Exercise remains an important component of diabetes management, although concerns regarding nocturnal hypoglycemia may limit physical activity participation in adults with type 1 diabetes. An analysis from the Type 1 Diabetes and Exercise Initiative (T1DEXI) study published in Diabetes Care evaluated modifiable factors associated with postexercise nocturnal hypoglycemia.

This prospective real-world cohort study analyzed overnight continuous glucose monitoring data from 496 adults with type 1 diabetes across 12,340 nights following exercise days and sedentary days. Nocturnal hypoglycemia was defined as continuous glucose monitoring glucose levels between 54 and 69 mg/dL (level 1) or below 54 mg/dL (level 2) lasting at least 15 minutes between midnight and 6:00 a.m.

Findings

• Exercise days demonstrated higher rates of level 1 nocturnal hypoglycemia than sedentary days (15.6% vs 13.1%; P = 0.001).
• Lower preexercise time below range, higher preexercise and bedtime glucose levels, and absence of hypoglycemia during or within 4 hours after exercise were associated with lower overnight hypoglycemia risk.
• Participants with time below range of at least 4% during the 24 hours before exercise demonstrated higher risks of level 1 and level 2 nocturnal hypoglycemia than those with less than 4% time below range (both P < 0.001).
• Hybrid closed-loop users demonstrated substantially lower nocturnal hypoglycemia rates than participants using standard insulin pumps or multiple daily injections for both level 1 and level 2 hypoglycemia (both P < 0.001).

The analysis identified several modifiable factors associated with postexercise nocturnal hypoglycemia in adults with type 1 diabetes. These findings may support individualized strategies to reduce overnight hypoglycemia risk and improve exercise safety in this population.