Is average HRV27 normal for sleep health?

You cannot judge whether it is normal or not by relying on this value alone. You have to take a comprehensive look at it based on your daily baseline, age, and recent physical condition to be reliable.

I have been helping friends around me adjust their sleeping habits for almost five years. I have encountered many people who used a single heart rate variability (HRV) value to ask if there was something wrong with their health. I have come across the number 27 many times. The one who impressed me the most was a 28-year-old amateur marathon runner. His resting heart rate was around 40 beats/min all year round. The average HRV during sleep measured for three consecutive months was about 27, and the lowest even dropped to 24 during deep sleep. Not to mention feeling uncomfortable, his overall marathon performance was steadily improving. He went to the cardiology department for a full set of examinations. The doctor said that his heart reserve was much better than that of ordinary people. There is no need to worry about this value.

But last year, I also met a 35-year-old Internet operator. The average sleep HRV for most of the year was around 52. The average sleep HRV for two consecutive weeks was only 26 or 27. He always woke up at 3 o'clock in the middle of the night.

Regarding whether HRV27 during sleep is considered normal, practitioners in different fields have different opinions. Most doctors in the clinical cardiovascular field will refer to the general range. The HRV during adult sleep period is between 20 and 70, which is considered a safe range. 27 is just within this range. If there is no other discomfort, no intervention is needed. ； However, most researchers who do exercise physiology and sleep health pay more attention to individual baseline differences. To put it bluntly, HRV looks at your own body fluctuations, not compared with others. If your average sleep HRV in the past three months has been around 50, and suddenly drops to 27, even if it is still within the universal "normal range," it also indicates that your autonomic nervous system has been too tight recently, and your body is in a state of fatigue or stress.

Some people may not be sure what HRV is. To put it simply, it is the change in the interval between heartbeat and heartbeat. Just like when you are driving a car on a ring road with few cars, the throttle is loose, tight and flexible, indicating that you have enough power to cope with the road conditions, which corresponds to a high HRV.； If you keep pressing on the accelerator and don't dare to let go, and the speed barely changes, it means that you are too tight and don't have enough energy left. This corresponds to low HRV. Your body should be relaxed during sleep. Normally, HRV will be much higher than when you are awake and working.

If your sleep HRV suddenly drops to 27, don’t panic. First think about whether you have drank too much, stayed up late, or taken any medicine that affects your heart rate. These external factors will also lower the value. If after adjusting your lifestyle, the value still does not go up for a week or two, and you still have trouble sleeping and are always tired during the day, just go to the doctor for a checkup. Don’t worry about insomnia when you see an incorrect value, which will drag you down.