Brown adipose tissue (BAT) activity is induced when humans are exposed to cold. Therefore, cold exposure prior to the F-18-FDG-PET/CT scan is used as a tool to quantify BAT. Several cooling protocols, including fixed and personalized ones are currently in use. The aim of the present study was to determine the effect of a new personalized cooling protocol where the shivering threshold was measured on a separate day, on BAT volume and activity in young adults. A total of 47 adults (n = 28 women) aged 22 +/- 2 years participated in the study. We determined participants’ shivering threshold (visually and self-reported) using a water perfused cooling vest in an air-conditioned cold room. 48-72 h later, participants wore the cooling vest set at similar to 4 degrees C above the shivering threshold for 60 min prior to injection of F-18-FDG and similar to 5 degrees C above the shivering threshold for similar to 60 min after injection, until PET/CT scan. We quantified BAT following BARCIST 1.0 recommendations. We identified 40 participants (85%, n = 25 women) as PET+ and 7 (n = 3 women) as PET-. The PET+ group presented significantly higher BAT volume and activity than PET-group (all P < 0.05). PET+ women had higher BAT mean activity than PET+ men (SUVmean: 5.0 +/- 1.6 vs. 3.6 +/- 0.9 g/ml respectively, P = 0.003), and there were no significant sex differences in BAT volume (P = 0.161). A total of 9 out of 47 participants did not shiver during the shivering threshold test. Our findings are similar to previous cold-stimulated human BAT studies; therefore, we conclude that our personalized cooling protocol is able to activate BAT in young adults.