What Is a Good HRV? Normal Ranges by Age, Why Yours Is Only Comparable to Yours, and How to Raise It

A good HRV is a number you cannot look up. It is the one that sits above your own last thirty days.

Most operators meet heart rate variability the same way: a ring or a strap arrives, the app shows a number in the thirties or the sixties, and the first question is whether that is good. The second question is why a friend's number is double. Both questions have the same answer, and it is not the one the leaderboard implies.

HRV is one of the few metrics that reads the system you run a business with. It is also one of the most misread, because the published ranges depend on which metric, which recording length, which age group and which device produced them. Compare across any of those and you are comparing noise.

This article gives you the two numbers you will actually see, the normal ranges with their populations named, what age does to them, why your own baseline is the only comparison that holds, what moves the number in each direction according to the research, and a six-week plan with a training decision rule. Education, not diagnosis: if you have a heart condition, an arrhythmia, or take medication that affects heart rate, talk to your doctor before you act on any of this.

What HRV measures, and the two numbers you will see

Heart rate variability is the variation in time between consecutive heartbeats. A heart that beats 60 times a minute does not beat once a second; the gaps stretch and shrink by milliseconds, and those changes are what HRV measures.

The Oura help page describes it as "a measure of the millisecond-level variation in time between your heartbeats" that "offers insight into the balance between the two divisions of your autonomic nervous system": the sympathetic branch, the fight-or-flight response, and the parasympathetic branch, the rest-and-digest mechanism.

Two metrics do most of the work in consumer devices and clinical papers. A 2017 review in Frontiers in Public Health, "An Overview of Heart Rate Variability Metrics and Norms," defines both.

RMSSD. "The root mean square of successive differences between normal heartbeats (RMSSD) is obtained by first calculating each successive time difference between heartbeats in ms. Then, each of the values is squared and the result is averaged before the square root of the total is obtained." The review adds that "The RMSSD reflects the beat-to-beat variance in HR and is the primary time-domain measure used to estimate the vagally mediated changes reflected in HRV." Most wearables report RMSSD or a derivative of it. This is the number that tracks recovery.

SDNN. The standard deviation of all normal beat-to-beat intervals over the recording. The same review calls SDNN the "gold standard" for medical stratification of cardiac risk "when recorded over a 24 h period," and notes it "is more accurate when calculated over 24 h than during the shorter periods" used in brief sessions.

One sentence from that review should sit above every HRV chart you ever read: the authors "caution that 24 h, short-term, and ultra-short-term normative values are not interchangeable." A five-minute morning reading, an overnight average and a 24-hour clinical recording are three different measurements with three different normal ranges.

The published normal ranges, with the metric and the population named

Here are the figures the research actually publishes. Read the column headers before the numbers.

Metric	Recording	Population	Published figure
RMSSD	Short-term (about 5 min)	21,438 healthy adults, 44 studies	Mean 42 ms (SD 15), study range 19 to 75 ms
SDNN	Short-term (about 5 min)	Same review	Mean 50 ms (SD 16), study range 32 to 93 ms
SDNN	24 hours	Clinical risk categories	Below 50 ms unhealthy, 50 to 100 ms compromised, above 100 ms healthy
Device HRV	Overnight average	Oura users	"typical values ranging from under 20 to over 200 milliseconds"

The short-term rows come from a 2010 systematic review in Pacing and Clinical Electrophysiology, "A quantitative systematic review of normal values for short-term heart rate variability in healthy adults," which pooled "Forty-four studies" involving "21,438 participants." The 2017 review reproduces its table: short-term SDNN mean 50 ms with a standard deviation of 16 and a range across studies of 32 to 93; RMSSD mean 42 ms, standard deviation 15, range 19 to 75.

Two cautions from the 2010 authors. "Values for short-term HRV measures from the literature were lower than Task Force norms," meaning the older reference values most charts still copy run high. And "A number of studies demonstrate large interindividual variations (up to 260,000%), particularly for spectral measures." The 2017 review adds that the pooled sample "included three large populations with a minimum age of 40," which "may explain their comparatively lower HRV values."

The 24-hour row is a different animal. The 2017 review states that "Based on 24 h monitoring, patients with SDNN values below 50 ms are classified as unhealthy, 50–100 ms have compromised health, and above 100 ms are healthy." That is a clinical, all-day SDNN in patient populations. It is not your ring's overnight RMSSD, and a 45 on your wrist does not place you in the "unhealthy" row.

The last row is the honest one. The Oura page states that "HRV is a personalized metric, with typical values ranging from under 20 to over 200 milliseconds" and that it "is influenced by various factors like age, health status, and fitness level." A tenfold spread among healthy users is not a range you can position yourself inside with any precision.

