Outcome
Type |
Measure |
Description |
Time frame |
Safety issue |
Primary |
Average 24 hour glucose concentration (at day 4) |
Glucose concentration will be measured in the interstitial fluid of the subcutaneous adipose tissue every 5 min using a glucose sensor (Enlite Glucose Sensor MiniMed; Medtronic) (iPro2 Professional CGM MiniMed; Medtronic, Northridge, CA, USA), which will be inserted subcutaneously, at 5 cm from the umbilicus, on the right side of the abdomen, and will be connected to a continuous glucose monitor (iPro2 Professional CGM MiniMed; Medtronic, Northridge, CA, USA). The cumulative effects of the 4 day exercise regimens will be determined using the average 24h glucose levels collected on day 4. |
Change of average glucose concentration compared to moderate intensity exercise under normoxia (21% oxygen) at day 4 |
|
Secondary |
Glycemic variability over 24 hours |
Moderate intensity exercise under mild hypoxia compared to normoxia. The cumulative effects of the 4 day exercise regimens will be determined using the 24h glucose levels collected on day 4. Glycemic variability, which reflects acute glucose fluctuations, will be assessed by the standard deviation of the average 24 h glucose concentration (SD) |
Change of glycemic variability over 24 hours compared to moderate intensity exercise under normoxia (21% oxygen) at day 2, 3, 4 and 5 |
|
Secondary |
Time in hyper/hypoglycaemia |
Moderate intensity exercise under mild hypoxia compared to normoxia. The cumulative effects of the 4 day exercise regimens will be determined using the 24h glucose levels collected on day 4 frequency and duration of hypo- and hyperinsulinemia will be monitored using the iPro2 device and Enlite Glucose Sensor (Medtronic) and is defined as a glucose level of =10.0 mmol/l for hyperglycemia, whilst hypoglycemia will be defined as a glucose concentration =3.9 mmol/l. |
Change of time spent in hyper/hypoglycemia compared to moderate intensity exercise under normoxia (21% oxygen) at day 2, 3, 4 and 5 |
|
Secondary |
Energy expenditure |
Moderate intensity exercise under mild hypoxia compared to normoxia. Energy expenditure will be determined by means of indirect calorimetry at day 5 (under normoxia in both periods), after 4 consecutive days of performing exercise under normoxia or mild hypoxia. |
Change of energy expenditure compared to moderate intensity exercise under normoxia (21% oxygen) at day 5 during the meal-test |
|
Secondary |
Substrate oxidation |
Moderate intensity exercise under mild hypoxia compared to normoxia. Substrate oxidation (e.g. carbohydrate and fat oxidation) will be determined by means of indirect calorimetry at day 5 (under normoxia in both periods), after 4 consecutive days of performing exercise under normoxia or mild hypoxia. |
Change of substrate oxidation compared to moderate intensity exercise under normoxia (21% oxygen) at day 5 during the meal-test |
|
Secondary |
Systolic and diastolic blood pressure |
Moderate intensity exercise under mild hypoxia compared to normoxia. Every morning, before having breakfast, systolic and diastolic blood pressure will be monitored in mmHg. |
Change of systolic and diastolic blood pressure compared to moderate intensity exercise under normoxia (21% oxygen) at day 1, 2, 3, 4 and 5 under fasting conditions. |
|
Secondary |
HOMA-IR |
Moderate intensity exercise under mild hypoxia compared to normoxia. HOMA-IR will be determined from circulating insulin and glucose levels at sampled at day 5. |
Change of HOMA-IR compared to moderate intensity exercise under normoxia (21% oxygen) at day 5 under fasting conditions |
|
Secondary |
Gene/protein expression of AMPK and phosphorylation of AMPK in skeletal muscle tissue |
Moderate intensity exercise under mild hypoxia compared to normoxia. Skeletal muscle biopsy will be performed at day 5 under fasting conditions and will be analysed for histology and gene/protein expression. Gene expression will be performed by targeted q-PCR (quantitative-polymerase chain reaction), and protein expression will be performed by means of Western blotting to quantify expression of AMPK. |
Change of gene/protein expression of AMPK in skeletal muscle tissue compared to moderate intensity exercise under normoxia (21% oxygen) at day 5, under fasting conditions, when skeletal muscle biopsy will be collected |
