Glucose Metabolism Disorders
Conditions
Keywords
Exercise, Fasted, Glucose, Energy Balance
Brief summary
In healthy individuals, the body responds to glucose (sugar) ingestion by reducing the amount released from the liver. At the same time, skeletal muscles increase the rate at which they remove the glucose from the bloodstream, via the actions of the hormone insulin. This ensures that blood glucose levels remain in a controlled range. However, in developed countries, diseases such as metabolic syndrome and type 2 diabetes are becoming prevalent, due to dietary modifications and a reduction in physical activity. As one of the prominent barriers to regular physical activity is a lack of time, finding ways to maximize the health benefits of exercise is a priority for researchers. The investigators want to understand potential differences in the effects of six weeks of aerobic training, with the exercise performed either after breakfast or after a prolonged fast. Specifically, this research aims to investigate whether there is a difference in the change in processes implicated in glucose regulation and secondly, in subsequent eating and physical activity behaviors. By investigating these changes this work will explore how exercise and nutrition can be optimized to benefit health and weight loss.
Interventions
BEHAVIORALExercise
Moderate intensity exercise
BEHAVIORALBreakfast
Breakfast consumption
BEHAVIORALMaintain habitual habits
Normal physical activity and dietary behaviors maintained
Sponsors
University of Bath
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
MALE
Age
18 Years to 49 Years
Healthy volunteers
Yes
Inclusion criteria
* Male * Aged 18-49 * Body mass index (BMI) \> 25 kg/m2 * Weight stable for \> 6 months * Not currently engaging in any form of structured exercise * Be able and willing to give informed oral and written consent * Complete and meet the defined criteria of pre-study questionnaires and screen
Exclusion criteria
* Have a history of metabolic, cardio-pulmonary or musculoskeletal disease * Have plans to change diet and/or physical activity outside of the intervention * Taking regular medication or food supplements from which it is not possible to refrain and which are known to influence any of the outcome measures. * Failure to refrain from alcohol and/or caffeine containing drinks or strenuous exercise one day before or during the trial days * Smokers * Any reported condition or behavior deemed to pose a risk to the participant or introduce bias into the experiment
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Postprandial plasma glucose concentrations | 120 mins - (change after 6 weeks) | Response to oral glucose tolerance test (area under the curve) |
| Postprandial insulin concentrations | 120 mins - (change after 6 weeks) | Response to oral glucose tolerance test (area under the curve) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Cardiorespiratory fitness (VO2max) | Change after 6 weeks | — |
| Habitual energy intake | Change after 6 weeks | Assessed via a food diary, completed at baseline and during the last week of the intervention |
| Habitual energy expenditure | Change after 6 weeks | Assessed via an Actiheart monitor, completed at baseline and during the last week of the intervention |
| Body mass (kg) | Change after 6 weeks | — |
| Waist and hip circumference (cm) | Change after 6 weeks | — |
| Maximal rate of whole-body lipid oxidation (g/min) | Change after 6 weeks | During an incremental exercise test |
| Fasting plasma glucose concentration | Basal Concentrations - (change after 6 weeks) | Fasting plasma glucose concentration (mmol/L) |
| Fasting plasma insulin concentration | Basal Concentrations - (change after 6 weeks) | Fasting plasma insulin concentration (pmol/L) |
| Whole-body lipid utilisation during exercise | Change throughout complete training period (weeks 1 through to 6). Samples will be collected during every training session (three times weekly for six weeks) | Assessed via indirect calirometry during every exercise session (at ten minute intervals) |
| Postprandial non-esterified fatty acid concentrations | 120 mins - (change after 6 weeks) | Response to oral glucose tolerance test (total and incremental area under the curve) |
| Fasting plasma triglyceride concentrations | Basal Concentrations - (change after 6 weeks) | Fasting plasma triglyceride concentrations (mmol/L) |
| Fasting plasma total cholesterol concentrations | Basal Concentrations - (change after 6 weeks) | Fasting plasma total cholesterol concentrations (mmol/L) |
| Fasting plasma HDL cholesterol concentrations | Basal Concentrations - (change after 6 weeks) | Fasting plasma HDL cholesterol concentrations (mmol/L) |
| Energy balance | Change after 6 weeks (during week 6 of intervention versus baseline monitoring) | Total energy expenditure minus total energy intake |
| Fasting plasma non-esterified fatty acid concentrations | Basal Concentrations - (change after 6 weeks) | Fasting plasma non-esterified fatty acid concentrations (mmol/L) |
| Waist to hip ratio | Change after 6 weeks | Waist circumference (cm) divided by hip circumference (cm) |
| Citrate Synthase Activity (mitochondrial citrate synthase activity in each muscle sample in an immunocapture based manner) | Change after 6 weeks | Skeletal muscle (vastus lateralis). Citrate Synthase Activity Assay Kit. |
| Protein content of mitochondrial respiratory chain proteins | Change after 6 weeks. For each participant the protein content will be presented as the fold change from baseline (arbitrary units). | Skeletal muscle (vastus lateralis). Complex I, Complex II, Complex III, Complex IV. |
| Protein content of carnitine palmitoyltransferase I (CPT-1) | Change after 6 weeks. For each participant the protein content will be presented as the fold change from baseline (arbitrary units) | Skeletal muscle (vastus lateralis) |
| Protein content of cluster of differentiation 36 (CD36) | Change after 6 weeks. For each participant the protein content will be presented as the fold change from baseline (arbitrary units) | Skeletal muscle (vastus lateralis) |
| Protein content (total and phosphorylated form) of AMP-activated protein kinase (AMPK) | Change after 6 weeks. For each participant the protein content will be presented as the fold change from baseline (arbitrary units) | Skeletal muscle (vastus lateralis) |
| Resting metabolic rate (RMR) | Change after 6 weeks | Assessed via indirect calirometry |
| Whole-body carbohydrate utilisation during exercise | Change throughout complete training period (weeks 1 through to 6). Samples will be collected during every training session (three times weekly for six weeks) | Assessed via indirect calirometry during every exercise session (at ten minute intervals) |
| Homeostasis Model Assessment (HOMA2-IR) | Change after 6 weeks | The Homeostasis Model Assessment (HOMA) estimate of steady state beta cell function (%B) and insulin sensitivity (%S). Derived from fasting plasma glucose and fasting plasma insulin concentrations. |
| Fasting plasma glycerol concentrations | Basal Concentrations - (change after 6 weeks) | Fasting plasma glycerol concentrations (mmol/L) |
| Postprandial plasma glycerol concentrations | Change after 6 weeks | Response to oral glucose tolerance test (total and incremental area under the curve) |
| Adipose Tissue Insulin Resistance Index (Adipo-IR) | Change after 6 weeks | Response to oral glucose tolerance test (total and incremental area under the curve) |
| Fasting plasma LDL cholesterol concentrations | Basal Concentrations - (change after 6 weeks) | Fasting plasma LDL cholesterol concentrations (mmol/L) |
| Oral Glucose Insulin Sensitivity Index | 120 mins - (change after 6 weeks) | Response to oral glucose tolerance test |
Countries
United Kingdom
Outcome results
None listed