What Is a Normal Glucose Variability (CV) for Someone Without Diabetes?

There is no agreed non-diabetic normal glucose variability CV; one healthy CGM cohort had a mean CV of about 17% (Shah et al. 2019), and ≤36% is a diabetes stability target, not a diagnostic cut-off.

The 36% number is a diabetes target, not a non-diabetic normal. The non-diabetic value shown is the mean CV reported by Shah et al. 2019, not an official cut-off.

What is a normal glucose variability CV for someone without diabetes?

No professional body has defined a normal CV for people without diabetes. The ≤36% figure comes from the International Consensus on Time in Range, an agreement for interpreting CGM data in people with diabetes. It says many people with diabetes should aim for a coefficient of variation of 36% or less as a marker of stable glucose. That does not make 37% abnormal in a non-diabetic person, and it does not make 20% a universal healthy number.

One multicenter CGM study in healthy non-diabetic adults reported about 96% of time between 70 and 140 mg/dL (3.9 to 7.8 mmol/L), with a mean CV around 17% (Shah et al. 2019). That is context, not a pass mark. Sensor accuracy, age, meal timing, stress and whether you include the first day of a sensor all move the number. The non-diabetic CV estimate is less firmly established than the diabetes target because studies are smaller, use different sensors, and handle sensor noise differently.

Where the 36% target actually comes from

The 36% target was written for people with diabetes, not for healthy people trying to stay healthy. In diabetes, a high CV plus a high average can mean more time in extreme glucose ranges. So the consensus asked for both enough time in range and stable readings. It was a stability goal, not a normal range found by measuring people without diabetes.

Using 36% as a wellness cut-off is a category error. Artifacts and short-term factors can raise CV without a change in underlying health, but a CV above 36% is not a diagnosis in either direction. A person with diabetes can have a CV below 36% and still need medical care. The target belongs to a specific context.

How CV is calculated and why it beats standard deviation

CV is standard deviation divided by mean glucose, multiplied by 100. If your mean glucose is 100 mg/dL and your standard deviation is 15 mg/dL, your CV is 15%. If your mean is 150 mg/dL with the same standard deviation, your CV is 10%. Same absolute scatter, smaller relative scatter.

Because standard deviation and mean use the same units, CV is a percentage. It does not matter whether your sensor exports mg/dL or mmol/L. But CV has limits. A low mean can make a small absolute spread look like a high CV, and a high mean can hide big absolute swings inside a normal-looking CV. That is why the graph matters, not just the number.

What a high or low CV looks like on a CGM graph

On an ambulatory glucose profile, low CV looks like a narrow band. Days follow a similar shape, with small post-meal bumps and a fairly flat overnight line. High CV looks like wide bands, tall after-meal peaks and deeper dips. Two people can have the same mean glucose and very different CV.

Some high CV is sensor, not you. Sharp overnight dips that recover within minutes are often compression lows from lying on the sensor. The first day of a new sensor is noisy. If a high CV is driven by a few short artefacts and your day profile is otherwise steady, interpret around those points instead of treating them as glucose variability. The free report marks possible overnight compression lows.

What should I aim for if I don't have diabetes?

There is no official target. If you are using a wellness sensor, a sensible read is this. Shah et al. 2019 reported a mean CV around 17% in a non-diabetic multicenter cohort, so values near that observed mean are common in that study, not a health certification. Values above that observed mean can reflect sensor artifacts or short-term factors; a CV above 36% is still not a diagnosis.

Do not chase a flat line. Meals are supposed to raise glucose. Healthy adults spend about 3 hours per day above 140 mg/dL, and post-meal rises are common (Spartano et al. 2024). That is normal variability, not failure.

If you also have a lab HbA1c in the diabetes range, symptoms such as excessive thirst or unexplained weight loss, or glucose readings that worry you, that is a conversation with a doctor. CV alone cannot diagnose anything.

How to get your own CV from a LibreView, Dexcom, Stelo, Lingo or SiBionics export

You do not need to calculate CV by hand. The free report reads the export and shows variability/CV, AGP, time in range, GMI, and biggest rises.

• Export your data. LibreView has a Download glucose data option. Dexcom Clarity, Stelo, Lingo and SiBionics let you export a CSV from their portal or app.
• Open the free report and drop the file. No account, nothing uploaded.
• Look at CV next to the 24 hour profile and the biggest rises. A single number without the graph can mislead.

Already wearing a sensor? Drop your LibreView, Dexcom, Stelo, Lingo or SiBionics export into the free CGM report at https://healthosx.com/glucose and see your own CV, AGP, time in range, GMI and biggest rises. No account and nothing uploaded. The free report is a wellness tool, not a medical device.