Inter- and Intraindividual Variability of the Acute Glucose Response to Exercise in Healthy Adults and People Living With Type 1 Diabetes: A Cross-over Replicate Trial

NCT07209930 | Recruiting

• 2 other identifiers: LS-24-26-Merlo-HornerEBPPG/2023/627
• Study Type: interventional
• Target: 24
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to investigate if blood glucose responses are similar between and within individuals in response to standardized exercise in adults with and without Type 1 diabetes. The main questions it aims to answer are: What is the reproducibility of acute glycaemic responses to exercise within and between subjects in adults living with Type 1 Diabetes and in healthy adults? What is the agreement between glucose levels obtained by continuous glucose monitor (CGM) and blood glucose monitor? Participants will cycle on a cycle ergometer or rest after consuming a standardized breakfast, while glucose levels are monitored by CGM and capillary blood sampling.

Conditions

Exercise; Healthy Participants; Glucose Variability; Type 1 Diabetes (T1D)

Keywords

reproducibility; exercise; Type 1 diabetes; glucose

Outcome Measures

Primary Outcomes (2)

• Interstitial glucose

  Interstitial glucose values (mmol/l) collected via Freestyle libre 2 Continuous Glucose Monitor

  Over 2 hours: 2 samples at baseline in the fasted state before breakfast consumption; and every 5 minutes following breakfast for 2 hours.

• Capillary glucose

  Capillary glucose was measured via finger prick using a blood glucose monitor.

  2 hours: (1) at baseline before breakfast consumption; (2) every 10 minutes over 30 minutes after breakfast consumption during rest; (3) every 5 minutes for 30 minutes during cycle or seated rest based on intervention; (4) every 10 minutes for 60 min.

Secondary Outcomes (3)

• Heart-rate variability

  2 hours: (1) at baseline before breakfast consumption. (2) every 10 minutes for 120 minutes. (3) extra measurements of HR only were taken during the second thirty minutes, resulting in HR measurements at 5-minutes intervals during that time-frame.

• Perception of symptoms of Hypoglycaemia.

  2 hours: (1) at baseline before breakfast consumption; (2) every 20 minutes for 120 minutes.

• Reporting of Perceived Exortion (RPE)

  1 hour: (1) at baseline before breakfast consumption; (2) every 5 minutes during the second half hour.

Study Arms (2)

Exercise and Rest

EXPERIMENTAL

At the first test visit participants will complete 30 minutes exercise on a cycle ergometer, and at the second visit they will remain at rest. Identical conditions in an identical order will be repeated the following week.

Other: Exercise; Other: Rest

Rest and Exercise

EXPERIMENTAL

At the first test visit participants will remain at rest and at the second visit they will complete 30 minutes exercise on a cycle ergometer. Identical conditions in an identical order will be repeated the following week.

Other: Exercise; Other: Rest

Interventions

Exercise OTHER

After a 12h overnight fast, baseline measurements are collected. Participants are then provided with a standardized breakfast meal (60g carbohydrate). After consumption of the breakfast, participants remain seated seated for 30 minutes, before cycling on a cycle ergometer for 30 minutes at an intensity equivalent to 10% above the first ventilatory threshold (VT1). Sixty minutes of rest sitting on a chair will follow the 30-minute cycle. During the total 120 minute test, various measurements are collected at regular intervals, including: blood glucose measurements via finger prick, CGM measurements, RPE, HR, measures of heart rate variability (HRV) (RMSSD (Root Mean Square of Successive Differences) and SDNN (Standard Deviation of NN intervals)), and intensity of any hypoglycaemia-related symptoms using a Visual Analogue Scale (VAS).

Exercise and Rest; Rest and Exercise

Rest OTHER

The procedure for the resting condition visits is identical to that of the exercise condition, with the only difference being that the 30-minute cycling session will be replaced by an additional 30 minutes of seated rest. This will ensure that the total duration of the session and the timing of all measurements will remain consistent across conditions.

Exercise and Rest; Rest and Exercise

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• (Healthy and T1D phases):
• age between 18 and 60 years old;
• being healthy individuals;
• engagement in physical activity at least once a week; (T1D phase):
• diagnosis of T1D for \>18 months;
• hypoglycaemia self awareness.

You may not qualify if:

• (Healthy and T1D phases)
• presence of cardiovascular disease or contraindications to exercise;
• infectious or inflammatory conditions;
• chronic renal or liver disease;
• pregnancy;
• gestational diabetes;
• diagnosed eating disorders;
• any physical or mental condition preventing participation; (Healthy phase)
• diabetes mellitus (type 1 or type 2); (T1D phase)
• inability to self-manage diabetes.

Sponsors & Collaborators

• University College Dublin: lead
• Taighde Éireann - Research Ireland: collaborator
• Irish Research Council: collaborator

Study Sites (1)

University College Dublin

Dublin, Dublin, D04 V1W8, Ireland

RECRUITING

MeSH Terms

Conditions

Motor Activity; Diabetes Mellitus, Type 1

Interventions

Exercise; RE1-silencing transcription factor

Condition Hierarchy (Ancestors)

Behavior; Diabetes Mellitus; Glucose Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Endocrine System Diseases; Autoimmune Diseases; Immune System Diseases

Intervention Hierarchy (Ancestors)

Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena

Central Study Contacts

Veronica Merlo

CONTACT

3458479939; veronica.merlo@ucdconnect.ie

Katy Horner

CONTACT

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Replicate crossover design

Study Record Dates

• First Submitted: September 29, 2025
• First Posted: October 7, 2025
• Study Start: January 28, 2025
• Primary Completion: December 31, 2025
• Study Completion (Estimated): July 31, 2026
• Last Updated: October 7, 2025

Record last verified: 2025-08

Data Sharing

• IPD Sharing: Will not share

Locations

IE (1)