Five hours is a long time to spend with your blood sugar in a healthier place. That is roughly the daily gain reported for people with type 2 diabetes who use continuous glucose monitors (CGMs), the wearable sensors that track glucose around the clock. The finding is strengthening the case that CGMs should no longer be reserved mainly for people on intensive insulin therapy.
Time in range: the metric that matters
Diabetes care is moving beyond the HbA1c blood test, a three-month average that hides daily swings. Clinicians increasingly track time in range, the share of the day glucose stays between roughly 70 and 180 mg/dL. More time in range means fewer damaging highs, fewer dangerous lows, and steadier energy. A gain of about five hours a day, close to a 20-percentage-point improvement, is the kind of shift associated with meaningfully lower risks of eye, kidney and nerve complications over time. Our Blog regularly translates device studies like this into plain language.
Why seeing the data changes behaviour
A CGM is, at heart, a feedback machine. A small sensor on the arm or abdomen reads glucose from interstitial fluid every few minutes and sends it to a phone. Users see, in near real time, what a bowl of rice, a brisk walk or a poor night’s sleep does to their glucose, and that visibility changes choices in a way quarterly lab results rarely do. Studies of type 2 patients, including many not using insulin, show the devices help people adjust meals, activity and medication timing, with benefits that persist after the novelty fades.
The American Diabetes Association has steadily widened its CGM recommendations, and guidance from the National Institute of Diabetes and Digestive and Kidney Diseases reflects the same direction of travel.
Adoption is the hard part
If the evidence is strong, why is adoption still uneven? Cost and coverage lead the list: sensors are consumables, replaced every 10 to 15 days, and insurers have historically limited reimbursement to insulin users. Prescribing habits lag the evidence, primary-care clinics are stretched, and some patients find wearing a visible medical device stigmatising or simply tiresome. Alarm fatigue, skin irritation and data overload are real complaints, and they argue for good onboarding rather than handing over a box.
Where CGMs go from here
The market is responding. Over-the-counter CGMs aimed at people with type 2 diabetes and even pre-diabetes have begun to appear, prices are edging down, and integration with coaching apps turns raw glucose traces into actionable advice. The policy debate is following the data: every additional study showing hours gained in range makes restrictive coverage harder to defend.
For the hundreds of millions living with type 2 diabetes, the promise is not a cure but control, five better hours at a time, repeated daily. Few interventions in chronic disease offer feedback this immediate or gains this concrete, which is why the small disc on the arm is becoming one of the most consequential wearables in medicine. More health technology coverage is on our homepage.
What to ask before starting
Patients considering a CGM should start with three questions for their clinician. Which device and wear site suit my routine and skin? What target range should I personally aim for, since goals differ for older adults and those with other conditions? And how will we use the data at appointments, because a sensor without a review habit quickly becomes expensive wallpaper. It also helps to expect a learning curve: the first fortnight’s traces can look alarming before patterns emerge, and sharing data with a partner or family member, something most apps support, often improves follow-through. Clinicians, for their part, report that the richest conversations start from the ambulatory glucose profile, the standard summary report every major CGM system can generate, rather than from scrolling raw readings.
