Decreased insulin-stimulated brown adipose tissue glucose uptake after short-term exercise training in healthy middle-aged men

Aims: To test the hypothesis that high‐intensity interval training (HIIT) and moderate‐intensity continuous training (MICT) improve brown adipose tissue (BAT) insulin sensitivity. Participants and methods: Healthy middle‐aged men (n = 18, age 47 years [95% confidence interval {CI} 49, 43], body mass index 25.3 kg/m2 [95% CI 24.1‐26.3], peak oxygen uptake (VO2peak) 34.8 mL/kg/min [95% CI 32.1, 37.4] ) were recruited and randomized into six HIIT or MICT sessions within 2 weeks. Insulin‐stimulated glucose uptake was measured using 2‐[18F]flouro‐2‐deoxy‐D‐glucose positron‐emission tomography in BAT, skeletal muscle, and abdominal and femoral subcutaneous and visceral white adipose tissue (WAT) depots before and after the training interventions. Results: Training improved VO2peak (P = .0005), insulin‐stimulated glucose uptake into the quadriceps femoris muscle (P = .0009) and femoral subcutaneous WAT (P = .02) but not into BAT, with no difference between the training modes. Using pre‐intervention BAT glucose uptake, we next stratified subjects into high BAT (>2.9 µmol/100 g/min; n = 6) or low BAT (