“…In particular, attempts to find meaningful information from PPG using various deep learning models are continuously increasing. Representative applications of PPG analysis using deep learning include heart rate estimation ( Biswas et al, 2019 ; Reiss et al, 2019 ; Panwar et al, 2020 ; Chang et al, 2021 ; Mehrgardt et al, 2021 ), cuff-less blood pressure estimation ( Panwar et al, 2020 ; El-Hajj and Kyriacou, 2021a , b ; Schrumpf et al, 2021a , b ; Tazarv and Levorato, 2021 ), and arterial fibrillation prediction ( Poh et al, 2018 ; Kwon et al, 2019 ; Aschbacher et al, 2020 ; Cheng et al, 2020 ; Pereira et al, 2020 ). In addition, PPG-based deep learning models are being used for respiratory rate estimation ( Ravichandran et al, 2019 ), sleep monitoring ( Korkalainen et al, 2020 ), diabetes ( Avram et al, 2019 ), vascular aging estimation ( Dall’Olio et al, 2020 ), and peripheral arterial disease classification ( Allen et al, 2021 ).…”