Do you exercise, and if so, does it benefit you? Most of us exercise because we know it is good for our physical health. The opportunity for fun with friends and social interaction is enjoyable too. Would you also agree that exercise makes you feel more invigorated and positive? It’s a great way of lifting those occasional sombre moods and ‘re-booting’ your brain. But is there any solid ‘scientific’ explanation for how and why exercise apparently boosts brainpower?

Yes. Empirical research shows exactly how exercise works not only to tone your mid-section, but also your mind! Your brain is no different to your muscles in the respect that--you either use it or you lose it!

As John Ratey (ref. 1) Harvard Medical School psychiatrist and author of “Spark: The Revolutionary New Science of Exercise and The Brain,” says, “Exercise is the single best thing you can do for your brain in terms of mood, memory and learning.”

How exactly does Exercise Re-Boot Your Brain?

Physical exercise has positive effects on brain function in many ways ranging from the cellular to the behavioural. For example, exercise has been shown to:

1. Increase the heart rate, pumping more oxygen rich blood to the brain, and, thereby improving memory formation in healthy young adults, as well as improving reaction time Better yet, the physical activity doesn’t have to be gruelling to increase blood flow. Mild activity like a leisurely walk may help to increase blood flow, fend off memory loss and keep skills like vocabulary retrieval strong.
2. Aid the release of several hormones, including growth factors, all of which help to provide a nourishing environment for the growth of brain cells. This in turn boosts our learning capacity. Research from UCLA  demonstrated that exercise increased growth factors in the brain - making it easier for the brain to increase plasticity and grow new neuronal connections.
3. Encourage the same antidepressant-like effects associated with "runner's high". A Stockholm study  showed that the antidepressant effect of running was also associated with more cell growth in the hippocampus, an area of the brain responsible for learning and memory.
4. Increase levels of serotonin, dopamine and norepinephrine, three brain-soothing chemicals which ease tension and stress. Researchers from the UCSF claim this benefit happens with only 30 minutes of jumping on a treadmill or cross trainer.
5. Further, according to the same study , not only will exercise reduce stress, it may reverse the toll stress takes on the aging process by intervening on a cellular level. After stressed-out study participants exercised an average of 45 minutes a day over a three-day period, their cells showed fewer signs of aging than inactive study participants’ cells.

In a nutshell, working out keeps you younger!

Different Exercise Styles = Different Brain Benefits

Interestingly, several studies show how differences between exercise styles, such as cycling versus walking have different brain benefits. For example, one study (ref. 6) showed how ballroom dancing has a greater benefit on cognitive functioning, especially in protecting against age-related cognitive decline, than exercise or mental tasks alone.

This indicates that the best brain health workouts may involve those integrating different parts of the brain such as coordination, rhythm, and strategy. Ballroom dancing involves all these as well as physical demands as dancers must carefully coordinate and synchronise with their partner.

A meta-analysis on the effects of exercise on cognitive function in older adults concluded that:

• exercise programs involving both aerobic exercise and strength training produced better results on cognitive abilities than either one alone
• more than 30 minutes of exercise per session produces the greatest benefit

All these examples illustrate the brain boosting benefits of exercise, but they don’t really explain the underlying biological mechanism behind WHY exercise has positive benefits on boosting brain power, and especially memory ability.

Do you have any idea?

I didn’t until I unearthed a pivotal Irish study.

The Key Biological Reason Why Exercise Boosts Brainpower

The Irish study is significant because it clearly showed how and why exercised volunteers performed significantly better on memory tests than the volunteers who had rested and did not improve.

Using blood samples before and after exercise, and samples from the non-exercisers, the researchers noted that immediately after the strenuous activity, the cyclists had significantly higher levels of a protein known as brain-derived neurotrophic factor, or BDNF. This is known to promote the health of nerve cells . The men who had sat quietly showed no comparable change in BDNF levels.

For some time, scientists have believed that BDNF helps explain why mental functioning appears to improve with exercise. However, they haven’t fully understood which parts of the brain are affected or how those effects influence thinking.

The Irish study, as well as other research, suggests that the increases in BDNF prompted by exercise may play a particular role in improving memory, recall and possibly other brain functions.

Perhaps the most revealing of the recent experiments is one involving aging human pilots (ref. 11). For the experiment, scientists at Stanford University School of Medicine asked 144 experienced pilots ages 40 to 65 to operate a cockpit simulator three separate times over the course of two years.

For all of the pilots, performance declined somewhat as the years passed. A similar decline with age is common in all of us.

But in this case, the decline was especially striking among one particular group of men. These aging pilots carried a common genetic variation that is believed to reduce BDNF activity in their brains. The men with a genetic tendency toward lower BDNF levels seemed to lose their ability to perform complicated tasks at almost double the rate of the men without the variation.

While the pilot experiment wasn’t an exercise study, it raises the question of whether strenuous exercise could slow such declines by raising BDNF levels, thereby salvaging our ability to perform skilled manual tasks well past middle age.

One of the researchers Dr Salehi says: “So many studies have shown that exercise increases levels of BDNF. Other growth factors and body chemicals are “upregulated” by exercise, but BDNF holds the most promise. The one factor that shows the fastest, most consistent and greatest response is BDNF,” he says. “It seems to be key to maintaining not just memory but skilled task performance.”

In other words, appreciating how BDNF works, helps us understand how exercise positively affects the brain in so many ways.

Is Too Much Exercise Bad for the Brain?

As with too much of anything, excess exercise may have negative effects on the body and brain. Not only does it appear to reduce BDNF levels, it also shrinks the brain!

Studies (ref. 12) show how extreme sports such as ultramarathons, may lead to “a volume reduction of about 6% “. Compare that with ‘normal’ physiological brain volume reduction during aging of less than 0.2% per year. Fortunately, it appears that the shrinkage is reversible in time, as long as the excess exercise does not continue.

Exercise responsibly!