Other useful strategies that can contribute to your brain health.
For general references (now several years old) summarizing evidence that physical exercise is good for your brain, see Ratey JJ & Hagerman E (2008) Spark: The Revolutionary New Science of Exercise and the Brain. Little-Brown:Boston; or Hillman CH, Erickson KI, Kramer AF (2008) Be smart, exercise your heart: exercise effects on brain and cognition. Nat Rev Neurosci 9:58. For a more recent review, see Bherer L, Erickson KL, Liu-Ambrose T (2013) A review of the effects of physical activity and exercise on cognitive and brain functions in older adults. J Aging Res 2013:2013:657508 (epub).
Scientists have an increasingly clear understanding of the processes that underlie exercise-derived benefits for cognitive and other brain processes. For example, see Voss MV, Vivar C, Kramer AF, van Braag H (2013) Bridging animal and human models of exercise-induced brain plasticity. Trends Cogn Sci 179:525; Mattson MP (2012) Energy intake and exercise as determinants of brain health and vulnerability to injury and disease. Cell Metab 16:706; and the highly recommended Rothman SM, Mattson MP (2013) Activity-dependent, stress-responsive BENF signaling and the quest for optimal brain health and resilience throughout the lifespan. Neuroscience 239:228. Hundreds of studies now support the value of regular exercise for brain (and brain-related body) health.
I have emphasized the importance of mental engagement in exercise, and of variability in movement control in exercise as key aspects of healthy brain engagement. This emphasis comes from an understanding of the basic processes of brain plasticity, which show that it is degraded when actions are stereotypic, and enabled when they can draw on variable inputs and actions in the control of moment-by-moment (and in learning new) action control. We know that these plasticity enabling processes, supported by the convergence of top-down projections from working-memory brain levels AND feed-forward inputs from attention-engaged cholinergic neuromodulatory processes, are progressively degraded in most older brains — and that they are rejuvenated by exercises that re-engage brain machinery with substantially variable sensory-motor challenges. These plasticity-enabling Carcea I & Froemke RC, 2014, Cortical plasticity, excitatory-inhibitory balance, and sensory perception. Prog Brain Res 207:65, for a summary of their operations in the cortex; and Stocco A, 2012, Acetycholine-based entropy in response selection: A model of how striatal interneurons modulate exploration, exploitation and response variability in decision-making. Front Neurosci 6:18 doi:10.3389/fnins.2012.00018 for a corresponding description in the striatum.
As I have emphasized in earlier chapters describing the acquisition of abilities in childhood, scientists have repeatedly shown that the learning brain thrives on variability in translating inputs to actions (not rote, stereotypic exercise). Repetition, stereotyped, ‘automatic’ behaviors shut down the noradrenaline- and acetylcholine-based ‘on switches’ that enable brain change. As long as the challenges in brain engagement CHANGE, try by try, this plasticity-controlling machinery continues to be activated. When repetition results in relatively unchanging feedback or action, this machinery rapidly shuts down.
Many current physical and occupational therapy practices encourage repetitive exercises that, by their nature, limit enduring brain change. Exercise strategies that emphasize ‘feeling the movement’, and that are highly variable and progressive in performance demands (e.g., performing an action at different speeds, reaching a goal from many directions, etc.) more strongly engage the machinery in the brain that controls plasticity. Tai Chi, progressive aerobics or other dance exercises that continuously evolve in difficulty, brain plasticity-informed physical therapists, or the physical therapy practices of the Feldenkrais school of practices (where there is a great stress on movement variability and on sensory integration for movement control) are examples of ‘good practices’ that make neurological sense.
Studies that have documented lifestyle factors that support good brain health have repeatedly put two factors on the list: a) daily physical exercise; and b) dancing. Patricia McKinley (a McGill University professor that we have worked with on brain plasticity issues) has argued that progressive, challenging partners dancing is particularly good for your brain. See for example, McKinley P et al (2008) A community-based Argentine tango dance program improves functional balance and confidence in at-risk older people: a randomized control feasibility study. JAPA 16:435
Studies that have determined the values of ‘those things that you do in everyday life that you think are good for your brain’ have shown that most of them AREN’T much good. For example, we have known for more than a decade that there is no relationship between solving crossword puzzles and cognitive ability in aging. See Hambrick DZ, Salthouse TA, Meinz EJ (1999) Predictors of crossword puzzle proficiency and moderators of age-cognition relations. J Exp Psychol Gen 138:131. Indeed, tasks like this have been applied on the control arms of studies of BrainHQ study efficacy; NO positive changes can be attributed to their use. For example, see Wolinsky et al., A randomized controlled trial of cognitive training using a visual speed of processing intervention in middle aged and older adults. PLoS One 8:361624.For an introduction into the literature relating lifestyle to brain health, see, for example, Mora F (2013) Successful brain aging: plasticity, environmental enrichment, and lifestyle. Dialogues Clin Neurosci 15:45.
