Keeping the heart healthy in middle age may also help protect the brain decades later.
New research suggests that physical activity and healthy blood sugar levels during midlife are linked to a slower loss of memory and thinking skills as people grow older.
The study came from UT Health San Antonio, the academic health center of The University of Texas at San Antonio. It focused on adults from San Antonio and looked closely at whether heart-health factors were connected with changes in thinking ability over time.
The research was published on July 23 in Alzheimer’s & Dementia: Behavior & Socioeconomics of Aging. Its title is “Longitudinal association between midlife cardiovascular health and cognitive change in a bi-ethnic cohort.”
Dementia is becoming a growing health challenge as populations live longer. Alzheimer’s disease is the most common cause of dementia, and millions of Americans are already living with it.
Although age and genetics cannot be changed, researchers increasingly believe that some dementia risks can be reduced. High blood pressure, diabetes, smoking, lack of exercise, and other problems that harm the heart and blood vessels may also affect the brain.
The brain needs a steady supply of oxygen-rich blood to work properly. Over many years, damage to blood vessels can reduce this supply and may contribute to changes in memory, attention, and other thinking abilities.
For the new study, researchers analyzed 402 adults from San Antonio. Their average age was about 58, nearly 59% were women, and 52% were Hispanic, mainly Mexican American, while the remaining participants were non-Hispanic white.
This mix was especially valuable because Hispanic adults have often been underrepresented in Alzheimer’s research. At the same time, they face a higher burden of Alzheimer’s disease and several health conditions linked to dementia risk.
The researchers used information from two long-running projects, the San Antonio Heart Study and the San Antonio Longitudinal Study of Aging. The first examined diabetes and heart disease, while the second followed older adults to learn more about chronic illness, disability, and aging.
Heart health in midlife was measured using the American Heart Association’s Life’s Simple 7 approach. It considers physical activity, diet, smoking, blood pressure, body weight, cholesterol, and fasting blood sugar.
Fasting blood sugar measures the amount of glucose in the blood after a person has not eaten for several hours. Persistently high levels can be a sign of diabetes or poor blood sugar control, which can damage blood vessels throughout the body.
Participants’ thinking abilities were tested as many as four times using the Mini-Mental State Examination. This commonly used screening test checks skills such as memory, attention, orientation, and the ability to follow simple instructions.
The researchers found that the factors linked most strongly to slower cognitive decline were not exactly the same in the two ethnic groups. Among Mexican American participants, doing any physical activity rather than being inactive was especially strongly associated with slower decline.
Among non-Hispanic white participants, lower fasting blood glucose was linked to slower loss of thinking abilities. A fasting glucose level of 126 milligrams per deciliter or lower was associated with a better cognitive path over time.
Exercise could support the brain in several ways. Regular movement can improve blood flow, help control blood pressure and blood sugar, support sleep, and reduce the risk of conditions that damage blood vessels.
Good blood sugar control may also matter because diabetes can affect both large and small blood vessels. Over time, these changes may reduce brain health and increase the risk of stroke and cognitive problems.
The ethnic differences are interesting, but they should be interpreted carefully. The study included only 402 people, so the researchers said larger studies are needed to determine whether these differences are consistent in other populations.
The study also cannot prove that exercise or lower blood sugar directly caused slower cognitive decline. It was an observational study, meaning researchers identified relationships in existing health data rather than assigning people to different lifestyles and watching what happened.
Still, the long follow-up and the inclusion of Hispanic and non-Hispanic white adults from the same community are important strengths. Comparing people from a shared geographic setting may reduce some differences that can complicate studies involving populations from completely different regions.
The researchers also adjusted their analysis for factors including age, sex, education, and income. They performed additional checks to see whether people leaving the study over time could have unfairly changed the results.
Taken together, the findings support a growing idea in dementia research: protecting cardiovascular health in middle age may be one practical way to support the brain later. Exercise and good control of blood sugar already have well-established benefits for the heart, making their possible connection with healthier brain aging especially important.
However, the study does not show that one habit can prevent Alzheimer’s disease, and the different findings between ethnic groups need confirmation. Its strongest message is that dementia risk develops over many years and may be influenced by health long before memory problems begin.
Participants are now being invited into the San Antonio Heart and Mind Study, which will use modern brain imaging and other neurological measurements. That work may help scientists understand more clearly how midlife heart health becomes connected with changes inside the aging brain.
Source: UT Health San Antonio.
