High-intensity interval training combining rowing and cycling efficiently improves insulin sensitivity, body composition and VO₂max in men with obesity and type 2 diabetes

AbstractAimNon-weight-bearing high-intensity interval training (HIIT) involving several muscle groups may efficiently improve metabolic health in obesity and type 2 diabetes. In a non-randomized intervention study, we examined the effect of a HIIT-protocol, recruiting both lower and upper body muscles, on insulin sensitivity, measures of metabolic health and adherence in obesity and type 2 diabetes.MethodsIn 15 obese men with type 2 diabetes and age-matched obese (n=15) and lean (n=18) glucose-tolerant men, the effects of 8-weeks supervised HIIT combining rowing and cycling were examined by DXA-scan, exercise test and hyperinsulinemic-euglycemic clamp.ResultsAt baseline, insulin-stimulated glucose disposal rate (GDR) was ∼40% reduced in the diabetic vs the non-diabetic groups (allp<0.01). In response to HIIT, insulin-stimulated GDR increased ∼30-40% in all groups (allp<0.01) explained by increased glucose storage. These changes were accompanied by ∼8-15% increases in VO2max, (allp<0.01), decreased fat mass and increased lean body mass in all groups (allp<0.05). There were no correlations between these training adaptations and no group-differences in these responses. HbA1c showed a clinically relevant decrease in men with type 2 diabetes (4±2 mmol/mol;p<0.05). Importantly, adherence was high (>95%) and no injuries were reported.ConclusionsA novel HIIT-protocol recruiting lower and upper body muscles efficiently improves insulin sensitivity, VO2max and body composition with intact responses in men with obesity and type 2 diabetes. The high adherence and lack of injuries show that non-weight-bearing HIIT involving several muscle groups is a promising mode of exercise training in obesity and type 2 diabetes.