The effect of age on cerebrovascular reactivity to cold pressor test and head‐up tilt

Objectives – To compare the cold pressor test (CPT) and head‐up tilt (HUT) responses of the older and younger healthy individuals by transcranial Doppler. Subjects and methods – Forty healthy volunteers were divided into two age groups (18–39 years, 40–69 years). Mean blood velocity ( v m ) in both middle cerebral arteries was monitored during CPT and HUT. Mean arterial blood pressure, heart rate and end‐tidal CO 2 (Et‐CO 2 ) were measured simultaneously. Results – The v m increased by 7.1% during CPT and decreased by 10.1% during HUT. The v m responses were significantly lower in the older group ( P  < 0.01). Linear regression analysis showed a significant effect of age on d v m during both CPT ( P  < 0.01) as well as HUT ( P  < 0.01). Conclusion – The age affected the v m responses to CPT and HUT in the group of older subjects.