How Your Brain Changes with Age
Discover the truth about how your brain functions over time—and the everyday habits that can delay its decline.
From the time we are infants, our brains are adapting, learning, and making memories. In fact, our brain changes more than any other body part throughout our lifetime.
Scientists used to believe brain development was finite, occurring rapidly in childhood, peaking in the early 20s, then levelling off in middle age before declining. We now know that the brain is continuously changing as we age, with some areas getting weaker while others get stronger.
A report published by Harvard Health showed that the brain shrinks—especially those areas important to learning and complex mental activities—at a rate of 5% every decade after the age of 40, possibly even faster after 70. As we age the protective myelin sheath that wraps around nerve fibers also wears down, causing slower communication between neurons. And if inflammation increases, research has shown that blood flow may also decrease.
The most common cognitive change that happens with aging, however, is memory loss, such as not being able to easily recall names and numbers, misplacing keys, etc. This begins to decline at age 20. Other changes include difficulty learning new things because it takes longer to memorize new information, plus the inability to multitask due to slower processing. Although these brain changes may sound a bit scary, the process, say experts, is normal and happens to everyone.
On a positive note, there’s growing evidence that the brain’s continued ability to change and evolve enables us to manage new challenges and respond better to life experiences. This adaptability, called neuroplasticity, can be thought of as a structural remodeling of the brain. In response to stimulation, such as learning something new daily, doing The New York Times’ puzzle, or even playing Words with Friends, nerve cells generate new connections which allow greater mental and behavioral flexibility. In addition, certain parts of the brain can generate new cells throughout life in a process known as neurogenesis--something scientists long believed was impossible.
Neurogenesis and neuroplasticity work together. The more neurons communicate together, the stronger their connection. As a result, branching connections between distant brain areas strengthen with age, helping you to better dissect varied sources of information, and how they connect to the bigger picture, says the Harvard Health report.
Learning how your brain changes with age will help you better understand what is happening at each stage of your life.
Below, a breakdown of how our brain functions over time and the ways to boost its power as you age.
Infancy and Childhood
The brain begins developing in the third week of gestation, growing incredibly rapidly in the early years. More than a million new neural connections, or synapses, are made every second in the first few years of life. The size of the brain also increases and, by age 6, is around 90% of its adult volume.
Babies are born with basic survival skills, reflexes and most of the 100 billion neurons they will have for life. As a result of environmental input and stimuli, the brain makes trillions of connections to fine-tune everything from hearing to vision. In fact, a child’s brain has twice as many synapses as an adult’s brain. By early to middle childhood, about 85% of brain development has occurred including intellect, personality, motor and social skills.
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During the teen years the brain reaches its adult weight of about three pounds. Increased activity in the frontal lobes allows a teenager to compare several concepts at once.
Late 20s to 30s
In the 20s, areas of the brain responsible for planning, working memory, and impulse control finish developing (although some may not fully develop until the mid-30s). The brain has reached its peak in terms of performance. According to research, reasoning, spatial skills, and speed of thought begin to decline around now. Memory begins to slip in the mid-30s, and it takes longer to learn new things and memorize words or names.
40s and 50s
From the mid-40s to late 50s reasoning skills, sharpness in memory, and verbal fluency decline. Several factors can accelerate brain aging including obesity in midlife, which can speed aging up by about 10 years. Experts have proven that both sugar and diet soda are also associated with a decline in brain health. On a positive note, moral decision-making, regulating emotions, and interpreting social situations improve during middle age.
After a lifetime of accumulating knowledge, the brain can become less efficient at accessing or adding to it. The greatest risk factor for Alzheimer’s is advancing age, most common at 65 or older.
70s, 80s, and Beyond
Along with aging, experts believe that genes and lifestyle contribute to most dementia cases. The risk of developing Alzheimer’s reaches 50% by age 85. Researchers aren’t sure why this jumps so dramatically as we age, but think it may be linked to inflammation, a natural part of aging. During these decades, some studies show one-third of older adults struggle with stored memory or events, while other studies indicate that one-fifth of 70-year-olds perform cognitive tests as well as people aged 20. According to the National Institute on Aging, older adults have more extensive vocabularies and greater knowledge of subtlety in word meaning than younger adults. They have also accumulated a lifetime of knowledge and experiences, which contributes to wisdom they can typically share.
Proven Brain Boosters
The good news? Though some change is inevitable, a healthy lifestyle can slow and possibly reverse decline. A growing body of evidence suggests that people who experience the least loss share certain habits: engaging in regular physical activity, pursuing intellectually stimulating activities (like playing a musical instrument), staying socially active, managing stress, eating healthy, and sleeping well.
Break a Sweat
One of the strongest ways to improve neuroplasticity is through physical activity. Studies show that walking an hour a day, five days a week, increases brain matter in the hippocampus (the region responsible for learning and memory). Aerobic activity releases brain-derived neurotropic factor (BDNF). This protein stimulates the growth of new synapses and strengthens the signals transmitted from neuron to neuron. Elevated levels of BDNF are associated with improved mental health and memory whereas decreased levels are seen in neurodegenerative disorders like Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, and Huntington’s.
Keeping your mind engaged with enjoyable mentally stimulating activities, such as reading, writing or solving crossword puzzles, appears to increase brain health and may even reverse cognitive decline. Some of these directly stimulate neuroplasticity: trying new challenges, training your mind with mindfulness meditation, engaging in play and listening to music. Just being in enriched and stimulating environments helps.
Nurture Your Relationships
Social connections help neural connections. Socializing uses areas of the brain involved in memory and attention. Exposing yourself to people with diverse viewpoints also helps the brain develop cognitive flexibility.
The Journal of the American Geriatrics Society found that greater adherence to the MIND diet (a hybrid of Mediterranean and DASH diets focused on plant-based foods) was associated with better cognitive function and a lower risk of impairment.
Foods rich in vitamins and other nutrients also help brain health. Eating vibrantly hued fruits and vegetables, which have prominent levels of disease-fighting antioxidants, helps to counteract disease-causing free radicals that contribute to inflammation. Research by the University of Illinois found that that middle-aged people with higher lutein levels (present in green leafy vegetables, eggs, and avocados) had similar neural responses to younger individuals than to people their own age. Finally, research from Nutritional Neuroscience suggests that specific omega-3 polyunsaturated fatty acids (PUFAs) may support the ability to think and reason abstractly for problem solving by preserving gray matter in cognitively intact older adults.
Drink in Moderation
Drinking alcohol sparingly (one drink for women, two for men) may benefit the brain and reduce the risk of dementia in older adults. However, heavier alcohol use may have the opposite effect and may increase cardiovascular risk.
Smoking affects your body’s ability to deliver oxygen and nutrients to the brain. Some studies indicate that smoking can even speed up the brain’s natural aging process. Smoking can also lead to the formulation of plaques that can contribute to dementia.
Protect Your Head
Experts believe there may be a connection between serious head injury and Alzheimer’s disease, especially when trauma occurs repeatedly or involves loss of consciousness. Protect your brain by wearing a seatbelt, using a helmet in sports, and fall-proofing your home.
Declining brain function over time is normal, but the process can be slowed by life-enhancing changes that improve physical and mental health. Best of all, the lifestyle that supports your brain will also protect your heart.
This article was originally published on September 8, 2021, and has been updated as of the above date.