Objectives: Measurement of the propagation times of cardiac-induced pulses along the arterial tree provides an important tool for studying arteries. The aim of our study was to measure the carotid-radial pulse transit time (c-rtT) in young healthy subjects before, during and 20 minutes after aerobic exercise and to compare it with the pulse arrival time to the capillary bed of the finger tip (PATc).

Methods: Following ethical approval eight men (20.8±0.4 years old) were recruited. We measured ECG, arterial blood pressure using Finapres Ohmeda, laser Doppler skin blood flow on the finger pulp and carotid or radial pulse with a tonometer (Millar SPT 30). After 5 minutes supine rest subjects mounted the cycloergometer and started a graded exercise until 85% of their maximal heart rate was reached. They recovered for 20 minutes. c-rtT and PATc were calculated.

Results: Our results revealed that c-rtT exhibited no statistically significant differences before and 20 minutes after exercise (111.3±4.1ms and 109.7±3.5ms), but was significantly decreased at highest workload (90.1±0,2ms). On the other hand PATc was increased 20 minutes after exercise compared to resting values (130.3±8.1ms and 120.7±5.5ms) and significantly decreased at highest workload (104.5±1.6ms). A linear correlation between c-rtT and corresponding RR interval duration during exercise was found (p<0.001) but no correlation between PATc and RR.

Conclusions: During exercise increased sympathetic tone could be the main reason for the decreased c-rtT, but other mechanisms should contribute to the regulation of the finger tip skin microcirculation, where termoregulation plays a major role.