For the millions of adults living with type 2 diabetes who manage their condition without insulin, a small sensor worn on the arm could make a measurable difference to everyday health. The largest clinical trial of its kind, published in the New England Journal of Medicine, has found that continuous glucose monitors (CGMs) help these patients spend approximately five more hours a day in their target blood sugar range compared with traditional finger-prick testing.
What the Trial Found
Continuous glucose monitors are small wearable devices that track glucose levels around the clock, sending readings to a smartphone or receiver every few minutes. Until now, the strongest evidence for their benefit has come from people who use insulin, for whom the devices are widely prescribed. This new trial focused on a much larger and often overlooked group: adults with type 2 diabetes who do not use insulin at all.
The results were striking. Participants using a CGM spent roughly five additional hours each day with their blood sugar inside the recommended target range. In diabetes care, “time in range” is increasingly treated as one of the most meaningful measures of control, because it captures the daily reality of glucose highs and lows far better than a single quarterly lab test.
Researchers at the University of Colorado Anschutz Medical Campus, who reported the findings, describe the study as the largest trial of its kind. You can read the university’s summary of the research in its report on the glucose monitor trial.
Why Time in Range Matters
Blood sugar that runs too high for too long quietly damages blood vessels, nerves, kidneys and eyes. Blood sugar that swings low can cause dizziness, confusion and, in severe cases, dangerous episodes. Spending more hours of the day in the target zone means less of that cumulative damage — and, just as importantly, it gives patients feedback they can act on in the moment.
That feedback loop is the real power of a CGM. A finger-prick test tells you where your glucose is at one instant. A monitor shows you the trend: what a particular meal did to your levels, how a walk after dinner flattened the spike, or how a poor night’s sleep showed up the next morning. Many patients describe it as the first time their condition became visible — and therefore manageable.
Simple habits amplify the effect. As we covered in our guide to the 10-minute walk after meals, even gentle movement after eating measurably blunts glucose spikes — exactly the kind of cause and effect a CGM makes obvious within days of wearing one.
A Shift in Who Gets the Technology
Historically, CGMs were reserved for people with type 1 diabetes and those with type 2 diabetes on intensive insulin therapy. Cost and insurance coverage were the main barriers: without a prescription category that includes them, patients paid out of pocket for sensors that need replacing every 10 to 14 days.
Evidence like this trial puts pressure on that model. If people who are earlier in the course of the disease — and far more numerous — gain five healthier hours a day from the technology, the long-term savings from avoided complications could be substantial. Diabetes specialists have been moving in this direction for several years, and guidelines have steadily widened. A trial of this scale, in the world’s most influential medical journal, gives clinicians and insurers a firmer basis for expanding access.
What It Means If You Live With Type 2 Diabetes
If you manage type 2 diabetes without insulin, this study is a good reason to raise CGMs at your next appointment — even if only for a trial period of a few weeks. A short stint with a sensor can reveal patterns that months of occasional finger-pricks never will: the breakfast that quietly spikes you, the evening snack that lingers, the exercise that reliably brings you down.
It is also worth remembering what the technology cannot do. A monitor does not lower glucose by itself; it informs the choices that do. Medication, food, movement, sleep and stress still drive the numbers. But as this landmark trial shows, seeing those numbers clearly — hour by hour, day by day — helps people spend far more of their lives in the zone where long-term health is protected. Five extra hours a day adds up to more than 1,800 hours a year, and that is a difference worth taking seriously.