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Blood glucose response during cardiopulmonary exercise testing in individuals with type 1 diabetes / BENJAMIN WELLMAN

Swansea University Author: BENJAMIN WELLMAN

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Abstract

To characterise blood glucose responses in cardiopulmonary exercise testing (CPET) in individuals with type 1 diabetes and to assess the impact of hyperglycaemia vs euglycemia on physiological and metabolic responses during CPET in T1DM. This study was a retrospective, secondary analysis of pooled C...

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Published: Swansea, Wales, UK 2022
Institution: Swansea University
Degree level: Master of Research
Degree name: MSc by Research
Supervisor: Bracken, R. M.
URI: https://cronfa.swan.ac.uk/Record/cronfa63571
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Abstract: To characterise blood glucose responses in cardiopulmonary exercise testing (CPET) in individuals with type 1 diabetes and to assess the impact of hyperglycaemia vs euglycemia on physiological and metabolic responses during CPET in T1DM. This study was a retrospective, secondary analysis of pooled CPET data from three randomised controlled trials using identical 1-minute incremental test stages. Participants followed standardised glycaemic management criteria prior to exercise. During CPX testing, cardiopulmonary variables were measured continuously whilst blood glucose (BG) and lactate values were obtained minutely via capillary earlobe sampling. Anaerobic threshold (AT) was determined using the modified V-slope index by the ventilatory equivalents for CO2 and O2 (VE/VCO2, VE/VCO2), expressed as a function of VO2. Data were reported as mean±SD and analysed by a students paired t-test with p≤0.05. Data from 36 individuals with T1DM HbA1c 7.3±1.1%, age 32±13 years, diabetes duration 17±10 years, maximum heart rate 180±13 bpm and V̇ O2max of 3.2±0.9 L.min-1 were included. BG values remained equivalent to sitting concentrations (8.91±2.47 mmol.L-1) at each stage of the CPET protocol. The change in BG above the anaerobic threshold was differently significantly from the change in BG below the AT (Sit–AT; +0.2±0.7 vs. AT-Peak; -0.5±0.8 mmol.L-1, [i.e. Δ 0.7], p<0.001). The rate of change (ROC) between values showed that the change in the ROC from Sit-AT to AT-Peak was significantly different between groups (Sit-AT; Δ0.004±0.06 vs. AT-Peak; Δ-0.049±0.10 mmol.L-1 , p=0.01). Between Hyperglycaemia (Hyper) vs. Euglycemia (Eu), BG remained comparable within each respective starting BG levels. The magnitude of change in BG from Sit-AT was significantly differentbetween groups (Hyper Δ-0.09±0.35 vs. Eu Δ+0.32±0.76 p=0.030). Hyper from Sit-AT had a significantly different magnitude in the ROC to AT-Peak (-0.04±-0.06 mmol.L-1/min, p=0.032) but not in the Eu group. We found that under correct CPET protocol, glycaemia is minimally disturbed and does not result in hypoglycaemia or changes in performance outcomes. However, starting exercise with high blood glucose levels (hyperglycaemia) impacts some cardio-metabolic outcomes during maximal and recovery phases around CPET.
Keywords: Type 1 Diabetes, Glucose, Glycemia, Cardiopulmonary Exercise Test, CPEX
College: Faculty of Science and Engineering
Funders: Swansea University