Having a “senior moment?” That may have more to do with high blood pressure than an aging brain, according to new research.

Researchers at North Carolina State University have found that spikes in blood pressure are directly linked to diminished cognitive function among the elderly. This correlation holds especially true for those seniors with already high blood pressure, their report suggests. Study subjects with an average systolic blood pressure of 130 or higher experienced a significant decrease in cognitive function when faced with a sudden spike in blood pressure.

Typically, such spikes occur during stressful moments, report authors say. This suggests that some seniors may find it hard to think rationally or logically during stressful situations. Report authors note that seniors with normal or lower blood pressure do not experience the same diminished cognitive functions under stress. The full study appears in the current issue of the Journal of Gerontology: Psychological Sciences.