Like it or not, aging happens. Our bodies are not as quick or agile as they once were.

 

Our brains age in similar ways. You may not think as quickly as you used to; multi-tasking and mental agility become more challenging. And you’d swear your keys sprouted legs and walked off to hide from you!

 

These age-related changes in how we think, process and remember are part of Cognitive Aging. Though it manifests differently for every person, cognitive aging is normal, and changes need to be accepted. That said, there’s a lot we can do as we age to optimize cognitive function just as we do to stay physically fit. In fact, physical fitness and mental fitness are intimately related.

 

Which functions are affected by Cognitive Aging?

Processing Speed: 

How quickly can you process information and respond physically or provide an answer?  Processing speed affects just about every brain function. It is not a specific mental task; it’s about how quickly you can manage a cognitive task.

Memory:  

There are many types or categories of memory. Of the types affected by cognitive aging, the most impactful are changes in working memory, prospective memory, and retrieval.

  • Working memory temporarily holds information in consciousness manipulates it for problem-solving and decision making.  This is a complex process related to executive functioning. An example would be keeping a person’s address in mind while listening to instructions for getting there.
  • Prospective memory is about remembering to do things in the future, like remembering to stop at the grocery store on your way home from work. We all have our strategies for addressing this type of memory lapse!
  • Recall and Retrieval:  Because of slower processing speed, you may need more time to find a word or a name or other specifics in your memory bank.  “It’s on the tip of my tongue," you hear yourself saying more frequently.

Learning:

While older people are completely capable of learning new things and integrating new information, it may just take more time and some repetition. 

Attention:

While sustained attention to a task or a presentation is not typically affected by aging, we can expect challenges with attention requiring more mental agility.

  • Selective attention: focusing on something specific and filtering out distractions as on a complicated menu or in conversation with a person at a loud restaurant. 
  • Divided attention: the ability to manage multiple tasks or streams of information at the same time. Multi-tasking or switching between agenda items.

Executive Function:

Is not notably impaired until a person reaches their 70’s or 80’s. (1)

Executive function includes planning, organizing, decision making, reasoning and adapting to new situations. Interestingly it also regulates behavior and keeps us from acting in socially inappropriate ways.

 

How does the brain change as it ages?

 

The decline in cognitive abilities described above reflects changes in the brain’s structure and chemistry. These changes are slow and subtle; though some begin as early as 30 years old, they may go unnoticed until we reach 60 or 70. 

The frontal lobes and the hippocampus begin to shrink in middle age. (2).  These areas of the brain support executive function, learning and the encoding of new memories. 

Neurons shrink and retract some of their dendrites, so where a nerve cell might have had branched connections to 100 other neurons, it eventually has only 50. The myelin layer that wraps and protects the neurons begins to break down as well.

The cerebral cortex - the brain's outer layer containing nerve cell bodies - becomes thinner, particularly over the frontal lobes. Thinning is due to the decline in the neurons described above.

Our brains generate fewer neurotransmitters as we get older. These are the chemicals that transmit impulses from one neuron to another across the synapses. Dopamine, serotonin, acetylcholine, and norepinephrine can all be affected. 

Finally, inadequate blood circulation to the brain can also affect the health and vitality of brain tissue. Hypertension, cigarette smoking, and inactivity can advance normal cognitive aging and contribute to an actual decline toward dementia. 

 

How does exercise benefit the brain?

Can we slow the process of Cognitive Aging? In most cases, the answer is a resounding Yes!  Exercising regularly is one of the most effective ways to promote healthy brain function. 

Simply put, the brain thrives on challenge and stimulation. The more active and positively engaged we are, the stronger the brain will be. For optimal cognitive and mental health (mood regulation), we should strive to be mentally active, socially engaged and physically active.

 

Exercise increases Circulation:

The brain receives about 15% of the body’s blood supply, even though it comprises only 2-3% of total body mass. (3)  Nerve cells need continuous oxygen to function and survive, so the brain requires a healthy network of blood vessels to supply it.

During exercise, the body drives more blood and oxygen to the brain,  stimulating the growth of new blood vessels. Regular exercise improves the health and function of the existing circulatory network as well. 

