Skeletal Muscle Energetics
Conditions
Brief summary
This study examines the impact of increasing energetic stress during an 8-hour fast on metabolic pathways in human skeletal muscle. Specifically, participants will undergo two 8-hour fasting sessions in a randomized crossover fashion, with the addition of low-intensity arm exercise in one of the sessions. Changes in metabolic pathways will be examined in resting (leg) muscle before, during, and after the fast.
Interventions
OTHERFAST+EX
Participants will perform 2-hours of low-intensity arm exercise (8 x 15 min bouts of arm ergometer exercise separated by 10 min of rest) during an 8-hour fast.
OTHERFAST
Participants will complete an 8-hour fast.
Sponsors
University of Waterloo
Queen's University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Investigator, Outcomes Assessor)
Masking description
Allocation concealment, assessor blinding
Eligibility
Sex/Gender
MALE
Age
18 Years to 30 Years
Healthy volunteers
Yes
Inclusion criteria
* recreationally active (no more than 3 hours of weekly physical activity) * not currently involved in a systematic training program * body mass index \< 30 kg/m2
Exclusion criteria
* presence of cardiometabolic disease * taking regular oral medication * current smoker
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Peroxisome proliferator activated receptor gamma co-activator 1-alpha (PGC-1α) messenger ribonucleic acid (mRNA) expression | 15 min before fast; after 4 and 8 hours of fasting | PGC-1α gene expression (indirect indicator of PGC-1α activity) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Glucose and insulin concentrations | 15 min before fast; after 4 and 8 hours of fasting | Glucose and insulin concentrations in plasma samples |
| total and phosphorylated AMP activated protein kinase (AMPK) | 15 min before fast; after 4 and 8 hours of fasting | active AMPK relative to total AMPK protein content |
| total and phosphorylated SIRT-1 | 15 min before fast; after 4 and 8 hours of fasting | active SIRT-1 relative to total SIRT1 protein content |
| total and phosphorylated mammalian target of rapamycin (mTOR) | 15 min before fast; after 4 and 8 hours of fasting | active mTOR relative to total mTOR protein content |
| total and phosphorylated Akt/Protein Kinase B | 15 min before fast; after 4 and 8 hours of fasting | active Akt relative to total Akt protein content |
| total and phosphorylated acetyl coenzyme A carboxylase (ACC) | 15 min before fast; after 4 and 8 hours of fasting | active ACC relative to total ACC protein |
| total and phosphorylated p38 mitogen activated protein kinase (MAPK) | 15 min before fast; after 4 and 8 hours of fasting | active p38 MAPK relative to total p38 MAPK protein |
| phosphorylated protein kinase A (PKA) substrates | 15 min before fast; after 4 and 8 hours of fasting | phosphorylated PKA substrates (indirect measure of PKA activity) |
| acetylated p53 | 15 min before fast; after 4 and 8 hours of fasting | p53 acetylation status (indirect measure of SIRT-1 deacetylase activity) |
| Catecholamine concentrations | 15 min before fast; after exercise; after 4 and 8 hours of fasting | Epinephrine and norepinephrine concentrations in plasma samples |
| Sirtuin 3 (SIRT3) mRNA expression | 15 min before fast; after 4 and 8 hours of fasting | gene expression of the deacetylase enzyme SIRT3 |
| Pyruvate dehydrogenase kinase isoenzyme 4 (PDK4) mRNA expression | 15 min before fast; after 4 and 8 hours of fasting | gene expression of the PGC-1α target PDK4 |
| p53 mRNA expression | 15 min before fast; after 4 and 8 hours of fasting | gene expression of the tumour suppressor protein p53 |
| Leucine rich pentatricopeptide repeat containing protein (LRP130) mRNA expression | 15 min before fast; after 4 and 8 hours of fasting | gene expression of RNA-binding protein LRP130 |
| General control non-repressible 5 (GCN5) mRNA expression | 15 min before fast; after 4 and 8 hours of fasting | gene expression of the acetyltransferase GCN5 |
| PGC-1α protein content | 15 min before fast; after 4 and 8 hours of fasting | Protein content of the transcriptional co-activator PGC-1α |
| Cytochrome C oxidase subunit 4 (COX-IV) protein content | 15 min before fast; after 4 and 8 hours of fasting | Protein content of the mitochondrial enzyme COX subunit 4 |
| Intramuscular glycogen content | 15 min before fast; after 4 and 8 hours of fasting | Muscle glycogen content |
| Intramuscular triglyceride (IMTG) content | 15 min before fast; after 4 and 8 hours of fasting | Muscle IMTG content |
| Sirtuin 1 (SIRT1) mRNA expression | 15 min before fast; after 4 and 8 hours of fasting | gene expression of the deacetylase enzyme SIRT1 |
Countries
Canada
Outcome results
None listed