A new study from University College London (UCL), published in the European Heart Journal, has found that signs of heart damage during middle age could raise your risk of dementia later in life. The big takeaway: even silent, hard-to-detect heart problems in your 40s, 50s, or 60s might slowly harm your brain and memory as you age.

What the study looked at

Researchers followed nearly 6,000 men and women in the UK, all civil servants, for 25 years as part of the long-running Whitehall II study, The Independent reported. None had dementia or heart disease when they started, and all were tested for troponin, a protein that’s released in the blood when heart muscle is hurt. Troponin is usually checked if someone might be having a heart attack, but this research used special “high-sensitivity” tests that pick up even tiny amounts—those that don’t cause symptoms but may signal slow, ongoing damage to the heart.

Key findings: Higher Troponin, higher dementia risk

The study’s main discovery was that people with higher troponin levels in middle age were much more likely to develop dementia decades down the line. Compared to those with the lowest troponin levels, the group at the top had a 38% higher chance of being diagnosed with dementia over the study period.What’s particularly important is that these higher troponin levels showed up in blood tests taken seven to twenty-five years before anyone showed symptoms of dementia. In other words, the warning signs of future dementia often appear long before forgetfulness or confusion starts.

How heart health connects to brain health

You might wonder, why does a heart protein matter for your brain? Here’s the link: troponin is a marker for heart muscle damage, which usually means your heart isn’t working quite right. A weaker heart can lead to reduced blood flow and less oxygen reaching the brain, gradually damaging brain cells and memory centers over time. Heart problems can also affect your blood vessels more generally, fueling conditions like high blood pressure and stroke, which are well-known dementia risk factors.Control shared risk factors—such as high cholesterol, high blood pressure, physical inactivity, and being overweight—and you may lower your chances of both heart disease AND dementia, say the researchers.

Changes in thinking and brain size

The study also did cognitive tests and looked at MRI scans of some participants’ brains. People with high troponin in middle age not only experienced a faster decline in memory and thinking (“cognition”), but by age 80 or 90 their mental abilities were equivalent to people who were one to two years older. On the MRIs, they had smaller hippocampus (the part needed for memory) and less “grey matter” (important for reasoning and processing information) – the kind of changes seen with aging and dementia.

Why midlife matters

Interestingly, the link between higher troponin and dementia was strongest when blood was tested in middle age, not later in life. This suggests midlife may be a particularly important window for catching and addressing heart health issues before they start affecting the brain.

What can you do?

The advice from experts is simple: keep your heart healthy to protect your brain. That means keep your blood pressure down, choose foods that help manage cholesterol, stay active, avoid smoking, and try to maintain a healthy weight. Everything you do for your heart, you’re also doing for your long-term memory.Silent heart damage now can lead to memory and thinking problems decades later. It’s worth paying attention to your heart health even if you feel fine—because that can help your brain age well, too. Little changes in daily habits may add up over the years, lowering your risk for both heart and brain troubles as you get older.