When your bones age, they lose mass and density. When your muscles age, they lose strength and power. When your skin ages, it wrinkles and sags. What happens when your brain ages? A lot.
Shrinkage. Starting at around age 40, your brain starts to shrink—particularly in the prefrontal cortex and hippocampus, areas vital to memory and decision-making.
Neural damage. Brain cells (neurons) shrink in size. There are fewer dendritic branches, the connections between neurons that receive signals. Myelin—the fatty sheath that protects axons, the structure that transmits signals between neurons—decays. This slows down electrical signaling between not only between brain cells, but also between brain regions.
Fewer neurotransmitters. There is a decline in the level of neurotransmitters, the brain chemicals that send messages from neuron to neuron. Dopamine—a must for motivation, decision-making and planning—drops 10 percent per decade, starting in your twenties. Acetylcholine decreases, leading to memory loss. Serotonin and norepinephrine decrease, impeding your ability to focus. You also have lower levels of brain-derived neurotrophic factor (BDNF), which helps the brain form new neural connections (neuroplasticity).
Reduced blood flow. There is less blood flow to the brain, cutting the level of nutrients and oxygen, which in turn decreases brain energy and the rate of brain repair.
Damaged mitochondria. These microscopic energy-generators in neurons become less efficient at producing energy, making the brain more vulnerable to stress and toxins.
Neuroinflammation. The age-related increase in neuroinflammation—inflammation of the brain—slows repair and speeds neurodegeneration.
All of these age-based changes diminish your cognitive function and cognitive skills. You suffer memory loss, both your episodic memory of events and experiences, and your working memory, which stores and uses information to help you think and learn. Mental processing—acquiring, storing, interpreting, and using information—slows down. You have a diminished ability to focus and problem-solve, and to multitask. Neuroplasticity weakens—it takes more effort and repetition to form new mental connections.
What are the ways you can slow brain aging? A remarkable new study points toward the answers.
Three top risk factors for brain aging
The study was conducted by an international team of researchers and published in Nature Communications in 2024. [https://pubmed.ncbi.nlm.nih.gov/38538590/] Previously, the researchers had identified a network of vulnerable brain areas—dubbed the “weak spot”—which degenerate first and fastest as we age. [https://pubmed.ncbi.nlm.nih.gov/25422429/] Now, the researchers analyzed the brain scans of 40,000 people aged 45 and over. They also analyzed their genetic and personal health data. Comparing the scans with the data, they determined the genetic and lifestyle factors that drive the aging of the weak spot.
For the analysis, the researchers grouped 161 risk factors into 15 categories: blood pressure, cholesterol, diabetes, weight, alcohol consumption, smoking, depressive mood, inflammation, pollution, hearing, sleep, socialization, diet, physical activity, and education. The top three risk factors for accelerated brain aging were:
- Type 2 diabetes
- traffic-related air pollution
- frequent alcohol intake
How to shift an aging brain into reverse
There are many ways to help prevent, control or reverse each of these three leading risk factors for brain aging.
Diabetes
The chronically high levels of blood sugar (glucose) in type 2 diabetes (T2D) are very harmful to the brain. To balance blood sugar:
Control stress
The development of T2D often begins with chronic stress, which triggers the release of cortisol, a stress hormone that spikes glucose. At the same time, stress restricts blood flow, limiting the movement of glucose to the brain—an organ that is 2 percent of the body’s weight but demands 20 to 25 percent of the body’s glucose. To help control stress, try a science-supported, brain-balancing breathing technique called Contralateral Nostril Breathing (CNB).
The technique—used by yogis for thousands of years, and scientifically verified at Stanford University and other institutions—works because the two nostrils and the two hemispheres of linked. The left nostril is related to the right hemisphere of the brain (diffuse, dreamy, and creative). The right nostril is related to the left hemisphere of the brain (focused, alert, and analytical).
To balance your brain and reduce stress, do CNB for 5 to 10 minutes daily:
- Sit comfortably with your spine straight and shoulders relaxed.
- Take a few deep breaths to center yourself.
