We already know quite a lot about how brachial blood pressure (BP) varies by day and time—might chronology also influence arterial occlusion pressure? To their knowledge, say researchers from the University of Mississippi and National Institute of Fitness and Sports in Kanoya, Japan, no study has examined that. They hypothesized that arterial occlusion measurements would oscillate in a pattern that mimicked diurnal variation in brachial systolic blood pressure (bSBP)—specifically, that the measurements would be higher in the evening than in the morning.
In their study of 22 participants, the researchers conducted 4 testing sessions, at 8 am and 6 pm, 48 hours apart. They measured arm circumference, bSBP, and bSBP at rest. They measured arterial occlusion pressure using a cuff inflated on the proximal portion of the upper arm, with a Doppler probe placed over the radial artery.
Pressure varied not only between days but within a day. They found significant difference between morning on day 1 and all other visits, although they say that may have been due to anxiousness during the first visit. But they also found a time effect for morning day 2 compared with all other visits. On day 1 there were no differences from morning to evening; on day 2, occlusion pressure increased from morning to evening.
“The interrelationship between the oscillating nature of different variables is extremely difficult to study,” the researchers say, “and makes it hard to ascertain the rhythm of one physiological variable in the absence of others, due to the inability to isolate variables from temporal progression.” To get the most accurate readings, they advise taking multiple measurements.