Feeling dizzy after standing due to a sudden drop in blood pressure can be a minor problem due to medication use or dehydration. But when it happens often, it can be a sign of a more serious condition called orthostatic hypotension, which is defined as a drop in blood pressure within three minutes of sitting or standing.
"Our study looked at delayed orthostatic hypotension, when the drop in blood pressure happens more than three minutes after standing or sitting up," said study author Christopher Gibbons from Harvard Medical School in Boston.
"Our findings suggest that more than half of people with the delayed form of this condition will go on to develop the more serious form of this disease," Gibbons noted.
For the study, researchers reviewed the medical records of 165 people with an average age of 59 who completed nervous system testing and were followed for 10 years.
Of those, 48 were diagnosed with delayed orthostatic hypotension, 42 had orthostatic hypotension and 75 did not have either condition.
The study found that over 10 years, 54 percent of participants with delayed orthostatic hypotension progressed to orthostatic hypotension and 31 percent developed a degenerative brain disease such as Parkinson's or dementia with Lewy bodies.
The death rate over 10 years for those with the delayed condition who progressed to orthostatic hypotension was 50 percent.
The findings appeared in the online issue of the journal Neurology