The New "Normal" of Brain Aging
- Published8 Aug 2019
- Author Alexis Wnuk
- Source BrainFacts/SfN
An estimated 46 million people worldwide have Alzheimer’s disease, the most common form of dementia. That number is expected to double every 20 years as the population ages and life expectancy increases. But, while aging is inevitable, disability and dementia are not. In fact, neuroscientists believe our brains can remain relatively healthy as we age.
Aging involves subtle changes in brain structure, chemistry, and function that commonly begin in midlife. By the time we reach our 60s and beyond, our brains are usually smaller in size, with decreased blood flow and lower levels of neurotransmitters and hormones. Synapses — the junctions at which brain cells communicate — also weaken as we age.
Although the brain loses some neurons as we grow older, the losses aren’t as dramatic or as widespread as scientists once thought. Likewise, pronounced declines in memory and cognitive abilities are no longer considered natural consequences of the aging process. We now know they’re symptoms of disease processes like dementia, a severe and progressive decline in memory, communication, and thinking.
Nonetheless, some mental decline is normal. Some studies suggest cognition starts declining as early as the 20s and 30s, while other studies indicate cognition improves into the 50s or 60s before declining. A growing area of research focuses on understanding how lifestyle choices such as diet and exercise can support cognitive health throughout life.
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