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.
age between 18 and 60 years old;
being healthy individuals;
diagnosis of T1D for >18 months;
hypoglycaemia self awareness.
presence of cardiovascular disease or contraindications to exercise;
infectious or inflammatory conditions;
chronic renal or liver disease;
pregnancy;
Crossover
Exercise
Other interventionAfter 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).
Rest
Other interventionThe 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.
Interstitial glucose
Interstitial glucose values (mmol/l) collected via Freestyle libre 2 Continuous Glucose Monitor
Capillary glucose
Capillary glucose was measured via finger prick using a blood glucose monitor.
Heart-rate variability
Measures of heart rate variability including HR, RMSSD and SSND were collected using polar monitors and chest straps.
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.
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.
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University College Dublin
Lead sponsor
Taighde Éireann - Research Ireland
Collaborator
Irish Research Council
Collaborator
