Hyperglycemia, Hypoglycemia, Type1diabetes
Conditions
Brief summary
In this study, 14 subjects with type 1 diabetes are studied in a randomized crossover study in which the subjects cycle at a fixed intensity at 60% of their maximum oxygen capacity (VO2 max) for 1 hour. Thirty minutes before each cycling test, participants consume a 200 ml beverage, consisting of either: 1) dextrose (20 g), 2) galactose (20 g), 3) lactose (20 g) or 4) water (sweetened). If blood sugar drops below 3.9 mmol/l, glucose infusion is given and blood sugar is kept just above 5 mmol/L. The trial days take place at least 4 days apart.
Detailed description
On study days, a catheter is placed in two antecubital veins for regular blood sampling and for glucose infusion (if needed). The participant will rest in a bed, when not performing the 1-hour bicycle ergometer test. Thirty minutes before the leg-cycle ergometer test, the participants consume a 300 ml beverage containing either: 1) dextrose (20 g), 2) galactose (20 g) 3) lactose (20 g) or 4) water (sweetened). At t=0, the ergometer test is started and continued for 1 hour (fixed intensity cycling at 60% of VO2-max). If blood glucose drops below 3.9 mmol/l, glucose infusion (5 % glucose) will be administered, and blood glucose is kept just above 5 mmol/l and infused volume is registered. Blood samples are collected at t= -40, 0, 30, 60, 90, 120 for measurement of plasma lactate, non-esterified fatty acids (NEFA), plasma triglyceride and hormonal concentrations (epinephrine, norepinephrine, cortisol, and glucagon). Plasma blood glucose measurements are performed at t = -40 and every 10-15 minutes until the end of the study day. Respiratory exchange ratio is measured by indirect calorimetry (collection of respiratory gasses VO2 and VCO2) pre-exercise, at the end of the exercise bout, and 30 minutes post-exercise. Protein oxidation rate is estimated from urinary urea excretion, and net lipid and glucose oxidation rates are calculated from indirect calorimetry measurements with correction for protein oxidation. Therefor a urine sample will also be collected at the end of the study day. The bicycle ergometer test is discontinued after 1 hour of bicycling and the participant is observed until 2 hour post exercise where the study day is ended.
Interventions
OTHER1-hour cycling
60 % VO2 max
Sponsors
University of Aarhus
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
SINGLE (Subject)
Masking description
The participants will receive either dextrose, water, lactose, galactose in a randomized order (computer generated block randomization) prior to a one-hour exercise bout. Participants, but not investigators, are masked to nutrition allocation.
Intervention model description
The study is a single-blinded, randomized crossover study, consisting of 4 study days of 1-hour fixed intensity cycling, after consumption of either galactose, lactose, glucose or water.
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* type 1 diabetes for at least 2 years * age between 18 and 65 years * HbA1c less than 70 mmol/mol * Physically active (at least 150 minutes of moderate-to-vigorous intensity activity weekly) * Insulin pen and pump treatment * Men and women are eligible, but women will have to perform study days in the mid-cycle phase of the menstrual cycle.
Exclusion criteria
* \- Diabetic nephropathy, neuropathy, and proliferative retinopathy * Hypoglycemia unawareness * Lactose intolerance * Heart disease and other conditions which may be negatively affected by the VO2 max test and 1-hour cycling on study days
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Time to hypoglycemia Secondary endpoints: Blood glucose variability, volume of intravenous glucose needed to maintain glucose above 5 mmol/l, respiratory exchange ratio. | during and 2 hours after the bicycle test | time to blood glucose \< 3.9 mmol/l |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Blood glucose variability | during and 2 hours after the bicycle test | Change in blood glucose (mmol/l) over time |
| Glucose infusion | during and 2 hours after the bicycle test | Volume of intravenous glucose needed to maintain glucose above 5 mmol/l |
| Respiratory exchange ratio | prior, during and 2 hours after the bicycle test | RER is measured to to assess carbohydrate and lipid metabolism |
| Time in Range | prior, during and 2 hours after the bicycle test | Time spend with a blood glucose between 3,9 mmol/l and 10 mmol/l |
Countries
Denmark
Outcome results
None listed