Age changes the number, which is why your friend's HRV is noise

The largest reason two healthy people show different numbers is age. A 1998 study in the Journal of the American College of Cardiology, "Twenty-four hour time domain heart rate variability and heart rate: relations to age and gender over nine decades," recorded 24-hour HRV in "260 healthy subjects (10 to 99 years old; 112 male, 148 female)."

The finding: "HRV decreased with aging, the pattern of change being measure dependent." For the metric your device shows, the decline is steep and early. "Using pNN50 and rMSSD, HRV decreased most rapidly, reaching 24% and 47% of baseline, respectively, by the sixth decade and then stabilized." Baseline here means second-decade values. A healthy operator in their fifties is expected to carry roughly half the RMSSD of a healthy twenty-year-old, and that is normal physiology, not a warning.

Sex matters too, until it does not. "At age <30 years, HRV for all measures was lower in female than male subjects. Gender differences decreased at age >30 years and disappeared at age >50 years."

Now stack the variables. Age, sex, the metric, the recording window, the device's algorithm, whether the reading is overnight or a five-minute morning sample. Two people comparing numbers differ on most of them. The vendor says it plainly: "It's important to compare your current HRV only against your own historical trends, not against others." The leaderboard is a category error.

Why your own 30-day baseline is the whole game

The research on athletes reached the same conclusion from the other direction. A 2013 review in Sports Medicine, "Training adaptation and heart rate variability in elite endurance athletes," found that in elites "studies have revealed both increases and decreases in HRV to be associated with negative adaptation," and that "signs of positive adaptation, such as increases in cardiorespiratory fitness, have been observed with atypical concomitant decreases in HRV."

Higher is not simply better, even for people whose job is to be fit. What the authors recommend instead is "the use of appropriate averaging techniques" and longitudinal monitoring, because "longitudinal HRV monitoring in elites is required to understand their unique individual HRV fingerprint."

Your fingerprint is the asset. A single reading is weather. A rolling average over a week, compared against a month of the same, is climate, and climate is what you make decisions on.

Why this matters to an operator rather than a marathoner: a 2012 meta-analysis in Neuroscience and Biobehavioral Reviews, "A meta-analysis of heart rate variability and neuroimaging studies," proposes that "Heart rate variability may provide an index of how strongly 'top-down' appraisals, mediated by cortical-subcortical pathways, shape brainstem activity and autonomic responses in the body," and that it "provides an important window into understanding stress and health." The authors also propose that "the default response to uncertainty is the threat response." Uncertainty is the operator's working medium. HRV is a readout of how much capacity you have to meet it with judgment rather than reflex. The HRV for founders article takes that thread into the calendar.

How to build the baseline

1. One device, one window. Overnight is the cleanest. Oura, for example, "takes five-minute samples, not just a single reading, throughout the night," and reports "the mean of all five-minute samples taken while you sleep." It measures only during sleep because daytime readings are disturbed by "drinking water, getting up to use the bathroom, or watching an exciting TV show." Whatever device you use, keep the method constant. The wearable comparison covers the differences.
2. Thirty nights, no interventions. Record the daily value and nothing else. You are learning your range, not improving it yet.
3. Compute a seven-day rolling mean and note your personal band: the highest and lowest seven-day means in the month.
4. Log the obvious inputs alongside: alcohol, bedtime, illness, hard sessions. The pattern will be visible by week three.

What lowers it, according to the research

Each lever below is stated only as far as a fetched source carries it.

Alcohol. The clearest acute evidence comes from a 2017 study in the European Heart Journal that recorded ECGs in "3028 voluntary participants" at a beer festival, the MunichBREW study. "Respiratory sinus arrhythmia measuring autonomic tone was significantly reduced under the influence of alcohol." Respiratory sinus arrhythmia is the vagal rhythm that RMSSD largely reflects. The authors describe the result as "autonomic imbalance." For the business cost of the same drinks, see the honest numbers on alcohol.

Illness, stress and overtraining. The vendor's own summary: "Low HRV is associated with activation of your 'fight-or-flight' system. It's commonly linked to stress (both good and bad), illness, and overtraining." Treat that as a manufacturer's description of what its users see, not a trial result.

Hard training. The 2013 athlete review is the caution here: a drop after a heavy block is not automatically damage, since fitness gains have been observed "with atypical concomitant decreases in HRV." Read the drop with the rest of the picture, including resting heart rate, which the resting heart rate guide covers.

Sleep. The vendor page states that "Higher average nighttime HRV is also associated with better sleep quality." That is an association in user data. This article did not fetch a controlled sleep-restriction trial measuring HRV, so no size of effect is claimed.

Late or heavy meals. Not established by any source fetched for this article. The eating for HRV protocol covers the practical side; test it against your own baseline rather than taking it on faith.

