measure Heart Rate Variability
HRV can be used to assess autonomic function and to make sure you have a healthy heart and a healthy cardiovascular system in general. Healthy individuals usually have a low resting heart rate and higher hrv.
This is because a high hrv means that the body responds well to inputs caused by both efferent sympathetic and parasympathetic activity. Low hrv however means that one system is exerting more dominance leading to an imbalance. It has been linked to sudden cardiac death, blood pressure, stress and overtraining.
Due to this, measuring heart rate ariality can be used to get insight on stress levels, exercise limits and your overall well-being. If you’re a healthy subject, you’ll have a lesser risk of heart diseases like heart attacks.
How To Increase HRV
You can increase your hrv by improving the balance between your sympathetic and parasympathetic nervous system. Our Apollo device has been scientifically proven to emit vibration patterns that allow the body to regain that balance and remain calm under pressure. Get your Apollo today for a healthier lifestyle!