29)Research shows that cognitive functions like learning, memory, and higher-level thinking and decision making take a considerable hit as you get older. The areas of the brain responsible for those functions—the medial temporal lobe (hippocampus) and prefrontal cortex—are also susceptible to depression and stress, which can amplify age-related cognitive decline. Thankfully, you can keep your brain young and healthy by adopting lifestyle changes that protect against depression and stress.
People in late life are more prone to depression, which can cause stress, trigger pain, aggravate chronic conditions, and age your brain. Evidence, including a 2010 study in the journal Psychiatry Research, suggests that major depressive disorder can have harmful and lasting effects on cognitive function. A 2010 study in the British Journal of Psychiatry did brain scans on people over the age of sixty who had major depression and found that cognitive deficits due to depression most likely stem from blood vessel damage in the brain (the scarring results in white matter lesions [?28]). Depression especially affects your ability to understand language and process information quickly, making you feel fuzzy-headed, according to a 2010 study in Neuropsychobiology. And mild depression can trigger brain changes as well, so even if you’re just feeling a little blue, it’s worth taking steps to deal with the depression before it does too much damage.
Whether you are depressed, think you might be, or are concerned about keeping depression at bay as you get older, your first step is to talk to your doctor about lifestyle changes that can protect against depression and even help lift it. For example, countless studies demonstrate exercise’s ability to stimulate endorphins, those feel-good neurotransmitters, and boost mood. A 2006 study by Canadian researchers suggests that exercise might also alleviate depression by stimulating new neurons. Exercise can help you hang on to functional ability longer as well, allowing you to stay active, live independently, and maintain social connections—all of which can help you ward off depression. “Staying socially engaged, whether that’s going to church or taking a class, is one of the best tools to combat depression,” notes Sarah Lovegreen, M.P.H., health manager with OASIS, a national organization that promotes lifelong learning and service for adults age fifty and older. “We’re social creatures…we don’t live in isolation.” (29)
If these strategies don’t suffice, talk to your doctor about medications that might help. Be sure to discuss potential side effects (73), since those can significantly affect your quality of life.
Moderate amounts of stress hormones can actually improve cognitive function and memory, but exposing your brain to too much for too long can mess with your mind. The hippocampus, the area of your brain responsible for long-term memory and spatial navigation, has more glucocorticoid receptors (for stress hormones, such as cortisol) than other parts of the brain, making it more vulnerable to chronic stress. As you get older, your hippocampus undergoes changes—such as losing synapses and having them become less responsive—and adding stress to the picture accelerates that brain aging, affecting memory and your speed of processing information. Stress hormones may also kill brain cells and shrink your hippocampus.
But keeping anxiety in check appears to undo stress-related damage and helps keep your brain working at its best. A 2010 study in the Journal of Neuroscience noted that counteracting cortisol restores spatial memory, keeps synapses adaptable to taking in new experiences (called plasticity, which is the basis for learning and memory and typically declines with age), and helps neurons in your hippocampus fire properly.
Simple strategies (18, 56, 61, 85, 97) can help you subdue stress and “get your brain back.” As with depression, having friends to turn to in difficult times is key. Take a deep breath, or try breathing exercises (4); people often breathe shallowly when stressed, and lack of oxygen for the brain can affect your memory and damage your hippocampus. And try keeping a calendar or to-do list to stay focused: Decision making and planning are use-it-or-lose-it components of cognitive health, and having a plan for the day can help you feel more in control.