title: Low-volume high-intensity interval training reduces hyperglycemia and increases muscle mitochondrial capacity in patients with type 2 diabetes.
abstract: Low-volume high-intensity interval training (HIT) is emerging as a time-efficient exercise strategy for improving health and fitness. This form of exercise has not been tested in type 2 diabetes and thus we examined the effects of low-volume HIT on glucose regulation and skeletal muscle metabolic capacity in patients with type 2 diabetes. Eight patients with type 2 diabetes (63 ± 8 yr, body mass index 32 ± 6 kg/m(2), Hb(A1C) 6.9 ± 0.7%) volunteered to participate in this study. Participants performed six sessions of HIT (10 × 60-s cycling bouts eliciting ∼90% maximal heart rate, interspersed with 60 s rest) over 2 wk. Before training and from ∼48 to 72 h after the last training bout, glucose regulation was assessed using 24-h continuous glucose monitoring under standardized dietary conditions. Markers of skeletal muscle metabolic capacity were measured in biopsy samples (vastus lateralis) before and after (72 h) training. Average 24-h blood glucose concentration was reduced after training (7.6 ± 1.0 vs. 6.6 ± 0.7 mmol/l) as was the sum of the 3-h postprandial areas under the glucose curve for breakfast, lunch, and dinner (both P < 0.05). Training increased muscle mitochondrial capacity as evidenced by higher citrate synthase maximal activity (∼20%) and protein content of Complex II 70 kDa subunit (∼37%), Complex III Core 2 protein (∼51%), and Complex IV subunit IV (∼68%, all P < 0.05). Mitofusin 2 (∼71%) and GLUT4 (∼369%) protein content were also higher after training (both P < 0.05). Our findings indicate that low-volume HIT can rapidly improve glucose control and induce adaptations in skeletal muscle that are linked to improved metabolic health in patients with type 2 diabetes.
authors.affiliation: Dept. of Kinesiology, McMaster University, Hamilton, Canada.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Little
authors.forename: Jenna B
authors.initials: JB
authors.lastname: Gillen
authors.forename: Michael E
authors.initials: ME
authors.lastname: Percival
authors.forename: Adeel
authors.initials: A
authors.lastname: Safdar
authors.forename: Mark A
authors.initials: MA
authors.lastname: Tarnopolsky
authors.forename: Zubin
authors.initials: Z
authors.lastname: Punthakee
authors.forename: Mary E
authors.initials: ME
authors.lastname: Jung
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Gibala
mesh_terms: D000222:Adaptation, Physiological; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000378:metabolism / Q000628:therapy*; D005081:Exercise Therapy / Q000379:methods*; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D006801:Humans; D006943:Hyperglycemia / Q000097:blood / Q000628:therapy; D008875:Middle Aged; D008931:Mitochondria, Muscle / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D010809:Physical Fitness; D010865:Pilot Projects
chemical_list: D001786:Blood Glucose; D051275:Glucose Transporter Type 4; C495692:SLC2A4 protein, human