Table 2.
Effect of Mental Stress on Carotid Artery Vascular Responses in Young vs Older Normal Subjects
| Young Normal (n = 10) | Older Normal (n = 20) | |||
| Variable | Baseline | Peak | Baseline | Peak |
| Systolic BP (mm Hg) | 110 ± 7 | 124 ± 8* | 118 ± 12 | 131 ± 22* |
| Diastolic BP (mm Hg) | 69 ± 7 | 82 ± 6* | 73 ± 10 | 79 ± 11* |
| Mean BP (mm Hg) | 83 ± 6 | 96 ± 7* | 88 ± 9 | 96 ± 11* |
| Heart Rate (bpm) | 71 ± 10 | 87 ± 13* | 69 ± 12 | 80 ± 17* |
| CA diameter (cm) | 0.61 ± 0.06† | 0.65 ± 0.07* | 0.63 ± 0.06† | 0.66 ± 0.07* |
| PSV (cm/s) | 110 ± 23 | 119 ± 28 | 72 ± 16 | 76 ± 13 |
| EDV (cm/s) | 23 ± 4 | 25 ± 6 | 19 ± 6 | 21 ± 5* |
| TAM (cm) | 22 ± 7 | 25 ± 6 | 18 ± 5 | 23 ± 6*† |
| RI | 0.84 ± 0.1 | 0.79 ± 0.1* | 0.73 ± 0.1 | 0.72 ± 0.1 |
| PI | 2.4 ± 0.7 | 2.1 ± 0.4 | 1.7 ± 0.6 | 1.5 ± 0.4 |
| Flow (ml/min) | 419 ± 134 | 541 ± 209* | 351 ± 114 | 454 ± 136*† |
Values are mean ± SD. Numbers in brackets represent number of participating subjects in each group. Data represents the effects of the mental stress task that produced the maximum increase in blood flow in both groups. *p < 0.05 vs. baseline. †p < 0.05 vs. hypertensive. BP, blood pressure; PSV, peak systolic velocity; EDV, end-diastolic velocity; TAM, time average mean velocity; TAM, time averaged mean velocity. Flow = 3.14× 60× (radius)2× TAM; RI, resistive index; PI, pulsatility index.