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Non-invasive continuous monitoring of blood pressure and cardiac indexusing an isometric arm exercise protocol in young adults (Bachelor thesis)

Πύλιος, Ιωάννης-Πρόδρομος/ Pylios, Ioannis- Prodromos

Prolonged isometric (static) contraction causes constant intramuscular pressure and imposes a significant pressure load on the vascular system, promoting its function. The purpose of this research will be to monitor and compare the hemodynamic responses of a static exercise protocol, with a dumbbell, through isometric activation of the dominant upper limb in young adults. The sample consisted of a total of 20 students who were divided into the trained group (n= 10, age: 20.0 ± 1.6 yrs, height: 180 ± 9.6 cm and body weight: 87.9 ± 22.2 kg) and untrained (n= 10, age: 22.2 ± 2.5 yrs, height: 177.7 ± 6.9 cm and body weight: 77.5 ± 11.5 kg) young boys. The evaluation protocol of the examined variables included isometric activation (elbow flexion at 90 degrees) of the dominant upper extremity using external resistance with a constant weight dumbbell (3.6 kg). Body composition was further determined by multi-frequency segmental analysis (Tanita MC 780 MA). Non-invasive continuous monitoring (Finapres Nova) was used to monitor the hemodynamics of the sample during the isometric exercise protocol. Specifically, 3 sets x 2 min were performed, with a passive break of one minute (1min) between isometric efforts. Significant differences were observed in the mean values of changes, overall in each set, of blood pressure (BP), heart rate (HR, b/min), cardiac output (CO, l/min), total peripheral resistance (TPR, mmHg*s/ml) and the double product (RPP, mmHg*bpm). The analysis of variance showed that there was a statistically significant interaction between the groups (trained & untrained) and the performance of the 2-minute isometric efforts (group x sets), mainly, the variable heart rate [F(3,54)= 4.437, p= 0.007] and the double product [F(3,54)= 4.210, p= 0.009].Conclusively, statistically significant differences were observed between the two groups (exercise and non-exercise) in the first two hemodynamic parameters, heart rate and double product. In contrast, no statistically significant changes were observed in the hemodynamic parameters of cardiac output and total peripheral resistance. This can be attributed to the fact that, for the group of exercisers, the use of the specific weight dumbbell (3.6 kg) was not sufficient to induce notable hemodynamic changes.