ABSTRACT
Exaggerated blood pressure (BP) response to mental stress has been known to be a prognostic factor for cardiovascular disease. It has been argued that such unusual vascular reactivity to mental stress may arise from insulin resistance. To examine the vascular responses to mental stress, we evaluated the stress-related changes in BP and the augmentation index (AI), an index of arterial stiffness, in normotensive young males. Changes in late systolic BP (SBP2) representing central aortic pressure were also examined. Subjects were 86 males (21+/-2 years), 13 of whom were classified as obese (>or=25 kg/m(2)). AI was obtained from the radial arterial waveform as a ratio of the height of the late systolic peak to that of the first peak. Blood pressure and AI measurements were taken before, during and after a simple mental arithmetic test (MAT) lasting 3 min. Systolic BP (baseline 125+/-13, during MAT 133+/-13, post-MAT 124+/-11 mmHg; p<0.001) and heart rate (74+/-12, 81+/-13, 74+/-11 beats/min; p<0.001) were significantly increased during the MAT, whereas AI showed a slight reduction. In a separate analysis, the opposite response was observed between obese subjects showing increased AI (54+/-11, 56+/-13, 52+/-11%) and non-obese subjects who showed reduced AI (54+/-12, 51+/-12, 53+/-12%; p=0.032). The responses in SBP and SBP2 (obese 103+/-14, 117+/-12, 104+/-12; non-obese 98+/-13, 104+/-12, 97+/-12 mmHg; p=0.007) were also larger in the obese subjects. Stress-related transient increases in arterial stiffness may be involved in the exaggerated responses in aortic pressure in obese subjects.
