As autonomic nervous system dysregulation and, specifically, heart rate variability (HRV) are implicated in the pathophysiology of obesity [26 (link)], we measured HRV using a pulse transducer (TN1012/ST; ADInstruments, Sydney, Australia) that attached to the participant's thumb and connected to a PowerLab 2/26 acquisition device (ML826; ADInstruments).
Baseline eye blink rate (EBR) positively correlates with central dopamine function [27 (link)], which has been shown to vary with BMI and which is suggested to play a role in the association between BMI and cognitive function [28 (link)]. Therefore, concurrently with the HRV measurement, a 5‐minute video of participants' faces was recorded using a webcam while they were instructed to let their mind wander but to not fall asleep. The total number of blinks for each participant was averaged over the recording period to produce EBR in blinks per minute.
Baseline eye blink rate (EBR) positively correlates with central dopamine function [27 (link)], which has been shown to vary with BMI and which is suggested to play a role in the association between BMI and cognitive function [28 (link)]. Therefore, concurrently with the HRV measurement, a 5‐minute video of participants' faces was recorded using a webcam while they were instructed to let their mind wander but to not fall asleep. The total number of blinks for each participant was averaged over the recording period to produce EBR in blinks per minute.