The 4 Need-to-Know Metrics for Brain Health

The 4 Need-to-Know Metrics for Brain Health

Keeping these numbers in check now can help keep your mind young for decades to come.

By Richard Isaacson, MDUpdated July 5, 2022


When you’re in your 20s or 30s, the words “preventive neurology” don’t usually catch your attention. After all, your memory seems to be working perfectly fine and the notion of worrying about dementia feels ridiculous.

It may surprise you to learn that dementia actually begins in the brain decades before troubling symptoms, such as fumbling for words or forgetting where you are, start to show up—maybe even 30 years earlier. As a neurologist and the director of the newly launched Florida Atlantic University Center for Brain Health and Alzheimer’s Prevention Clinic within the Schmidt College of Medicine, I’m here to tell you that the way you live your life right now has the potential to set you up for a lifetime of cognitive health.

Your Brain Health Is in Your Hands

There are four key metrics you can monitor that have a profound effect on your current and future neurological health. These include blood pressure, body composition, blood sugar and cholesterol. As someone with a family history of Alzheimer’s disease (four relatives have been diagnosed), I personally strive to optimize each of these metrics in an effort to keep my brain as healthy as possible.

It’s important to note that when it comes to preventive neurology, what’s considered “normal” versus “optimal” are different. For example, “normal” blood pressure may help keep your heart ticking well into your 70s and 80s, but it won’t necessarily help reduce the risk of dementia as effectively as “optimal” blood pressure might. To determine what optimal looks like for you (it’s different for everyone), I recommend meeting with your doctor for a full health assessment.

That said, there are general numbers to strive for, which I offer in this article. Dementia has not been proven to be preventable in all cases (with the latest evidence suggesting four out of every 10 cases of Alzheimer’s may be preventable based on 12 modifiable risk factors), but taking care of these essential metrics now may pay dividends in the future.

1. Blood Pressure

What’s the link? Elevated blood pressure can damage tiny blood vessels in the brain, which, in turn, can harm the regions in charge of memory, comprehension and more, according to Johns Hopkins University reports. High blood pressure also increases your risk of stroke, a notorious memory saboteur. Strokes can be so small that you don’t even know they’ve happened, but as they add up, your brain ages, paving the way toward dementia.

How does exercise help? Working out is one of the best things you can do to maintain healthy blood pressure. When you’re in the middle of a climb on the Peloton Bike or Peloton Tread, you’re feeling your heart get stronger with every pump, right alongside your quads and abs. The stronger your heart, the easier it is to pump blood throughout your body. The result: lower blood pressure.

General numbers to shoot for Blood pressure is measured as two numbers. The first, called systolic blood pressure, measures the pressure inside your arteries when your heart beats. The second number, diastolic blood pressure, reflects the pressure inside arteries when your heart is resting between beats. The ideal systolic blood pressure is in the 120s or below and diastolic, in the 70s or below. Results from the recent SPRINT MIND study offer impressive evidence that achieving a blood pressure in this range may help delay dementia or mild cognitive impairment (MCI), an early stage of memory loss. Researchers found that reducing blood pressure from the 140s/80s to 120s/70s and below can reduce the likelihood of developing the earliest phases of MCI by 19 percent.

How often should you measure your blood pressure and how do you do it? Have your blood pressure checked by a doctor every six to 12 months. If you have a family history of high blood pressure over age 45, you’ll want to check more often than annually. An old-school DIY blood pressure cuff can also help you keep close tabs on any increases or decreases occurring over time.

2. Body Composition

What’s the link? Body composition refers to the percentages of fat, muscle and bone in a person’s body. For the purposes of this story, let’s focus on fat and muscle.

Body fat: As your belly gets bigger, the memory center of the brain gets smaller. Excess body fat creates an inflammatory environment throughout the body, and that can impact cognitive health. Fat that accumulates around the waist and stomach is especially dangerous. (It also increases risk for heart disease and type 2 diabetes.) This is not to say that all body fat is bad. You need fat for energy, warmth, vitamin absorption, protection from physical injury and more. I’m not saying that Peloton-instructor abs need to be the goal. A flat stomach isn’t possible for everyone. Instead, aim to keep overall body fat at an optimal level and minimize excess belly fat.

Muscle mass: Body fat and muscle mass go hand in hand. As your percent of body fat drops with regular strength training and adequate nutrition, your percent of muscle mass goes up. Muscle mass is highly metabolically active, meaning it helps you burn calories, but it’s also important for keeping your brain young when you hit middle and older age. The average person’s muscle mass naturally drops by about 3 to 8 percent per decade after age 30, leading to a condition called sarcopenia, which may be associated with cognitive decline. Unless you take steps to build or preserve muscle mass, this natural decline is unavoidable. Building up your muscle mass now is an insurance policy against that natural age-related loss in strength.

How does exercise help? Regular aerobic exercise is an excellent way to reduce body fat. During cardio, your body first uses glycogen (stored glucose) for energy, but eventually moves on to using stored fat. I recommend a combination of steady-state cardio (working out at 60 to 65 percent of your max pulse rate for 45 to 60 minutes) and high-intensity interval training (HIIT) two to three times a week. Strength training is just as crucial—remember, muscle powers your metabolism—so, if you’re able, don’t forget the weights and Peloton Bootcamp classes twice a week. I understand working out five (or even six) days a week might not be in the cards for everyone and you should always check with your doctor to determine what's best for you. But again, we’re talking about what's optimal here, meaning best case scenario or when all the stars align.