|
Secondary |
Systemic concentration of interleukin-8 (IL-8; inflammatory marker) |
Moderate intensity exercise under mild hypoxia compared to normoxia. At day 5, fasting blood will be sampled and analysed for systemic inflammatory markers by means of ELISA |
Change of concentrations of IL-8 compared to moderate intensity exercise under normoxia (21% oxygen) during fasting conditions at day 5 |
|
Secondary |
Systemic concentration of tumor necrosis factor alpha (TNF-alpha; inflammatory marker) |
Moderate intensity exercise under mild hypoxia compared to normoxia. At day 5, fasting blood will be sampled and analysed for systemic inflammatory markers by means of ELISA |
Change of concentrations of TNF-alpha compared to moderate intensity exercise under normoxia (21% oxygen) during fasting conditions at day 5 |
|
Secondary |
Systemic concentration of interferon-gamma (IFN-gamma; inflammatory marker) |
Moderate intensity exercise under mild hypoxia compared to normoxia. At day 5, fasting blood will be sampled and analysed for systemic inflammatory markers by means of ELISA |
Change of concentrations of IFN-gamma compared to moderate intensity exercise under normoxia (21% O2) during fasting conditions at day 5 |
|
Secondary |
Systemic concentration of interleukin-6 (IL-6; inflammatory marker) |
Moderate intensity exercise under mild hypoxia compared to normoxia. At day 5, fasting blood will be sampled and analysed for systemic inflammatory markers by means of ELISA |
Change of concentrations of IL-6 compared to moderate intensity exercise under normoxia (21% oxygen) during fasting conditions at day 5 |
|
Secondary |
Fasting and postprandial plasma glucose concentration |
Moderate intensity exercise under mild hypoxia compared to normoxia. At day 5, fasting and postprandial circulating glucose concentrations (mmol/L) will be determined during a high-carbohydrate mixed-meal test. |
Change of fasting and postprandial plasma glucose concentrations (mmol/L) compared to moderate intensity exercise under normoxia (21% oxygen) at day 5 |
|
Secondary |
Fasting and postprandial plasma insulin concentration |
Moderate intensity exercise under mild hypoxia compared to normoxia. At day 5, fasting and postprandial circulating insulin concentrations (mU/L) will be determined during a high-carbohydrate mixed-meal test. |
Change of fasting and postprandial plasma insulin concentrations (mU/L) compared to moderate intensity exercise under normoxia (21% oxygen) at day 5 |
|
Secondary |
Fasting and postprandial plasma free fatty acids concentration |
Moderate intensity exercise under mild hypoxia compared to normoxia. At day 5, fasting and postprandial circulating free fatty acids concentrations (µmol/L) will be determined during a high-carbohydrate mixed-meal test. |
Change of fasting and postprandial plasma free fatty acids concentrations (µmol/L) compared to moderate intensity exercise under normoxia (21% oxygen) at day 5 |
|
Secondary |
Fasting and postprandial plasma glycerol concentration |
Moderate intensity exercise under mild hypoxia compared to normoxia. At day 5, fasting and postprandial circulating glycerol (µmol/L) will be determined during a high-carbohydrate mixed-meal test. |
Change of fasting and postprandial plasma glycerol concentrations (µmol/L) compared to moderate intensity exercise under normoxia (21% oxygen) at day 5 |
|
Secondary |
Fasting and postprandial plasma triglycerides concentration |
Moderate intensity exercise under mild hypoxia compared to normoxia. At day 5, fasting and postprandial circulating triglycerides (µmol/L) will be determined during a high-carbohydrate mixed-meal test. |
Change of fasting and postprandial plasma triglycerides concentrations (µmol/L) compared to moderate intensity exercise under normoxia (21% oxygen) at day 5 |
|
Secondary |
Fasting and postprandial plasma lactate concentration |
Moderate intensity exercise under mild hypoxia compared to normoxia. At day 5, fasting and postprandial circulating lactate (mmol/L) will be determined during a high-carbohydrate mixed-meal test. |
Change of fasting and postprandial plasma lactate concentrations (mmol/L) compared to moderate intensity exercise under normoxia (21% oxygen) at day 5 |
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