Hyperglycemia, Insulin Sensitivity
Conditions
Brief summary
For decades, it has been known that post-meal blood glucose concentrations were associated with the risk of T2D, which was reflected in early diagnostic guidelines. The oral glucose tolerance test (OGTT) has been used since at least 1923 and has remained the most common test for assessing glucose tolerance. Arterial blood (or arterialised blood using heated hand technique) is most appropriate for determining glucose tolerance and insulin sensitivity since this best represents the concentrations of metabolites and hormones that peripheral tissues are exposed to. It is essential to investigate whether venous blood (sometimes used during an OGTT) is representative of arterialised blood during an OGTT, and under different metabolic conditions. The investigators want to understand whether OGTT-derived insulin sensitivity indices differ from venous and arterialised blood; and 2) investigate whether metabolic status (i.e. rest vs lower-limb exercise) influences the difference between forearm venous and arterialised concentrations of glucose and insulin during an OGTT.
Interventions
BEHAVIORALRest
Allowed to watch television or read for one hour prior to oral glucose tolerance test
BEHAVIORALExercise
One hour of cycling at 50% of maximal power output
OTHERDorsal Hand Vein Cannulation (heated hand technique)
OTHERVenous Cannulation
Sponsors
University of Bath
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
MALE
Age
18 Years to 49 Years
Healthy volunteers
Yes
Inclusion criteria
* Aged 18-49 years * Able and willing to safely comply with all study procedures * Able to provide written informed consent for participation
Exclusion criteria
* Diagnosis of any bleeding disorder or taking medication which impacts blood coagulation * The presence of any contraindications to maximal exercise testing, as determined using a physical activity readiness questionnaire (PAR-Q). * Any diagnosis of metabolic disease (i.e. cardiovascular disease or type 2 diabetes).
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Postprandial plasma glucose concentrations (area under the concentration-time curve) | 120 mins |
| OGTT-derived insulin sensitivity | 120 mins |
Secondary
| Measure | Time frame |
|---|---|
| Fasting plasma lactate concentrations | 5 mins |
| Fasting plasma triglyceride concentrations | 5 mins |
| Postprandial plasma lactate concentrations (area under the concentration-time curve) | 120 mins |
| Fasting plasma glucose concentrations | 5 mins |
| Substrate utilization for energy provision | 180 mins |
| Postprandial plasma insulin concentrations (area under the concentration-time curve) | 120 mins |
| Postprandial plasma triglyceride concentrations (area under the concentration-time curve) | 120 mins |
| Fasting plasma insulin concentrations | 5 mins |
Countries
United Kingdom
Outcome results
None listed