Hypertension is often called the “silent killer” because it can quietly damage the body for years without causing obvious symptoms. When it goes untreated, high blood pressure can also affect how the brain works. In some people, this can look a lot like dementia, with problems in memory, thinking, and daily functioning.
How high blood pressure affects the brain
Blood pressure is the force of blood pushing against the walls of your arteries. When it stays too high over time, it can damage blood vessels all through the body, including the tiny ones that feed the brain. This long term injury to brain blood vessels is known as cerebrovascular disease and is a major cause of what doctors call vascular cognitive impairment, a spectrum that includes vascular dementia and milder thinking problems linked to blood flow issues in the brain. https://www.medlink.com/articles/vascular-cognitive-impairment
Studies have shown that uncontrolled hypertension is one of the most common risk factors for vascular dementia, and people with high blood pressure have a much higher risk of late life cognitive decline in general. Some research suggests they may have around five times the risk of significant cognitive decline later in life and roughly double the risk of developing dementia compared with people whose blood pressure is normal. https://www.aol.com/articles/study-just-uncovered-more-warning-174700492.html Over many years, this ongoing stress on the brain’s vessels can lead to small strokes, tiny areas of brain tissue damage, and changes in the brain’s white matter. All of these can gradually weaken thinking and memory.
Cognitive symptoms of untreated hypertension that resemble dementia
Untreated or poorly controlled high blood pressure can cause symptoms that are easy to confuse with early dementia, especially in older adults. Some of the overlapping signs include:
1. Mental fog and slower thinking
Doctors and patients often describe a sense of “mental fog” when blood pressure is too high. Reduced blood flow and oxygen to the brain can make thinking feel slower and less sharp. People may have trouble staying focused, following conversations, or switching between tasks. A medical clinic article notes that chronic high blood pressure can impair blood flow to the brain, leading to mental fog, confusion, and reduced ability to concentrate. https://www.primamedicine.com/blog/dont-ignore-the-silent-killer-8-subtle-signs-your-blood-pressure-might-be-dangerously-high-in-northern-virginia/ In daily life, this can look like the early executive function problems seen in vascular cognitive impairment, such as trouble organizing tasks or planning ahead. https://www.medlink.com/articles/vascular-cognitive-impairment
2. Forgetfulness and confusion
People with very high or long standing high blood pressure may notice more frequent episodes of forgetfulness, such as misplacing items, repeating questions, or losing track of what they were doing. Some describe episodes of confusion, where they feel temporarily disoriented or have difficulty making sense of simple situations. Health information aimed at patients notes that untreated hypertension can cause forgetfulness or confusion when brain blood flow is compromised. https://www.primamedicine.com/blog/dont-ignore-the-silent-killer-8-subtle-signs-your-blood-pressure-might-be-dangerously-high-in-northern-virginia/
These symptoms can easily be mistaken for early Alzheimer type dementia, especially if family members see their loved one becoming more forgetful over months or years. However, in vascular problems tied to hypertension, memory loss may be somewhat less prominent than issues with attention, planning, or speed of thinking, at least in the early stages. https://www.medlink.com/articles/vascular-cognitive-impairment
3. Difficulty with everyday tasks
As vascular cognitive impairment progresses, people can have problems managing finances, medications, or complex household tasks, even if their memory for past events seems relatively intact. This pattern is common in cognitive disorders driven by blood vessel disease. https://www.medlink.com/articles/vascular-cognitive-impairment From the outside, however, these changes can look just like dementia, because the person is clearly less able to function independently and may make poor decisions.
4. Fatigue, low motivation, and slower responses
High blood pressure can cause generalized fatigue and low energy. When someone is chronically tired, they may seem apathetic, slow to respond, or less engaged with others. A primary care source notes that sustained high blood pressure can cause unusual fatigue and mental fog, both of which can make a person appear cognitively impaired. https://www.primamedicine.com/blog/dont-ignore-the-silent-killer-8-subtle-signs-your-blood-pressure-might-be-dangerously-high-in-northern-virginia/ In older adults, this can sometimes be misinterpreted as “slipping into dementia” when it is partly a result of vascular strain and decreased brain perfusion.
5. Stroke related changes
Untreated hypertension is the leading cause of both major strokes and “silent” strokes, which are very small areas of brain damage that may not cause obvious symptoms at the time they occur. Over years, however, the accumulation of these small injuries can lead to noticeable cognitive decline. Clinical reviews of vascular cognitive impairment explain that repeated small strokes and white matter damage, often driven by long standing hypertension, are key drivers of this kind of dementia. https://www.medlink.com/articles/vascular-cognitive-impairment
