During the natural aging process, the brain’s structure and functional ability change. Age-related changes in the brain occur even in a healthy adult, and can lead to a gradual decline in cognitive function. Below, we outline what happens to an aging brain.
The Brain Shrinks
Structurally, the brain shrinks as it ages. Studies suggest that brain shrinkage (scientifically termed brain atrophy) is due to the progressive death of brain cells. Some brain regions are more vulnerable to cell death and brain shrinkage than others; this varying degree of vulnerability partially explains why aging impacts some aspects of brain function more than others.
The timing of normal age-related brain decline roughly coincides with that of other organ systems: Changes begin to occur around the third decade of life, with a notable acceleration after age 50. While there is an expected slowdown in brain function with aging, research indicates that those who develop mild cognitive impairment will experience more accelerated changes in the structure and function of the brain over time. In fact, the rate of brain atrophy during aging is believed to be predictive of future cognitive impairment and dementia.
So what influences the rate of atrophy? Genetics play a part, but environmental factors can also influence age-related decline. Aerobic exercise, for example, has been shown to increase the size of certain parts of the hippocampus, whereas excessive caloric intake and obesity can accelerate brain atrophy.
Atrophy is one hallmark of an aging brain. We break down six others below:
- Mitochondrial dysfunction
- Oxidative damage
- Impaired energy metabolism
- Decreased hormetic responses
- A lack of neurogenesis