How menstrual cycle phases affect blood sugar during aerobic and HIIT exercise in women with Type 1 diabetes.

Influence of Menstrual Cycle Phases on the Glycemic Control of Aerobic or HIIT Exercise in Adult Women With Type 1 Diabetes (DIABETEXX/2)

This study will test whether blood sugar responds differently to aerobic exercise versus high-intensity interval training at different menstrual cycle phases in adult women with Type 1 diabetes.

Quick facts

• Phase: NA
• Study type: Interventional
• Enrollment: 40 (estimated)
• Ages: 18 Years to 45 Years
• Sex: Female
• Sponsor: University of Valencia (other)
• Locations: 1 site (Valencia, Select One)
• Trial ID: NCT06729242 on ClinicalTrials.gov

What this trial studies

The study uses continuous glucose monitors to record blood glucose responses in adult women with Type 1 diabetes during standardized aerobic and high-intensity interval training sessions. Sessions will be scheduled in different menstrual cycle phases to compare glucose behavior for each exercise type and phase. Researchers will model glucose trajectories and insulin adjustments to identify patterns linked to cycle phases. Results will be used to create exercise programming guidelines and to inform artificial pancreas algorithms that account for menstrual-cycle effects.

Who should consider this trial

Good fit: Ideal candidates are menstruating women aged 18–45 with Type 1 diabetes for more than 2 years, HbA1c under 8.5%, a stable insulin regimen (MDI or pump) for the past 6 months, and who do at least 90 minutes of weekly physical activity but are not competitive athletes.

Not a fit: Women who are not menstruating (including post‑menopausal or pregnant), those using medications that affect glycemia (e.g., systemic steroids or metformin), or with unstable insulin dosing or HbA1c above 8.5% are less likely to benefit from this protocol.

Why it matters

Potential benefit: If successful, the results could help personalize exercise advice and improve glucose control for menstruating women with Type 1 diabetes and inform better artificial pancreas settings.

How similar studies have performed: Small prior studies suggest menstrual phase can change glucose responses to exercise, but direct comparisons of aerobic versus HIIT across cycle phases and incorporation into closed‑loop systems remain limited and partly novel.

Eligibility criteria

Inclusion Criteria:

Age between 18-45 years T1D with a diabetes duration for more than 2 years Glycated hemoglobin (HbA1c) \< 8.5% (\<69 mmol mol-1) Stable insulin regimen in the past 6 months with less than 20% change in total insulin daily dose Multiple daily injections or insulin pump Weekly physical activity of 90 min or more, but no practicing any sport as amateur or professional.

Exclusion Criteria:

Clinical conditions or use of medications (other than insulin) known to affect glycemic control (e.g., oral/parenteral steroids or metformin, among others).

Where this trial is running

Valencia, Select One

• University of Valencia — Valencia, Select One, Spain (RECRUITING)

Study contacts

• Study coordinator: Rodrigo Martín-San Agustín, Dr.

Conditions: Diabetes Mellitus, Type I, Menstruation