Continuous glucose monitor (CGM)
A small sensor on your arm that tracks glucose every few minutes - showing how your body responds to meals, sleep, stress and exercise.
TypeWearable
HowA small sensor applied to the back of your arm; readings go to your phone.
How often2–4 weeks is usually enough to learn your patterns.
BeforeKeep eating normally so the data reflects real life.
WhoCurious, health-focused people and those with prediabetes who want feedback.
What a CGM shows that a blood test can’t
HbA1c gives you a 3-month average. A CGM shows the whole movie - how your glucose rises and falls through each day.
After meals
“Which foods spike me?”
See how your body responds to the same meal eaten at different times, or with a walk afterward.
Personal feedback
Overnight
“Is my sleep affecting it?”
Poor sleep and late meals often show up as higher morning glucose.
Hidden patterns
Honest limits
“Is every spike bad?”
Short rises after eating are normal. For people without diabetes, the long-term benefit isn’t proven yet.
Tool, not a diagnosis
Getting real value from a CGM
01
Keep a simple log
Note meals, sleep and exercise.
02
Test one change at a time
E.g. a walk after dinner.
03
Look at averages
Daily patterns matter more than single peaks.
04
Share with your provider
Especially if values run high.
Is it right for you?
Worth considering if…
- You have prediabetes and want real-time feedback.
- You want to learn how your meals and habits affect you.
- You’re an athlete fine-tuning fuelling.
A better option if…
- You want to screen for diabetes - HbA1c and fasting glucose are the standard tests.
- You’re likely to worry about every spike - the data can cause anxiety without clear benefit.
How it’s measured
Prescription CGM
Used in diabetes; can be ordered by your provider.
Over-the-counter CGM
Some sensors are now sold without a prescription for general wellness.
The full picture
What is it?
A wearable sensor that measures glucose in the fluid under your skin every few minutes.
What type of test is it?
A wearable monitoring tool.
What does it measure?
Interstitial glucose levels, around the clock.
Why might someone consider it?
To see personal glucose responses to food, sleep, stress and exercise.
Who is it most relevant for?
People with prediabetes or diabetes, and curious health-focused users.
How is it performed?
A sensor is applied with a small applicator and worn for about 10–15 days.
How often might it be considered?
A 2–4 week block, repeated occasionally if useful.
What can the result help you understand?
How your daily habits affect your glucose.
What are its limitations?
Readings lag blood glucose, sensors can be off, and benefit in people without diabetes isn’t well established.
What should it be viewed with?
HbA1c, fasting insulin, sleep, activity and meal timing.
Where to get it
Through your provider
Especially if you have prediabetes or diabetes.
Pharmacies & online
Some sensors are available over the counter.
Wellness programmes
Some bundle a CGM with coaching.
Names are examples only, not endorsements. Your provider can often order the same test - and help interpret it.
Connected to
Questions to ask your provider
- Would a CGM help me, or is HbA1c enough?
- What glucose range should I aim for?
- How should I read post-meal spikes?
Ziva Health
One test is a snapshot. Ziva shows the whole story.
Ziva brings your lab results, wearables and daily readings together - and Isabella tells you what’s changing and what to ask your provider next.
Refer Ziva to my provider / care team
Is your provider not on Ziva yet? Send them a link in under a minute - once they join, they’ll see your Continuous glucose monitor result alongside your other trends and get alerts directly.
Refer my providerAlready seeing your provider?
Bring your Ziva 30-day report to your next appointment - your Continuous glucose monitor result and daily trends in one view, so the conversation starts with the full picture.
Get my 30-day reportNo provider? Find a clinical partner
Being listed doesn’t mean everyone needs this test. Educational only — not medical advice. Results should be interpreted with a qualified clinician. ← Back to Know What to Test