Aging

When Does Brain Aging Start? The Answer Might Surprise You

The hidden benefits of prioritizing brain health early in life.

Posted Feb 16, 2020

vs148/Shutterstock
Source: vs148/Shutterstock

How often do you forget why you walked into a room or have difficulty recalling a word you want to say? Many people begin to notice an increase in such “brain blips” in their 50s and beyond. Luckily, most brain blips are common and are not a sign of a more concerning memory problem. The silver lining of brain blips is they often increase awareness of cognitive functioning, and boost motivation to engage in brain-healthy behaviors. 

However, growing research suggests we shouldn’t wait for “brain blips” or other cognitive concerns to occur before we start to focus on brain-healthy activities. In fact, although the majority of research on brain health has been conducted on adults who are middle-aged and older, exciting new research shows that even mid-life brain health can be boosted by engaging in specific activities in the 20s and 30s—decades before brain health is top of mind for most people. This may relate to the finding that cognitive skills actually begin to decline at younger ages than expected. 

For example, on neuropsychological tests (which allow for the precise measurement and tracking of cognitive abilities, or “thinking skills”) most people already show declines in spatial visualization and spatial reasoning by the mid-twenties. Declines in memory and reasoning are present by the early 30s, and declines in the speed of information processing are evident by the mid-thirties. Although these declines are initially subtle, they add up with each passing decade and often become more noticeable after age 50, around the time “brain blips” start to become more apparent. 

Interestingly, the rate of brain aging in the 20s and the 30s is related to the rate of aging in other bodily systems. In an innovative study that examined the “Pace of Aging” in young adults ages 26 to 38, those who aged at a more rapid rate across several bodily organs and systems (lungs, heart, dental, kidney, liver, and immune) as compared to their chronologically-predicted rate of aging showed greater cognitive decline and brain aging even by the age of 38. They also reported worse health and were judged to look older than those with a slower pace of aging. 

What types of activities in young adulthood have been shown to impact brain health and cognitive functioning in midlife? A series of innovative studies followed over 3,000 young adults ages 18 to 30 for 25 years to find out. Several valuable insights emerged:

1. A cognitively challenging occupation boosts future brain health. 

Younger adults rated their occupational complexity on the following items, using a scale from 0 to 7 (with higher scores indicating greater occupational cognitive complexity):

  • Judging qualities of things, people, and services
  • Evaluating information against standards
  • Processing information
  • Analyzing data or information
  • Making decisions and solving problems
  • Thinking creatively
  • Updating and using job-relevant knowledge
  • Developing objectives and strategies
  • Scheduling work and activities
  • Organizing, planning, and prioritizing

Those with the highest levels of work-related cognitive activity had faster information processing speed, better mental flexibility, and healthier brain structure 25 years later. Because this research is correlational and doesn't allow us to conclude that a more cognitively demanding job caused better brain health (for example, it's possible that younger adults with stronger brain functioning to begin with simply chose more cognitively demanding occupations), other research has suggested that cognitively complex activities promote better brain health for people across a range of intellectual levels. The brain-boosting effect of cognitively complex activities likely relates to the concept of cognitive reserve, which explains that brain-healthy activities can bolster future brain functioning in the context of normal age-related changes and even in the presence of diseases such as Alzheimer’s or other types of dementia.

2. What’s good for the heart is good for the brain. 

Younger adults with stronger cardiovascular health and higher rates of physical activity in their 20s and 30s had significantly stronger cognitive functioning 25 years later than those who didn’t. Engaging in physical activity that brings you joy is a great way to increase the likelihood that it will become a lifelong habit that boosts not just brain health, but also bodily health, mood, sleep, and quality of life.

3. Lower levels of television viewing are linked to stronger future cognitive functioning. 

Adults in their 20s and 30s who watched television for more than three hours per day had significantly lower information processing speed and mental flexibility 25 years later than those who watched less than three hours per day. Furthermore, those who watched high levels of television and had low levels of physical activity were twice as likely to have lower cognitive functioning 25 years later compared with those who watched low levels of television and had high physical activity. 

All three of these factors had been previously shown to impact brain health for middle-aged and older adults. And, although it was suspected that these findings might also apply to younger adults, it hadn’t been demonstrated until recently. These findings also dovetail with the growing focus in Alzheimer's research on the value of brain-protective behaviors in the “pre-symptomatic” period—those decades before there are any cognitive concerns or symptoms of Alzheimer's. This is especially important given that the earliest Alzheimer’s-related cellular abnormalities are present more than 30 years prior to diagnosis. (And, although we know that lifestyle factors are only one significant contributor to Alzheimer's, they are the only factor we have direct control over; in fact, a healthy lifestyle can significantly delay the expression of Alzheimer's symptoms, sometimes by more than 10 years). 

There is also growing research that establishing brain-healthy habits in childhood makes it more likely that those habits will be continued (and built upon) throughout all stages of adulthood. For now, what the research makes clear is that whether you are in your 20s, 100s, or anywhere in between, it's possible to significantly enhance your future brain health and minimize the risk of Alzheimer's, whether or not you have current cognitive concerns. By prioritizing brain health as a lifelong pursuit, we become empowered (and empower others) to create the best future for ourselves and our next generations. 

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References

Belsky, D. W., Caspi, A., Houts, R. et al. (2015). Quantification of biological aging in young adults. PNAS, 112(30). https://doi.org/10.1073/pnas.1506264112

Kaup A. R., Xia F., Launer L. J., et al. (2018) Occupational Cognitive Complexity in Earlier Adulthood is Associated with Brain Structure and Cognitive Health in Mid-Life: The CARDIA Study. Neuropsychology, 32(8), 895-905.

Hoang T. D , Reis J., Zhu N., et al. (2016). Effect of Early Adult Patterns of Physical Activity and Television Viewing on Midlife Cognitive Function. JAMA Psychiatry, 73(1),73-9. 

Reis, J. P., Loria C. M., Launer L. J., et al. (2013). Cardiovascular health through young adulthood and cognitive functioning in midlife. Ann Neurol. 73(2):170-9.

Salthouse, T. A. (2009). When does age-related cognitive decline begin? Neurobiol Aging. 30(4):507-14. 

Younes, L., Albert, M., Moghekar, A., Soldan, A., Pettigrew, C., & Miller, M. I. (2019). Identifying changepoints in biomarkers during the preclinical phase of Alzheimer’s disease. Frontiers in Aging Neuroscience 11: 74.

Zeki Al Hazzouri, A., Elfassy T., Carnethon M. R., Lloyd-Jones D. M., & Yaffe K. (2017). Heart Rate Variability and Cognitive Function In Middle-Age Adults: The Coronary Artery Risk Development in Young Adults. Am J Hypertens.31(1):27-34. 

Zhu N., Jacobs D. R. Jr, Schreiner P. J., et al. (2014). Cardiorespiratory fitness and cognitive function in middle age: the CARDIA study. Neurology.  82(15):1339-46.