Most people have felt dizzy after standing up too quickly. But what if that same change in posture could also affect how well someone thinks, remembers information or makes decisions? A new study by Faculty of Health doctoral student Olivia Ramraj looks for the answer.
For Ramraj, the path to exploring that question began during her master's research, which considered the relationship between vascular function and cognition in people with Type 2 diabetes.
As she and her supervisor, Heather Edgell, a professor in the Department of Kinesiology & Health Science, began planning her PhD projects, they wanted to understand how cardiac output and blood flow to the brain might contribute to cognitive function in this population. "We were interested in using upright posture as a stressor on the heart and vascular system that could potentially affect cognition by decreasing brain blood supply," she says.
But, when they searched for research exploring posture and thinking in people with Type 2 diabetes, they found very little. That gap led Ramraj and her team to conduct a systematic review examining what researchers already knew about the relationship in other health conditions.
"Our overarching goal was to determine whether posture affects cognition and to develop studies that could help uncover the driving mechanism," she says.
The question is an important one. Orthostatic hypotension, a condition that causes blood pressure to drop when a person stands, is common among older adults and people with conditions such as Parkinson's disease and Type 2 diabetes. Previous research has also linked the condition to cognitive impairment, decline and dementia. Yet, assessments are typically conducted while people are seated or at rest, although symptoms occur when people are standing.
Ramraj and her colleagues analyzed existing research on posture and cognition in people with orthostatic hypotension. They also looked at studies that compared performance in lying and upright positions to learn whether posture could influence how people think and process information.
Their findings suggest it can.
Across the research, a consistent pattern emerged: people with orthostatic hypotension generally performed worse on tests when upright versus when lying down. The most consistent findings involved executive function, the mental processes that help people plan, solve problems, focus attention and adapt to changing situations. Every study that examined executive function found poorer performance when participants were standing.
The conclusions raise questions about how cognitive function is evaluated. If difficulties become more apparent while people are upright, seated assessments may not fully reflect how individuals function in everyday life. The authors suggest testing in multiple postures could help improve the accuracy of evaluations and identify impairments that might otherwise be missed.
For Ramraj, the results were particularly notable because people spend much of their daily lives upright and the cognitive abilities most affected by posture are among the most important. "This could potentially affect daily functions that allow us to remain independent, for instance the ability to plan, make decisions, learn and retain information," she says.
The findings also point to opportunities for future research and changes in how mental function is evaluated. Ramraj hopes her work encourages researchers and clinicians to consider evaluating thinking abilities in multiple postures.
"It is important that our cognitive assessments are comparable to real-life settings and experiences where people are expected to perform tasks while lying down, seated, standing and sometimes while walking," she says.
She also sees a need for better ways to evaluate cognitive function and brain blood flow simultaneously. Currently, the two are often studied separately, making it difficult to fully understand how physiological changes may influence performance.
Ramraj plans to build on her research by returning to the question that sparked the project: whether changes in cardiac output and brain blood flow contribute to cognitive impairment in people with Type 2 diabetes. She hopes the evidence encourages other researchers to explore similar questions in other populations.
This project, she says, underscores how much there is still to learn about the body's response to daily life, even activities that seem routine.
"It never fails to amaze me that our bodies respond to everyday activities such as standing upright, that sometimes we take for granted," says Ramraj.