Scientific American has a fascinating article that explains why you should exercise your brain while you exercise your body (January 2020;322(1):26-31). Almost 50 percent of North Americans over 85 and 13 percent of those over 65 suffer from loss of brain function called dementia (Alzheimer’s Assoc Facts and Figures, 2018). We know that you lose brain cells as you age, and scientists used to think that you could not make new brain cells. However, aging causes memory loss by reducing blood flow and nourishment to brain cells (Neurology, December 05, 2017; 89 (23). You may be able to improve some aspects of brain function with aging by exercising (Nat Rev Neurosci, 2008 Jan;9(1):58-65) and there is evidence that you may be able to make You can make new brain cells as you age by exercising your skeletal muscles and brain at the same time (Cell Stem Cell, April 5, 2018;22(4):589-599).
Several studies show that exercise increases blood flow to the brain to improve mental function in older people with mild cognitive impairment (MCI) that often precedes dementia (Journal of Alzheimer’s Disease, Feb 1, 2019;67(2):671-684). Furthermore, exercise can improve thinking skills in people of all ages (Neurology, January 30, 2019). A regular exercise program and higher level of fitness help to preserve the size of an animal’s brain (Brain Imaging and Behavior, published online June 17, 2019) by causing the body to produce increased amounts of a hormone called BDNF (Eur J Neurosci, Nov 2004;20(10):2580-90). The same improvements in brain function with aging were reported with exercise increasing levels of BDNF in humans (Curr Op in Behav Sci, 2015, 4:27-32).
Our Ancestors Improved Brain Function by Using Their Brains During Exercise
Researchers David Raichlen and Gene Alexander explain why your ancestors may have given you the ability to improve brain function by performing memory tasks while you exercise (Trends Neurosci, July 2017;40(7):408-421; May 2014;37(5):247-255). More than six million years ago, our ancestors split from other primates such as chimpanzees and bonobos by going from moving on all four extremities to walking upright on their hind legs, and going from primarily sitting around eating fruit to a hunter-gatherer life of actively walking and running, chasing animals and searching for edible plants over many miles a day. This forced the brains of hunter-gatherers to work much harder to:
• balance their bodies on two limbs instead of four
• exercise far more to chase and catch animals
• recognize and memorize new surroundings
• use their eyes and ears to find elusive animals
• work out ways to use teamwork to find and capture wild animals
• develop tools and hunting strategies to outsmart their fast-moving prey
Then about 10,000 years ago, our ancestors developed agriculture which meant that they needed less physical energy to find enough food to survive, and could use their more highly-developed brains to figure out ways to feed large communities, where every member did not need to spend all of his or her time looking for food. It is less physically taxing to farm land than to chase wild animals, and now we use our muscles even less. We ride cars instead of walking, we have abundant food available while barely moving to get it and we can watch television without having to think for many hours each day. Researchers believe that within the next 10 years, 50 percent of North Americans adults will be morbidly obese, which means that their excess weight will make them sick and increase their risk for cancers, heart attacks and premature death (N Engl J Med, Dec 19, 2019;381:2440-2450). Our sedentary lifestyles have made us fatter and at the same time, the incidence of dementia is increasing.
Both Physical Exercise and Problem-Solving Help Your Brain
Animals who had to use their brains thinking about earning rewards during exercise preserved their brain cells more than if they just exercised without distraction (Front Neurosci, Nov 10, 2009;3:50). In human studies, people who suffered from Mild Cognitive Impairment (MCI), which usually precedes dementia, had improvement in memory and complicated tasks requiring memory when they exercised while playing a mentally demanding video game (J Clin Med, Sept 2018;7(9):249). The authors of this study have shown that exercising while playing video games increases blood levels of the hormone BDNF, which helps to grow new brain cells, more than just exercising without mental tasks (Am j Prev Med, Feb 2012;42(2):109-19).
Try Using Mnemonics While You Exercise
Mnemonics are learning techniques that help you to remember or retrieve information that you have studied. For example, it is far easier to remember the words in a song than in a poem because your brain is helped by the association of words with music. Think of all the lists and memory tricks you have learned in your lifetime, such as:
• Thirty days hath September, April, June and November, all the rest have 31 except February . . .
• Spring forward, fall back: to set your clock at standard and daylight time changes
• Righty-tighty, Lefty-loosey: to turn a nut on a bolt or a handle on a spigot
• Every Good Boy Does Fine: the lines of a treble music bar, and FACE: the spaces of a treble music bar
• Never Eat Sour Watermelon: directions on a compass
• I before E except after C: how to use “ie” and “ei” to spell correctly
• My Very Educated Mother Just Served Us Nine Pizzas: the order of the planets in distance from the sun (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune + Pluto)
• HOMES: names of each of the Great Lakes (Huron, Ontario, Michigan, Erie, Superior)
If you have worked in a scientific or technical field you have probably learned mnemonics that only your peers would understand. As you age, you can use this store of knowledge to challenge your brain and to invent new mnemonic devices for yourself. Try to do these during physical exercise:
• Plan what you are going to do the rest of the day and then compose a mnemonic that puts your tasks in proper order
• Make a grocery list, and create a mnemonic for that list
• Do math problems in your head
• Try to memorize a few words in a foreign language just before you exercise, make up a mnemonic for these 5 to 10 words, and repeat the mnemonic and its meaning many times while you exercise
• Learn the words of a new song just before you exercise and repeat that song as you exercise
• Learn to do a new kind of exercise that requires you to concentrate on developing skills and coordination in new ways — such as line dancing or water aerobics.
Loss of brain function is a frightening result of aging. Your brain is like your skeletal muscles: you have to use them both to keep them. Exercising your muscles causes cells to produce BDNF, a hormone that can cause new brain cells to grow, so you may be able to help retain your memory even better by exercising your brain and skeletal muscles at the same time.
Try to work up to being able to exercise for 30 minutes every day while using your brain — either to pay attention during a challenging exercise activity (such as riding a bicycle outdoors), or by playing mind games, solving problems and practicing new mnemonics related to your current activities and interests.
Why Your Brain Needs Exercise, Scientific American, January 2020