Two weeks of reduced-volume sprint interval or traditional exercise training does not improve metabolic functioning in sedentary obese men

Aims: To investigate the effects of short-term, reduced-volume sprint interval training (SIT) compared to traditional exercise recommendations (TER) in sedentary obese men.

Methods: Sixteen subjects [37.8±5.8years; body mass index (BMI) 32.8±4.7kg/m²] were randomly allocated to 2weeks of either SIT (6 sessions of 8-12×10s sprints) or TER [10 sessions of 30min at 65% peak oxygen consumption (VO_2peak)] cycle exercise. Fasting plasma glucose, insulin, non-esterified fatty acids (NEFA), homeostasis model assessment of insulin sensitivity (HOMA-IR), body composition and VO_2peak were assessed at baseline and approximately 72h after the final training bout. Skeletal muscle biopsy samples were also obtained before and 72h after training and analysed for AS160 phosphorylation and COX II, COX IV, GLUT-4, Nur77 and SIRT1 protein expression.

Results: No changes in BMI, body composition, VO_2peak, glucose, insulin, NEFA and HOMA-IR were observed after training, either within or between groups. Skeletal muscle markers of glucose metabolism and mitochondrial function also remained unaltered after 2weeks of exercise training.

Conclusions: Our findings show that 2weeks of reduced-volume SIT or TER did not elicit any measurable metabolic adaptations in sedentary obese men. Further work is needed to determine the minimal amount of exercise required for short-term adaptations in this population.