The American College of Sports Medicine has recently published a review of principles for prescribing exercise programs that support brain health in aging (Exercise, Sport and Movement, Winter 2024;2(1):1-5). The authors report that the loss of memory occurs with atrophy of the hippocampus, a key brain region involved in learning and memory, and that in people with Alzheimer’s disease, the rate of hippocampal atrophy is 2.5 times faster than in healthy aging. They also note that physical inactivity has been identified as the greatest modifiable risk factor for dementia prevention, and that lack of exercise can contribute to dementia risk as much as genetics.
In one study, almost 50,000 non-demented people in the UK, age 60 and older, wore wrist accelerometers 24 hours a day for a week to measure their levels of activity (JAMA, Sept 12, 2023;330(10):934-940), and were then followed for almost seven years. By the end of the follow-up period, 414 of the participants had been diagnosed with dementia.  Compared to sitting for a little over nine hours a day, those who spent 10 hours a day sitting or lying had an eight percent increased risk for becoming demented and those who spent 12 or more hours not moving had a 63 percent increased risk for becoming demented. Those who spent 15 hours of sitting/day were three times more likely to have become demented.
Maintaining a Healthful Weight
Moving around helps people reach and maintain a healthful weight. Researchers followed more than 1,600 adults in their 70s for 10 years and found that increasing body fat was associated with considerable loss of memory and reasoning (J Am Geriatr Soc, 2023 Sep;71(9):2759-2768). Excess body fat prevents the body from responding to insulin, which increases risk factors for heart attacks, diabetes, high cholesterol and high blood pressure. Other studies have shown that larger muscles, greater strength and increased coordination are all associated with reduced dementia risk (JAMA Netw Open, 2022 Jun; 5(6):e2218314).
Risk Factors for Dementia are the Same as for Heart Attacks
Dementia has the same risk factors as heart attacks (Dementia, Aug, 2021;2(8):e498-e506), and reducing and keeping cholesterol and triglycerides low is a likely way to reduce dementia risk. Several previous studies have shown that variability in the bad LDL and good HDL cholesterol and triglycerides increased risk for heart attacks independent of levels and cholesterol-lowering treatment (J Clin Lipidol, 2018;12(2):356-366). Anything that can damage blood vessels to increase heart attack risk can also damage the brain, such as:
• High blood pressure
• High cholesterol
• Obesity
• Lack of physical activity
• An unhealthful diet
• Not eating a lot of fiber-rich plants
• Alcohol
• Diabetes that is not well controlled
• Smoking
My Recommendations
One key to helping to prevent dementia is to keep on moving. You do not have to have a specific exercise program, you just need to keep moving for a large part of each day. It is harmful just to sit or lie down all day long. It is healthful to mow your lawn, wash your dishes, make your bed, vacuum your house, go for a walk, and participate with your friends in activities in which you are moving your arms and legs — dancing, cycling, swimming, running, nature walks and so forth.
Aging is the major risk factor for dementia that none of us can change. However, you can work on those risk factors that can be improved with lifestyle changes. If you are concerned about your own memory status, your doctor may recommend a referral to a dementia specialist. At a minimum, the screening tests they will do can provide a base line to help you monitor any progression.
