The active group was then told to do 50 leg extensions at personal maximum effort using a resistance exercise machine. The passive participants were asked to let the machine move their leg, without exerting any personal effort. Two days later the participants returned to the lab, where they were shown the 90 original photos plus 90 new ones.
Interestingly, those in the active group had markedly improved image recall even though two days had passed since the exercise. The passive control group recalled about 50 percent of the original photos, whereas the active group remembered about 60 percent. Project leader Lisa Weinberg commented on the results saying,13 “Our study indicates that people don’t have to dedicate large amounts of time to give their brain a boost.”
Other research published in 2016 also found a link between exercise and improved long-term memory retention. Here they found that exercising four hours after learning something new helps you retain what you’ve just learned long-term. Curiously, this effect was not found when the exercise was done immediately after learning.14,15
Why this four-hour delay boosted memory retention is still unclear, but it appears to have something to do with the release of catecholamines, naturally occurring chemicals in your body known to improve memory consolidation. These include dopamine and norepinephrine. One way to boost these catecholamines is through exercise, and delayed exercise appears to be part of the equation.16
|Animal research17 has also shown that exercise both activates and promotes the growth of hippocampal neurons. The hippocampus belongs to the ancient part of your brain known as the limbic system, and plays an important role in the consolidation of information from your short-term memory to your long-term memory, as well as spatial navigation.
In one such study,18 exercising mice grew an average of 6,000 new hippocampal brain cells in every cubic millimeter of tissue sampled. As expected, the mice also showed significant improvements in the memory recall. Similarly, a 2010 study19 on primates revealed exercise helped the monkeys learn new tasks twice as quickly as nonexercising monkeys.
|A number of other studies have also investigated the impact of exercise on brain performance and IQ in students and employees
Research highlights20 include the finding that 40 minutes of daily exercise increased IQ by an average of nearly 4 points among elementary school students; among sixth-graders, the fittest students scored 30 percent higher than average students, and the less fit students scored 20 percent lower; among older students, those who play vigorous sports have a 20 percent improvement in math, science, English and social studies; students who exercised before class improved test scores 17 percent, and those who worked out for 40 minutes improved an entire letter grade.
Employees who exercise regularly are also 15 percent more efficient than those who do not, which means a fit employee needs to work only 42.5 hours in a week to do the same work as an average employee does in 50.
The Many Mechanisms by Which Exercise Boosts Brain Health
I’ve already discussed how BDNF links muscle strength and brain rejuvenation, but exercise also influences a number of other biochemical pathways that end up affecting your cognitive function and health, including the following:
|Normalizing insulin and preventing insulin resistance — Exercise is one of the most effective ways to normalize your insulin level and lower your risk of insulin resistance.
This not only lowers your risk for diabetes but also helps protect your cognitive health, as diabetes is linked to a 65 percent increased risk of developing Alzheimer’s.21 Insulin actually plays an important role in brain signaling, and when proper signaling of insulin in the brain is disrupted, dementia follows.22
|Improving blood flow and oxygenation to your brain — Your brain needs a significant supply of oxygen to function properly, which helps explain why what is good for your heart and cardiovascular system is also good for your brain. The increased blood flow that results from exercise allows your brain to almost immediately function better. As a result, you tend to feel more focused after a workout, which can improve your productivity.|
|Reducing plaque formation — In one animal study,23 significantly fewer damaging plaques and fewer bits of beta-amyloid peptides, associated with Alzheimer’s, were found in mice that exercised, and by altering the way damaging proteins reside inside your brain, exercise may help slow neurodegeneration.|
|Decreasing bone morphogenetic protein (BMP) — BMP slows down the creation of new neurons, thereby reducing neurogenesis. If you have high levels of BMP, your brain gets increasingly sluggish. Exercise reduces the impact of BMP, thereby allowing adult stem cells to perform their vital functions of keeping your brain agile. In animal research, mice with access to running wheels reduced the BMP in their brains by half in a single week.24|
|Boosting noggin — Exercise also results in a notable increase in another brain protein called noggin, a BMP antagonist. So, exercise not only reduces the detrimental effects of BMP, it simultaneously boosts the more beneficial noggin as well. This complex interplay between BMP and noggin appears to be a powerful factor that helps ensure the proliferation and youthfulness of neurons.|
|Lowering inflammation — Exercise lowers your levels of inflammatory cytokines associated with chronic inflammation and obesity, both of which can adversely impact your brain function.25|
|Increasing mood-boosting neurotransmitters — Exercise also boosts natural feel good hormones and neurotransmitters associated with mood control, including endorphins, serotonin, dopamine, glutamate and GABA.
A study by Princeton University revealed exercising creates excitable neurons along with new neurons designed to release the GABA neurotransmitter, which inhibits excessive neuronal firing, helping to induce a natural state of calm.26 The mood-boosting benefits of exercise occur both immediately after a workout and continue on in the long term when done regularly.
|Metabolizing stress chemicals — Researchers have also teased out the mechanism by which exercise helps reduce stress and related depression — both of which are risk factors for dementia and Alzheimer’s disease. Well-trained muscles have higher levels of an enzyme that helps metabolize a stress chemical called kynurenine. The finding suggests that exercising your muscles helps rid your body of harmful stress chemicals.27|
Daily Walking and a Four-Minute Daily Workout — A Winning Combo Most People Can Do
There’s little doubt that — aside from poor diet — inactivity is a major driver of most of our current disease epidemics, starting with obesity, which now affects nearly 40 percent of adults, over 18 percent of teens and nearly 14 percent of children. In addition to a wide array of health problems, obesity is also a risk factor for Alzheimer’s, which is now the third leading cause of death, right behind heart disease and cancer.