ExerciseNCT07209930
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
A study testing Exercise and Rest in people with Exercise and Healthy Participants, run by University College Dublin at 1 site in Ireland.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Exercise, Healthy Participants, Glucose Variability
- What is being tested?
- Exercise and Rest
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 24 participants
- Where
- 1 siteIreland
- Study dates
- 28 Jan 2025to 31 Jul 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- (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.
Who cannot join
- (Healthy and T1D phases)
- presence of cardiovascular disease or contraindications to exercise;
- infectious or inflammatory conditions;
- chronic renal or liver disease;
- pregnancy;
- gestational diabetes;
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- 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.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Katy Horner contact
Ireland1 site, 1 recruiting
- Recruiting
University College Dublin
Dublin, Dublin, D04 V1W8
Veronica Merlo, 3458479939 ext. +39, veronica.merlo@ucdconnect.ie
About this study
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.
Read the detailed description
This study follows a non-blinded randomized replicate crossover study design. The study involves two phases, one phase will involve participants with T1D and the other phase will involve healthy adults. The sample size will be approximately 12 in each phase. Both phases will follow the same protocol consisting of 2 arms (exercise (EX) and rest).
Participants will attend 5 visits in total in the laboratory. They will first undergo baseline assessments and maximal exercise testing before being randomized to receive either an exercise (EX) or resting (REST) condition at their visit first. The two visits will then repeated to assess reproducibility of the outcomes in the same order the following week (EX RE and REST RE). All test visits will be separated by a minimum washout period of 72 hours.
The first visit will last approximately 1 hour and involves signing informed consent, body composition assessment (BodPod), maximal exercise testing (Vo2 max) and completion of questionnaires.
Before each condition, participants are asked to refrain from strenuous physical activity and alcohol for at least 24 hours prior to the test(s). Prior to the first main testing day (either EX or RE based on randomization), participants are asked to record their dietary intake for 24h and asked to replicate it in the same period before the subsequent conditions.
Testing visits have a duration of 2 hours each. Participants will arrive at the laboratory after an overnight fast always at the same time in the morning (about 9am). While seated, baseline measurements will be collected, including 2 blood glucose measurements via finger prick, 2 CGM measurements, RPE, HR, measures of heart rate variability (HRV), and participants will the intensity of any hypoglycaemia-related symptoms using a Visual Analogue Scale (VAS). The same measurements will be repeated at regular intervals throughout the visit.
Participants were then provided with a standardized breakfast meal (60g of CHO) that they were instructed to consume within 10 minutes. After consumption of the breakfast, a clock was started. Participants remained seated for 30 minutes, and - during the EX condition - cycled on a cycle ergometer for 30 minutes at an intensity equivalent to 10% above VT. Sixty minutes of rest sitting on a chair follow the 30-minute cycle, before participants can leave the laboratory.
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 is replaced by an additional 30 minutes of seated rest. This ensures that the total duration of the session and the timing of all measurements remains consistent across conditions.
- Being tested
- Exercise, Rest
- Keywords
- reproducibility, exercise, Type 1 diabetes, glucose
- Medical subject headings
- Motor Activity, Diabetes Mellitus, Type 1
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ExerciseOther
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).
RestOther
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.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: Other: Exercise; Other: Rest |
What is being measured
The primary outcome is the main question the study is designed to answer.
Interstitial glucose
Interstitial glucose values (mmol/l) collected via Freestyle libre 2 Continuous Glucose Monitor
Measured: 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.
Measured: 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
Measures of heart rate variability including HR, RMSSD and SSND were collected using polar monitors and chest straps.
Measured: 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.
100 millimetre Visual Analogue Scales (VAS) will be used. This VAS has anchors located at each end of the scale. On the left end of the scale (0 mm), the "not at all" response is represented, while the right end (100 mm) represents the "extremely" response. Participants mark along the line where it most represents their subjective perception of 7 individual symptoms of hypoglycaemia (sweatiness; anxiety; hunger; thirst; difficulties in concentrating; blurred vision; dizziness) between both ends.
Measured: 2 hours: (1) at baseline before breakfast consumption; (2) every 20 minutes for 120 minutes.
Reporting of Perceived Exortion (RPE)
Ratings of Perceived Exertion (RPE) were collected using the Borg 6-20 Scale. Participants were initially familiarised with the scale during their baseline visit to ensure proper understanding.
Measured: 1 hour: (1) at baseline before breakfast consumption; (2) every 5 minutes during the second half hour.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Oct 2025
- Study start28 Jan 2025
- Primary completion31 Dec 2025 (estimated)
- Study completion31 Jul 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ExerciseStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Replicate crossover design
- Masking
- None (open label)
- Enrolment
- 24 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University College Dublin
- Sponsor type
- University, hospital or other
- Collaborators
- Taighde Éireann - Research Ireland, Irish Research Council
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07209930
- Sponsor's protocol ID
- LS-24-26-Merlo-Horner
- Other IDs
- EBPPG/2023/627
- Status last verified
- Aug 2025
- First submitted
- 29 Sep 2025
- Last updated
- 7 Oct 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: It is not approved within the ethics application to share IPD.