There is also evidence that exercise increases mitochondrial activity in the brain - at least in mice. (4)  Mitochondria are the structures in all cells that supply their energy. The demand for more power is answered with more power! Adequate aerobic exercise helps ensure your muscles and your brain have the fuel they need to meet all their demands.

Regular exercise also helps prevent hypertension. What’s good for the heart is good for the brain!

 

It Increases Neurotransmitters:

Physical activity stimulates the release of endorphins, dopamine, serotonin and norepinephrine. (5) These chemicals are required for neurons to communicate across the synapses, and they promote healthy mood regulation as well.

 

Maintains Memory:

Research suggests that exercise helps preserve our memory functions because it slows the shrinkage in the hippocampus described earlier. In fact, one study showed shrinking was actually reversed in older people just by regular walking! (6) Remember, the hippocampus is involved in learning new information and encoding new memories.

In this study, the shrinking was correlated with increased brain-derived neurotrophic factor (BDNF) in the blood.  BDNF is linked with brain plasticity (ability to change and adapt from experience) and neurogenesis (creating new neurons) in the hippocampus.

 

Reduces Inflammation:

As we age, normal immune function starts to decline and chronic low-level inflammation affects our organs. In the brain, the microglial cells are our protectors. They continually search for potential threats from foreign microbes and damaged cells and remove them. Later in life, the microglia typically become slower and less efficient (like everything else). Without their activity, inflammation can set in and impair cognitive function.

Aine Kelly, Professor of Physiology in Dublin, asserts, “Recently, we’ve shown that exercise can reprogram microglia in the aged brain. Exercise was shown to make the microglia more energy-efficient and capable of counteracting neuroinflammatory changes that impair brain function.” (7)

 

 

What kind of exercise helps cognitive function?

By now, I hope you’re well motivated to move your body and support your brain. And you may be wondering what type of exercise is best.

 

Research findings to date suggest that a combination of aerobic exercise - getting your heart rate up - and strength training is most effective. 150 minutes per week of moderate exercise (that’s 5 30-minute sessions) is sufficient to maintain general health and slow cognitive aging. (8)

 

And, if possible, it should be a type of exercise you enjoy. Endorphins flow even more freely when activity is fun. These are also neurotransmitters - important for brain health. If you don’t enjoy running on a treadmill or walking the streets of your neighborhood, plug in some music to energize you and make you smile!

 

Dancing is apparently the best exercise for brain health (9). This is not surprising, since it incorporates aerobic exercise, balance, coordination and (often) patterned movement. It may also provide social connection and stimulation so vital to our mental and cognitive health. That said, dancing alone in one’s living room should not be underrated!

 

 

We hope that if you understand what cognitive and physical changes to expect with aging, you can learn acceptance and have some compassion for yourself. Everyone ages differently. Though most of us are still perfectly functional, we do lose speed and agility in a world that does not slow down for us. It’s not about staying young or combatting aging; it's about making the best of things as they are. Exercise makes aging better. Get out there and enjoy!

 

If you have more questions about aging well, don't hesitate to contact us at Austin Functional Wellness.

 

In part 2 of this series (10/2021), we’ll discuss neurocognitive testing and  Dr. Austin’s favorite brain-training tools. Stay tuned!

 

Notes:

1. https://betterhealthwhileaging.net/how-brain-function-changes-with-normal-cognitive-aging/

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2596698/

3. https://theconversation.com/exercise-and-the-brain-three-ways-physical-activity-changes-its-very-structure-150203

4. https://www.quickanddirtytips.com/education/science/how-exercise-jogs-brain

5. https://www.healthline.com/health/depression/exercise

6. https://theconversation.com/exercise-and-the-brain-three-ways-physical-activity-changes-its-very-structure-150203

7. https://theconversation.com/exercise-and-the-brain-three-ways-physical-activity-changes-its-very-structure-150203

8. https://www.mayoclinicproceedings.org/article/S0025-6196(11)62235-0/fulltext

9. https://www.medicalnewstoday.com/articles/319185#Therapies-to-help-slow-brain-aging