“…In an effort to overcome the first barrier, BP interventions have been implemented to increase the range of BPs upon which estimation models are trained. Many different interventions have been used, such as mental arithmetic 8 – 10 , cold pressor test 9 – 11 , nitroglycerin 9 , low-intensity exercise 12 , 13 , static handgrip exercise 7 , 14 , 15 , Valsalva maneuver 7 , 14 , 15 and slow breathing 9 , 10 . However, it is difficult to know how the BP changes imposed by the interventions reflect natural changes in BP during daily life.…”