Higher glucose variability tied to better well-being in diabetes

Clinical takeaway: For CGM users, chasing a flat curve may not pay off. Swings and time in normal range were both associated with better next-day quality of life. 

Continuous glucose monitors have turned diabetes management into a running score, and many patients read every excursion as a failure. Holding the line steady can mean skipped meals, curtailed exercise, and plans set aside to avoid a swing. Diabetes care names quality of life as a central goal, yet the daily work of glucose control is rarely weighed against it. 

Decades of evidence connect tighter glycemic control to fewer complications, and CGM metrics now let patients and clinicians pursue that control hour by hour. What the metrics miss is how the pursuit lands on a patient's day: whether the effort behind a smooth tracing costs energy, spontaneity, or sleep. To understand more, researchers paired glucose monitoring data with patients' own daily reports of how life was going in adults with type 1 and type 2 diabetes. 

Days with more glucose variability were followed by days on which participants rated their quality of life higher, the inverse of what a flat-curve ideal would predict. More prior-day time in normoglycemia, defined in this study as 70 to 140 mg/dl rather than the conventional 70 to 180, was also associated with better next-day ratings. Time above range and time below range showed no association with next-day quality of life in either direction. 

The lag mattered since same-day glucose parameters showed no relationship with same-day quality of life. Better sleep the preceding night and higher prior-day energy levels also tracked with higher ratings the following day. 

The findings come from the PRO-MENTAL study, not yet submitted for publication. Researchers followed 400 adults with type 1 or type 2 diabetes (72% with type 1, mean age 47, and mean A1C 7.6%) pairing 14 days of CGM data with daily quality-of-life ratings on the WHO-5 scale. Models adjusted for age, sex, diabetes type, and the prior day's quality-of-life score. 

The pattern the authors describe is not an argument against glycemic targets; time in normoglycemia carried its own association with better days. The tension resides in how patients get there. A tracing achieved through restriction and vigilance may read well to a clinician while costing the patient the parts of a day that make it worth rating highly. 

"Interestingly, higher-than-usual glucose variability was also associated with improved next-day quality of life," the authors noted. "These findings may suggest that individuals experience lower quality of life when attempting to minimize glucose fluctuations too strictly, potentially due to the associated burden or restrictions in daily life, which may contribute to some people living with diabetes feeling unable to safely engage in certain activities." 

Source: Ehrmann D, et al. (2026 Sep 11) Annual Meeting of the European Association for the Study of Diabetes (EASD) 2026. "Fun is not a straight line": greater glucose variability and more time in normoglycaemia on the previous day are significantly associated with next-day quality of life