Heart rate variability, also known as HRV, is a metric that measure the fluctuations in time between individual heartbeats. Heart rate variability is an indicator of the state of the autonomic nervous system. The autonomic nervous system consist of the sympathetic nervous system and the parasympathetic nervous system.
The sympathetic nervous system manage the fight or flight response, and the parasympathetic nervous system manages the rest and digest functions. When the sympathetic nervous system and the parasympathetic nervous system is in balance, a person will have high heart rate variability. If a person is sick, stressed, or overtrained, the person will have low heart rate variability.
What is heart rate variability and how to improve it
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Low heart rate variability means that the heart rhythm is becoming more steady and robotic, and low heart rate variability indicates that the body is struggling to adapt to stress. Heart rate variability naturaly change as a person ages. A person will typically experience a decline in heart rate variability once a person pass there mid-twenties.
This decline in heart rate variability occurs because the biological machinery of the body change as a person ages. For example, arteries may lose elasticity, and hormonal profiles may shift. Additionally, the vagus nerve may lose some of it’s ability to regulate the heart rate.
Because the vagus nerve regulates the heart rate, a less responsive vagus nerve lead to lower heart rate variability. Gender also affect how heart rate variability changes over time. In younger years, women often have higher heart rate variability then men because estrogen has protective effects on the nervous system.
However, this difference in heart rate variability change during menopause because the levels of estrogen decrease. Eventually, men and women reach a similar baseline of heart rate variability when men and women reach their sixties. Thus, the biological differences in heart rate variability between men and women tend to converge as men and women age.
Physical activity can influence heart rate variability regardless of age. An athlete can maintain higher heart rate variability than a non-athlete of the same age. This is because high-intensity training and aerobic work help to train the nervous system.
Consistent aerobic work help the vagus nerve stay responsive, and a responsive vagus nerve leads to higher heart rate variability. Therefore, an athlete can use exercise to maintain a more higher level of heart rate variability. You can protect your heart rate variability through consistent lifestyle habits.
You can improve heart rate variability by building aerobic capacity through moderate exercise, and you can also use high-intensity intervals to provide a stimulus to the nervous system. However, you must also manage factors that decrease heart rate variability. Poor sleep hygiene can decrease heart rate variability, and chronic stress can decrease heart rate variability because stress increase cortisol levels.
Additionally, poor nutrition can decrease heart rate variability through systemic inflammation. You must measure heart rate variability correctly to get accurate data. You should not measure heart rate variability immediately after consuming caffeine or experiencing stress, because caffeine and stress will skew the results.
The most accurate way to measure heart rate variability is to measure it immediately upon waking. You should not focus on a single daily measurement of heart rate variability because one measurement may be an outlier. Instead, you should look at the rolling average of heart rate variability over several week.
By looking at the rolling average, you can see if your heart rate variability is increasing or decreasing over time.
