| Abstract: | The relationships between arterial systolic and diastolic blood pressure (SBP and DBP), interbeat interval (IBI), and various pulse transit times were investigated in 5 young, healthy males during physical exercise and at rest. Transit times monitored were radial, brachial and dorsalis pedis RPIs (ECG R-wave to pulse intervals), and brachial-radial and radial-dorsalis pedis PPIs (pulse to pulse intervals). Experimental sessions consisted of three periods: two involving mild dynamic exercise plus rests, and one involving static exercise (handgrips) plus rests. Correlation and regression analyses within period and subject were performed on individual beat data. Radial RPI was highly correlated with SBP (during dynamic periods, range ?.57 to ?.89, median r?.81; during static periods, range ?.80 to ?.88, median r=?.87) and moderately correlated with DBP (during dynamic periods, range ?.10 to ?.63, median r?.52; during static periods, range ?.17 to ?.77, median r?.66). Median correlations of radial RPI with SBP and DBP during exercise and rest separately were ?.75 and ?.40 (dynamic), ?.79 and ?.57 (static), and ?.74 and ?.26 (rest). The IBI X radial RPI product was very highly correlated with the rate-pressure product (heart rate X SBP), an index of myocardial oxygen consumption (median r=?.96). The only PPI which reliably indexed SBP or DBP change was brachial-radial PPI during the static exercise period (median r=?.86 and ?.83). |
