Increased cardiovascular reactivity to the cold pressor test is not associated with increased reactivity to isometric handgrip exercise

Individuals who respond with a rise of 15 mmHg or more in their systolic and/or diastolic blood pressure to a cold pressor test are called blood pressure hyperreactors. We examined whether hyperreactors (n = 8) showed greater reactivity of arterial stiffness, i.e., pulse wave velocity (PWV) and augmentation index normalized to a heart rate of 75 bpm (AIx@75), to the cold pressor test than normal reactors (n = 15), and whether the former showed larger cardiovascular responses to isometric handgrip exercise. The cold pressor test was performed following Hines-Brown's method, with subjects immersing their right hand in 4A degrees C water for 2 min. Isometric handgrip exercise was performed at 30% maximal voluntary contraction for 2 min. Comparison between hyperreactors and normal reactors by two-way ANOVA during cold pressor test revealed a group x time interaction for PWV and AIx@75 with a greater increase in hyperreactors. During isometric handgrip exercise, no group x time interactions were detected for all measurements. Blood pressure hyperreactors show larger cardiovascular responses to the cold pressor test, but not to isometric handgrip exercise in comparison to normal blood pressure reactors.