Study at a glance
From the registry record, last updated by the sponsor on 7 Oct 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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
- ClinicalTrials.gov ID
- NCT07209930
- Acronym / sponsor ID
- LS-24-26-Merlo-Horner
- Keywords
- reproducibility, exercise, Type 1 diabetes, glucose
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 24 participants (estimated)
- Lead sponsor
- University College DublinUniversity, hospital or other
- Collaborators
- Taighde Éireann - Research Ireland, Irish Research Council
- Study start
- 28 Jan 2025 (actual)
- Primary completion
- 31 Dec 2025 (estimated)
- Study completion
- 31 Jul 2026 (estimated)
- First posted
- 7 Oct 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
This study follows a non-blinded randomized replicate crossover study design. The study involves two phases, one phase will involve participants with T1D and the other phase will involve healthy adults. The sample size will be approximately 12 in each phase. Both phases will follow the same protocol consisting of 2 arms (exercise (EX) and rest).
Participants will attend 5 visits in total in the laboratory. They will first undergo baseline assessments and maximal exercise testing before being randomized to receive either an exercise (EX) or resting (REST) condition at their visit first. The two visits will then repeated to assess reproducibility of the outcomes in the same order the following week (EX RE and REST RE). All test visits will be separated by a minimum washout period of 72 hours.
The first visit will last approximately 1 hour and involves signing informed consent, body composition assessment (BodPod), maximal exercise testing (Vo2 max) and completion of questionnaires.
Before each condition, participants are asked to refrain from strenuous physical activity and alcohol for at least 24 hours prior to the test(s). Prior to the first main testing day (either EX or RE based on randomization), participants are asked to record their dietary intake for 24h and asked to replicate it in the same period before the subsequent conditions.
Testing visits have a duration of 2 hours each. Participants will arrive at the laboratory after an overnight fast always at the same time in the morning (about 9am). While seated, baseline measurements will be collected, including 2 blood glucose measurements via finger prick, 2 CGM measurements, RPE, HR, measures of heart rate variability (HRV), and participants will the intensity of any hypoglycaemia-related symptoms using a Visual Analogue Scale (VAS). The same measurements will be repeated at regular intervals throughout the visit.
Participants were then provided with a standardized breakfast meal (60g of CHO) that they were instructed to consume within 10 minutes. After consumption of the breakfast, a clock was started. Participants remained seated for 30 minutes, and - during the EX condition - cycled on a cycle ergometer for 30 minutes at an intensity equivalent to 10% above VT. Sixty minutes of rest sitting on a chair follow the 30-minute cycle, before participants can leave the laboratory.
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 is replaced by an additional 30 minutes of seated rest. This ensures that the total duration of the session and the timing of all measurements remains consistent across conditions.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Replicate crossover design
| Arm | Type | Receives |
|---|---|---|
| Exercise and Rest | Experimental | Other: Exercise, Other: RestAt 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. |
| Rest and Exercise | Experimental | Other: Exercise, Other: RestAt 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. |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- 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.
Key exclusion criteria (10 listed)
- (Healthy and T1D phases)
- presence of cardiovascular disease or contraindications to exercise;
- infectious or inflammatory conditions;
- chronic renal or liver disease;
- pregnancy;
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ExerciseAfter 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). | Other | Exercise and Rest, Rest and Exercise |
| RestThe 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. | Other | Exercise and Rest, Rest and Exercise |
Primary outcome
Interstitial glucose
Time frame: Over 2 hours: 2 samples at baseline in the fasted state before breakfast consumption; and every 5 minutes following breakfast for 2 hours.
Interstitial glucose values (mmol/l) collected via Freestyle libre 2 Continuous Glucose Monitor
Capillary glucose
Time frame: 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.
Capillary glucose was measured via finger prick using a blood glucose monitor.
3 secondary outcomes
Heart-rate variability
Time frame: 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.
Time frame: 2 hours: (1) at baseline before breakfast consumption; (2) every 20 minutes for 120 minutes.
Reporting of Perceived Exortion (RPE)
Time frame: 1 hour: (1) at baseline before breakfast consumption; (2) every 5 minutes during the second half hour.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Oct 2025.
- Individual participant dataSharing planned: No. It is not approved within the ethics application to share IPD.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Katy Horner contact
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Exercise and Rest in people with Exercise and Healthy Participants, run by University College Dublin at 1 site in Ireland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 7 Oct 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Ireland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Veronica Merlo (3458479939 ext. +39, veronica.merlo@ucdconnect.ie), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Interstitial glucose (time frame: Over 2 hours: 2 samples at baseline in the fasted state before breakfast consumption; and every 5 minutes following breakfast for 2 hours.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Oct 2025.