Normal RMSSD generally decreases as adults get older. Younger adults often have higher RMSSD values, while people in their 50s, 60s, and beyond tend to have lower readings. However, no single RMSSD value is considered normal for everyone. Age, fitness, sleep, stress, health conditions, and measurement methods all influence results.
The present-day HRV is a valuable marker of the body’s responses to daily activities, stress, and recovery. One common measure is RMSSD, which looks at change in the amount of time between heart beats on a small scale.
If you're new to tracking HRV, you might be wondering if your RMSSD is normal for your age.
The answer is not always easy to find. Two healthy adults of the same age can have very different RMSSD values. Knowing this difference, you can interpret your measurements without too much worry about individual measurements.
RMSSD = root mean square of successive difference. It measures the short-term variations between two normal heartbeats in a row.
RMSSD is derived from RR intervals, the time intervals between successive heartbeats.
It is widely used in assessing the function of the parasympathetic nervous system, particularly the body's ability to control heart rate at rest and during recovery.
Higher resting RMSSD values are usually indicative of higher parasympathetic activity. Stress, fatigue, illness, or lack of recovery can cause the readings to be reduced.
Reduction of RMSSD is observed in relation to age. Individual measurements vary widely, but large-scale population studies have found patterns of age.
The table below presents median RMSSD values from the Lifelines Cohort Study, which studied 10 second resting electrocardiograms.
| Age Group | Men (Median RMSSD) | Women (Median RMSSD) |
|---|---|---|
| 20–24 years | 47.6 ms | 52.1 ms |
| 25–29 years | 42.3 ms | 47.5 ms |
| 30–34 years | 36.9 ms | 42.3 ms |
| 35–39 years | 32.8 ms | 37.9 ms |
| 40–44 years | 29.0 ms | 33.9 ms |
| 45–49 years | 26.0 ms | 29.2 ms |
| 50–54 years | 23.7 ms | 26.6 ms |
| 55–59 years | 21.0 ms | 22.5 ms |
| 60–64 years | 19.1 ms | 20.5 ms |
| 65–69 years | 17.7 ms | 17.8 ms |
| 70–74 years | 16.0 ms | 18.3 ms |
| 75+ years | 14.9 ms | 16.1 ms |
Values from longer recordings, smartwatches, and other HRV monitoring devices can vary.
Parasympathetic regulation of heart rate typically changes with age, so younger adults generally have higher RMSSD values.
Regular physical activity, good sleep, and proper recovery can help support healthy HRV patterns.
But sometimes an active person will have a lower reading after a hard workout or a bad night’s sleep.
RMSSD values tend to be lower in middle age.
Stress at work, quality of sleep, physical condition, and pre-existing medical conditions can also affect the results.
Rather than comparing each reading to the population averages, see if your RMSSD is reasonably stable over time.
Older adults tend to have lower average RMSSD values as well.
That doesn't necessarily mean that their nervous system is broken.
Perhaps an abnormally high reading on one occasion is not as informative as a more stable reading of RMSSD.
Age is a factor, and many daily factors influence RMSSD.
These factors often overlap, so one reading can’t tell you exactly what’s going on inside your body.
The RMSSD stress response relationship is useful for understanding how the autonomic control of the HR varies in different conditions.
Psychological or physical stress can also drive lower RMSSD readings as parasympathetic activity can decrease during these stressors.
Increased RMSSD may occur during relaxation and recovery.
For example, you might have a lower RMSSD after a bad day at work and a higher one after a good night’s sleep.
But those patterns aren’t etched in stone. Breathing, movement, medications, and errors in measurement can also lead to variations.
RMSSD formula: Square root of the mean of the sum of the squares of the differences between consecutive normal RR intervals.
RR is the number of the intervals included, and N is the number of normal heartbeat intervals in a row.
You work out the successive differences. You square them. You find the average. You take the square root.
The result is in msecs.
Reliable measurements of the RR interval and proper treatment of irregular or incorrectly detected beats are needed to perform the calculation correctly.
You can see how the body’s responses change under controlled conditions by performing a physiological stress test.
Combined with heart rate, RMSSD may offer further information about autonomic responses at rest, during activity, and in recovery.
For instance, changes in immediate HRV can be shown by comparing HRV measurements taken before and after a relaxation exercise.
HRV monitoring is not a substitute for a clinical cardiac stress test and cannot be used to independently diagnose stress-related or cardiovascular conditions.
Tools such as HRV Live enable users to view RR intervals and observe real-time changes in HRV.
Aging brings natural changes, but healthy routines may help better regulate the autonomic nervous system.
Try these helpful habits:
Aim for the higher number together. Longer term, meaningful and consistent patterns are more valuable.
Pick a time of day that you can do every day and make sure that you are relaxed and not distracted.
Try to use the same device, length of recording, and position of body.
Don’t look at one result; look at changes over a few days/weeks.
If your RMSSD changes unexpectedly, consider recent sleep, exercise, illness, or stress before jumping to conclusions.
If you have any changes that you cannot explain, especially if you also have symptoms, you should speak to your healthcare professional.
An RMSSD of 30 ms may be normal for some adults, depending upon age and measurement method. It is not capable of determining health status.
Yeah. People respond differently. Population studies usually show a reduction of median RMSSD values with age in adulthood.
Not necessarily. Higher RMSSD generally indicates more parasympathetic influence. Measurement errors or irregular heart rhythms can also cause very high values.
Yes, psychological and physical stress can lower RMSSD, but there are many reasons why the individual response is variable.
Regular measurements can be useful for seeing trends, as long as they are done consistently. Measurements from time to time also provide valuable information.
Normal RMSSD for age provides useful context for interpreting heart rate variability measures.
The tendency of RMSSD to decrease with age is not necessarily an indicator of healthy autonomic function, as there is not one number to do so.
The same measurements, individual trends, and the big picture of what is impacting recovery and stress.
Check out HRV Live to see your current heart rate variability measurements and learn more about how your RMSSD changes with conditions.
Disclaimer
hrv.live, rmssd.com, and Time Domain Labs tools are for informational and educational purposes only. Not a medical device. Not FDA cleared or approved. No medical advice is provided.
We do not diagnose, treat, cure, or prevent any disease or medical condition. RMSSD, pNN50, and RR interval data are measures of autonomic activity, not a medical diagnosis.
Do not use this information to make medical decisions. Always consult a qualified healthcare professional for medical concerns. If you have a medical emergency, call 911.
You assume full responsibility for use of this site and its data.