Reduced Cardiac Output and Cognition
The heart pumps blood to deliver oxygen and nutrients throughout the body, including the brain. When cardiac output drops, the heart does not pump enough blood. This reduced flow can harm brain function and lead to problems with thinking and memory.
Cardiac output is the amount of blood the heart sends out each minute. It depends on heart rate and how much blood fills the heart between beats. Conditions like coronary artery disease or heart failure lower cardiac output. These issues are common in older adults and create a link between heart health and brain health.
People with coronary artery disease often face faster cognitive decline. Their brains may shrink in key areas, such as the hippocampus, which handles memory. Lower cardiorespiratory fitness, a sign of poor cardiac output, ties to smaller brain volumes and an older-looking brain structure. Patients with stable coronary artery disease who have better fitness show larger hippocampal volumes and less brain loss compared to those with low fitness.
In older patients with cardiovascular disease, reduced phase angle from bioelectrical tests signals higher risk of cognitive impairment. Phase angle measures cell health and reflects issues like inflammation and oxidative stress. These factors overlap with brain diseases and form a cycle where heart problems worsen thinking skills. Early detection of low phase angle could help spot at-risk patients for simple screening.
Metabolic issues tied to low cardiac output, like insulin resistance measured by METS-IR, also hurt cognition. Higher METS-IR links to poorer memory, verbal fluency, processing speed, and overall thinking ability. This effect grows stronger past a threshold of 27.78, where brain stress from poor blood sugar, fats, and obesity speeds decline. The link holds across ages, genders, and races.
Even in younger people, low cardiovascular fitness predicts weaker cognition. At age 18, fitter individuals score higher on intelligence tests for logic, verbal skills, and spatial tasks. Gains in fitness from ages 15 to 18 boost these scores, likely through better brain blood flow and growth factors that aid brain plasticity.
Heart-brain ties go both ways. Cognitive issues make heart disease worse by lowering treatment follow-through. Tools like fitness tests, phase angle, and metabolic scores offer ways to track and perhaps prevent decline. Submaximal fitness measures work for those unable to push to full effort, making checks easier.
Sources
https://academic.oup.com/eurjpc/advance-article/doi/10.1093/eurjpc/zwaf765/8380283
https://pmc.ncbi.nlm.nih.gov/articles/PMC12703100/
https://pmc.ncbi.nlm.nih.gov/articles/PMC12750669/
https://www.pnas.org/doi/10.1073/pnas.0905307106
https://www.ahajournals.org/doi/full/10.1161/JAHA.125.044438
https://journals.sagepub.com/doi/10.1177/13872877251409343
