According to a study by mahoney and others, a lower level of attention in older adults was linked to low blood pressure, which likely is related to reduced blood flow to the brain's frontal lobes.

According  to  a study  by  Mohoney and   others, a  lower  level  of   executive   attention  in  order  adults was  linked  to  low  blood  pressure,which   likely is  related  to  reduce blood  flow  to  the   brains frontal  lobes .Executive  attention  in  blocking potentially  which distract information  from  the   focus  of  attention.

Gay-lussac's law i think.