The Variability of Blood Pressure

Studies such as those recently made by Alvarez,1and Diehl and Sutherland,2in which a surprisingly large number of presumably young adults are reported with elevation of blood pressure, lead one to wonder what proportion of these high readings can be attributed to fluctuations or variations of the blood pressure. Unquestionably many of the persons who show high pressures during required examinations of a group usually give readings; in fact, by taking repeated readings of the blood pressure of those university students who, on entrance examinations, had systolic pressures of 140 mm. or more, Diehl and Sutherland2found that the pressures of only 15 per cent of this group persisted at that high level. Other students showed high readings on some occasions and low readings on others, while the largest proportion were above normal on only the initial reading. In all groups, however, there were sufficient variations