Researchers found that sleep duration and the timing of physical activity were linked to blood glucose fluctuations, suggesting that when people rest and move may matter more than previously recognized. Credit: Shutterstock

Timing may matter in insulin-treated type 2 diabetes; patients with the steadiest daily rhythms were 2.3 times as likely to meet blood sugar goals, while afternoon activity was linked to smaller swings.

People with type 2 diabetes who use insulin need to keep blood glucose from climbing too high or falling too low. In a study of 122 patients, 46.3% of those with the most stable daily rhythms achieved their blood glucose management goal, compared with 20.0% of those with the least stable rhythms, a roughly 2.3-fold difference.

These daily cycles, known as circadian rhythms or biorhythms, help regulate sleep and activity over approximately 24 hours. Greater rhythm stability remained associated with a higher likelihood of meeting glucose management goals even after the researchers accounted for factors including age, body mass index (BMI), and HbA1c, a measure of average blood glucose over recent months.

Wearables link daily rhythms with glucose patterns

The study involved patients receiving insulin treatment at Ansan Hospital from 2021 to 2024. Participants wore continuous glucose monitors and wearable activity monitors for 10 days, providing records of glucose changes, sleep times, physical activity levels, and heart rates. Pairing the devices allowed the researchers to examine how daily rhythms related to glucose patterns.

A research team led by (From Left) Dr. Lee Da young, Dr. Nan Hee Kim, Dr. Lee Heon-jeong, and Dr. Lee Jung-been. Credit: KU Medicine

The research was led by Dr. Da Young Lee and Dr. Nan Hee Kim of the Division of Endocrinology and Metabolism in the Department of Internal Medicine at Ansan Hospital, Dr. Heon-jeong Lee of the Department of Psychiatry at Anam Hospital, and Dr. Jung-been Lee of the Division of Computer Science and Engineering at Sun Moon University.

“The conventional management methods of diabetes focused on diet, exercise, and medication. But this research showed that we also need to pay attention to the management of biorhythms. Maintaining regular and stable lifestyle rhythms can help manage your blood glucose levels,” said Dr. Da Young Lee.

Sleep and afternoon activity linked to steadier glucose

Sleep duration was associated with both low-glucose episodes and the extent of glucose fluctuations. Patients who got sufficient sleep had a lower risk of hypoglycemia, or low blood glucose, and smaller swings in their glucose levels.

The relationship between physical activity and glucose control varied depending on when patients were active. To examine that timing, the researchers compared step counts with glucose indicators across four periods: early morning, from midnight to 6 a.m., morning, from 6 a.m. to noon, afternoon, from noon to 6 p.m., and night, from 6 p.m. to midnight.

Afternoon activity showed the clearest association with glucose control. Patients who were more active during those hours tended to spend more time within their target glucose range and had less variability in their glucose readings.

Testing whether rhythm changes improve glucose control

The findings establish associations, but they do not show that changing daily rhythms will itself improve glucose control. Testing that possibility will require an intervention.

“Now that we have confirmed the correlation between biorhythms and blood glucose management, we will proceed to conduct a follow-up study to verify whether active intervention in patients’ lifestyles for adjusting their biorhythms would improve their actual blood glucose levels,” Lee added. “Furthermore, we plan to validate the relationship between biorhythms and various diabetes complications such as diabetic kidney disease and retinopathy.”

Reference: “Association of daytime circadian-aligned activity with glycemic control in type 2 diabetes: Insights from continuous glucose monitoring and wearable data” by Da Young Lee, Jung-Been Lee, Inha Jung, Ji A Seo, Heon-Jeong Lee and Nan Hee Kim, 19 February 2026, Metabolism.
DOI: 10.1016/j.metabol.2026.156570

Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.