What raises it over weeks

Aerobic training. A 2005 meta-analysis in Medicine and Science in Sports and Exercise, "Effects of exercise on heart rate variability," pooled "13 studies measuring HF (N=322 cases)" and found "an overall effect size of d=0.48 (C.I. 0.26-0.70, P=0.00003)." Its conclusion: "Exercise training results in significant increases in RR interval and HF power. These changes are influenced by study population age." HF power is the frequency-domain cousin of RMSSD, and both track vagal activity. The training that produced it was chronic, not a single session. This is the case for the base work in zone 2 training.

Slow breathing. A 2018 systematic review in Frontiers in Human Neuroscience, "How Breath-Control Can Change Your Life," examined techniques at "<10 breaths/minute" across the 15 studies that met its criteria and found that "Slow breathing techniques promote autonomic changes increasing Heart Rate Variability and Respiratory Sinus Arrhythmia." That is an acute effect during and around the practice. Five minutes a day is a cheap experiment to run against your baseline; the box breathing protocol gives a pattern to use.

Removing the things that lower it. This is inference, not a trial: if alcohol acutely reduces vagal tone, nights without it should read higher. Your thirty-day log will tell you whether that holds for you.

The 6-week operator plan

The plan is Apex protocol, built from the evidence above and from the athlete review's advice to average rather than react. Nothing in it needs to be bought.

Weeks 1 and 2: baseline

1. Same device, overnight, every night. No new habits yet.
2. Record the daily value and the seven-day rolling mean. Note your band.
3. Log alcohol, bedtime, hard sessions and any illness beside the numbers.

Weeks 3 and 4: install the levers

1. Three zone 2 sessions a week, 40 to 60 minutes, conversational pace.
2. No alcohol on weeknights. Keep the weekend as a controlled comparison if you want to see the effect in your own data.
3. Five minutes of slow breathing, about six breaths a minute, before bed.
4. Fixed lights-out and wake time.

Weeks 5 and 6: hold, and add one hard session

1. Keep every lever from weeks 3 and 4.
2. Add one high-intensity session a week, placed after a good night.
3. Apply the decision rule below every morning.
4. At the end of week 6, compare the seven-day mean with the week 2 mean. That difference, in your own units, is your answer to "is my HRV good."

The training decision rule

• Today's reading inside your personal band: train as planned.
• Below the band for one day: keep the session, cut the intensity. One day is weather.
• Below the band for three consecutive days, with resting heart rate up: easy day or rest, and check sleep, alcohol and whether you are getting ill.
• Above the band after a hard block: do not chase it with more load. The athlete review found that direction is not a simple signal either.

Frequently asked questions

What is a good HRV?

There is no universal good number. Published short-term norms in 21,438 healthy adults put RMSSD at a mean of 42 ms with a range across studies of 19 to 75, but age, sex, recording length and device all shift the figure, and one vendor reports typical user values from under 20 to over 200 ms. A good HRV is one that is stable or rising against your own 30-day baseline.

What is a normal HRV by age?

HRV falls with age. In a 24-hour study of 260 healthy people aged 10 to 99, RMSSD dropped to about 47% of second-decade values by the sixth decade and then stabilised. Published tables of exact values by age exist, but they are tied to a specific metric and recording length, so a chart that does not name both is not usable for your device.

Is an HRV of 30 bad?

Not on its own. A 30 ms RMSSD sits inside the range of published short-term studies in healthy adults, and for someone over 50 it can be entirely normal physiology. The clinical cut-off of 50 ms that circulates online refers to 24-hour SDNN in patient populations, a different metric and recording. Judge 30 against your own trend, and raise medical questions with a doctor.

Why is my HRV lower than my friend's?

Most likely age, then sex, then the device and the time of measurement. The 1998 nine-decade study found RMSSD declining steeply into the fifties and women under 30 reading lower than men. Two people on different devices measuring at different times are not comparing the same thing. Vendors themselves advise comparing only against your own history.

How can I raise my HRV?

Over weeks, aerobic training has the best evidence: a meta-analysis of 13 studies found exercise training significantly increased vagal HRV measures. Acutely, slow breathing under ten breaths a minute increases HRV during the practice. Alcohol measurably reduces vagal tone, so removing it on weeknights is a sensible test. Track the result against your own baseline rather than against a target number.

Measure yourself against yesterday

The question "what is a good HRV" has an operator's answer: good is a trend you own, not a number you borrow. The research gives you the ranges, tells you they are not interchangeable, and then points you back to your own fingerprint, averaged over a week and compared over a month.

That is the same discipline the Stoics asked for in the evening review: judge today against your own standard, not against the person at the next desk. The body runs the same rule. Build the baseline, move the levers one at a time, and let the log, not the leaderboard, tell you what is good.

The free 5-Day Stoic Operator Challenge installs the daily structure the plan above depends on: training as a fixed appointment, a short evening review that logs the inputs, and a morning that starts with a reading instead of a reaction.