General numbers to shoot for Exact numbers vary depending on your age and fitness level, but in general, women should aim for a body fat percentage below 30 percent and men below 20 percent. (Note: Body fat percent is not the same as body mass index.) In our Alzheimer’s Prevention Clinic, we advise our patients at risk to aim closer to 27 percent and 17 percent, respectively.

How often should you measure your body composition and how do you do it? Every six months is reasonable. Your doctor or physical therapist may be able to do it. An easy, at-home way to roughly assess body fat is to track your waist circumference. A 2019 study published in the journal Obesity looked at more than 870,000 Korean men and women aged 65 and up and found that those with normal weights but larger waist sizes (35.5 inches or more for men, 33.5 inches or more for women) were at a higher risk of dementia after 6.5 years. Ask your health care provider for help identifying the optimal waist circumference for your body frame.

3. Blood Sugar

What’s the link? Some researchers now call Alzheimer’s disease “diabetes of the brain” or “Type 3 Diabetes,” because poorly controlled blood sugar levels are known to have a major impact on long-term cognitive functioning. When your blood sugar is consistently elevated—often due to a poor diet, too little exercise and weight gain—your body churns out excess insulin, a fat storage hormone. As insulin increases, inflammation throughout the body and brain rises too. You become more at risk for pre-diabetes and diabetes, and people with diabetes have twice the risk of dementia compared to those without. Too much insulin essentially presses the fast-forward button on memory loss.

How does exercise help? Exercise makes your body more sensitive to insulin, meaning your cells can use glucose more efficiently, helping reduce overall levels circulating in your body and brain. A single workout can lower your blood sugar for 24 hours or more, according to the American Diabetes Association.

General numbers to shoot for Between 70 mg/dL and 99 mg/dL is considered normal, but if you’re truly looking to optimize your long-term brain health, ask your doctor for a more precise goal tailored to your own personal and family health history. You can also check your hemoglobin A1C level, which measures your average blood sugar levels over the past three months (whereas a basic blood sugar reading is a snapshot of your blood sugar at the moment the blood was drawn). A “normal” A1C level is below 5.7 percent, according to the CDC, but again, more optimal may be closer to 5.4 or below.

How often should you measure your blood sugar and how do you do it? Ask your doctor about fasting blood sugar and A1C annually if you’re young and in good health. If you have risk factors for diabetes, are overweight or are concerned about your cognitive health, ask your doctor to help you craft a more frequent testing schedule.

4. Cholesterol

What’s the link? Elevated cholesterol levels won’t increase dementia risk in everyone, but if you have personal or family-related risk factors, it can certainly put you on a fast track toward developing it. Cholesterol, specifically low-density lipoprotein (LDL), is a waxy substance that builds up in the blood. Some of it is made by the body and some of it comes from meat, cheese and other animal-based foods. A certain amount of cholesterol is critical for healthy cell functioning and hormone production, but too much can clog arteries, depriving organs like the brain from nourishing, oxygen-rich blood. Despite what many people think, you don’t have to be overweight to have high cholesterol. Family history and diet hold a lot of sway.

How does exercise help? Getting your heart pumping on a regular basis helps clear LDL cholesterol from the blood. It does this by increasing a healthy type of cholesterol called high-density lipoprotein (HDL), often called “the good cholesterol,” which ferries artery-clogging LDL away from the arteries.

General numbers to shoot for Women and men aged 20 and older should aim for total cholesterol levels between 125 mg/dL and 200 mg/dL. In our clinical practice, LDL targets of less than 100 mg/dL (for both women and men) are often used as a general goal. However, especially for people at higher risk, we now more commonly incorporate a more precise metric called ApoB cholesterol to optimally tailor a person’s individual goal. Again, if you have personal or family risk factors that increase your likelihood of developing heart disease, diabetes or dementia, your primary care doctor or preventive cardiologist may want to further individualize your numbers.

How often should you measure your cholesterol and how do you do it? Healthy adults should have their cholesterol checked at least every few years. Have a history of disease? You’ll want to have it checked more often; ask your doctor for guidance.

Richard S. Isaacson, MD is a neurologist and clinician-researcher who specializes in Alzheimer’s disease (AD) prevention and treatment; he is also a paid consultant member of the Peloton Health & Wellness Advisory Council. Dr. Isaacson is currently the director of the newly launched Florida Atlantic University Center for Brain Health and Alzheimer’s Prevention Clinic within the Schmidt College of Medicine. He is committed to using technology and lifestyle interventions, such as physical exercise and nutrition, to optimize patient care, AD risk assessment and early intervention. For more on what you can do to support brain health, check out Dr. Isaacson’s free online video course.

This content is for informational and educational purposes only and does not constitute individualized advice. It is not intended to replace professional medical evaluation, diagnosis, or treatment. Seek the advice of your physician for questions you may have regarding your health or a medical condition. If you are having a medical emergency, call your physician or 911 immediately.