- Close the right nostril with your thumb.
- Inhale through the left nostril slowly and deeply.
- Close the left nostril with your ring finger.
- Release the right nostril and exhale through the right nostril.
- Inhale through the right nostril, keeping the left nostril closed.
- Close the right nostril again and exhale through the left nostril.
Say no to refined sugar
Consuming refined sugar triggers high levels of insulin, the hormone that moves glucose out of the bloodstream and into cells. Eventually, the cells say, “I can’t take this anymore,” and they block insulin, which leads to higher levels of glucose in the bloodstream. This condition is called insulin resistance. It affects 70 to 80 million Americans, and is the precursor to T2D. Refined sugar also causes inflammation, which drives the development of T2D. There are very few absolute no’s in lifestyle—but refined sugar is one of them. Avoid it like poison. Try to avoid refined flour, too.
Do high-intensity interval training (HIIT)
High-intensity interval training is a workout that alternates short bursts of vigorous activity with periods of low-intensity recovery or rest. Research shows that HIIT is particularly effective for controlling T2D—lowering HbA1c (a measurement of long-term blood sugar control), lowering blood glucose levels, and improving insulin resistance.
A typical session includes:
- Warm-up: 3–5 minutes of gentle movement
- High-intensity intervals: 20–60 seconds each
- Rest or low-intensity recovery: 30–90 seconds between efforts
- Repeat: 4–10 intervals depending on your fitness
- Cool-down: 3–5 minutes of light movement and stretching
Consider these three glucose-controlling supplements
Supplementing the diet with the mineral chromium can help regulate the uptake of glucose. A teaspoon or two of high-fiber psyllium with a meal can slow down absorption, helping to balance blood sugar. The herb berberine—which has a mechanism of action similar to the diabetes drug metformin—is a useful supplement for someone with insulin resistance.
Traffic-based air pollution
Research links this type of air pollution to brain aging, neurodegeneration, cognitive decline, and Alzheimer’s disease. The pollutants that do the dirty work include nitrogen dioxide from gasoline and diesel engines, carbon monoxide, ozone, fine particulate matter (PM2.5), and ultrafine particles (UFPs). To minimize exposure:
Use an air purifier
Traffic-related air pollution can easily enter and accumulate in your home, where people typically spend more than 90 percent of their time. That’s especially true if you live near busy roads, highways, or urban centers. To counter indoor air pollution, use an air purifier equipped with both a HEPA filter and a high-quality activated carbon filter. These two filters work together to adsorb gaseous pollutants like nitrogen dioxide and capture particulate matter.
Take off your shoes at the door
Shoes track in a wide variety of outdoor pollutants, including those from vehicle emissions.
Enjoy olive oil
Several studies show that consuming olive oil reduces arterial inflammation from particulate matter found in air pollution. And less inflammation in the heart means less inflammation in the brain. Writing in Environmental Health Perspectives, researchers called olive oil “an efficacious intervention” to protect against air pollution.
Frequent alcohol intake
What does “frequent” mean? If you’re drinking a couple of times a year, alcohol intake won’t have any significant effect on your brain. If you’re having a couple of hard drinks several times a week—you have to stop. But even one drink a day may be too many, with recent research linking that level of intake to cancer. Other ways to think about limiting alcohol consumption:
Use alcohol as a medicine, not a beverage.
For example, if you have a crippling back spasm, half a glass of dark beer can do wonders. It’s rich in hops, and delivers B vitamins and magnesium, all of which are relaxing. That’s good medicine for tense muscles.
Treat alcohol use disorder (AUD) with a holistic approach.
There are many dimensions to AUD—an impaired ability to stop or control alcohol use, in spite of its negative effect at home and at work, and on your health—and effective treatment addresses them all.
For example, in AUD glucose metabolism is also disordered, and sugar addiction is common. Trauma is a factor in 70 to 80 percent of cases, with alcohol used as a depressant to suppress emotional states that are terribly uncomfortable. And there are often familial and cultural factors, requiring social support. Without addressing all the factors that contribute to AUD, successful treatment is difficult.