While I disagree with its emphasize of the importance of different aspects of brain engagement for keeping your brain in good shape (it de-emphasize direct brain training, which is pretty critical, in my view, for about half of the older human race) the Dana Foundation’s booklet provides lots of good general advice about non-brain-training strategies to keep your brain in good stead at an older age, include easy-to-read advice about exercise & diet. See Staying Sharp. Successful Aging and Your Brain — which you can download at: (http://www.dana.org/uploadedFiles/The_Dana_Alliances/Staying_Sharp/Successful%20Aging%20and%20Your%20Brain.pdf)
Hundreds of books and thousands of articles have been written about the general topic of diet and brain health. Most of them are thinly disguised marketing messages. For a more scientific perspective, I suggest beginning with Mattson MP (2002) Diet-Brain Connections. Impact on Memory, Mood, Aging, and Disease. Kluwer Acad: Dordrecht, Netherlands — and with this decades-old (but enlightening) perspective, moving to more contemporary reviews — for example, Daffner KR (2010) Promoting successful cognitive aging: a comprehensive review. J Alzheimers Dis 19:1101; Martinez-Lapiscina et al. (2013) Mediterranean diet improves cognition: the PREDIMED-NAVARRA randomized trial. J Neurol Neurosurg Psychiat DOI:10.1136/jnnp-2012-304792;
Hundreds of studies have linked adiposity and obesity to cognitive decline — although the chicken vs egg issues in this scientific domain are not completely resolved. For an entry into this literature, you might begin with Shefer G et al (2013) Is obesity a brain disease? Neurosci Biobehav Rev 37:2489. Of course being overweight is synonymous with increased vascular problems long known to contribute to cognitive decline in aging. See, for example, Moll RE et al (2012) Vascular risk factors as treatment target to prevent cognitive decline. J Alzheimers Dis 32:733. One scientist who has focused on the question of the importance of how often and how much you eat (who recommends eating a lot less every other day or so — a strategy that I’ve personally adopted) is Mark Mattson, the leader of a large NIH laboratory. He emphasizes the reversibility of all of that damage coming from a long history of caloric over-consumption, in studies that show direct body-brain links. For example, see Stranahan AM, Mattson MP (2011) Bidirectional metabolic regulation of neurocognitive function. Neurobiol Learn Mem 96:507.
The average number of unique prescriptions/year (not including refills) for individuals between 75 and 85: 6.7. Drug use is steadily growing, decade by decade. About 2/3rds of individuals over 60 now regularly use 3-4 or more prescription drugs; about 40% use 5 or more. Women are a little more likely to use more drugs than men. The more systematic medication of older individuals is contributed to by their more universal access to health care via Medicare. See, for example, Gu Q. et al (2010) Prescription drug use continues to increase: U.S. Prescription rates for 2007-2008. NCHS Data Brief 42 (http://www.cdc.gov/nchs/data/databriefs/db42.htm)
There is a substantial body of evidence that has shown that meditation can improve human abilities in ways that we know are accounted for by plastic (brain) change. For an entre to this literature, for example, see MacLean KA et al (2010) Intensive meditation training improves perceptual discrimination and sustained attention. Psychol Sci 21:829. The neurological bases of these effects is increasingly well established. For example, see a study from the laboratory of a former fellow in my laboratory, Christopher Moore (Kerr CE et al, 2011, Effects of mindfulness meditation training on alpha modulation in primary somatosensory cortex. Brain Res Bull 85:96. This group has also shown that mental exercise alone results in positive changes in the physical brain (e.g., see Lazar SW et al, 2006, Meditation experience is associated with increased cortical thickness. Neuroreport 16:1893; or Holzel BK et al, 2011, Mindfulness practice leads to increases in regional brain gray matter density. Psychiatry Res 191:36. These strategies have been effectively applied clinically to help patients with all kinds of brain-related problems. For example, see Bushnell MC et al (2013) Cognitive and emotional control of pain and its disruption in chronic pain. Nat Rev Neurosci 14:502. For an overall review of this important subject to ‘mind training’, see Davidson RJ & McEwen BS (2012) Social influences on neuroplasticity: stress and interventions to promote well-being. Nat Neurosci 15:689.Even while it may be difficult for you to move your body, you still have great powers for exercising your brain in ways that will support its continuing good health.
