Is medium-high intensity training better than low intensity training, or even crossword puzzles, for your brain health?

A very comprehensive study published in 2015 by the journal Neurology shows a follow-up of a group of elderly adults (around 700), born in 1936, in Scotland.  By 1947, nearly all of them had been given mandatory intelligence and mental health tests at school.

This gave the researchers a baseline to work from, and decades later, the researchers performed MRI scans on the participants at age 70 to document their brain size.

They were then followed up on activities such as crossword puzzles and chess, as well as daily physical activities such as housework and walking. Three years later they had MRI scans again to measure how much their brains had shrunk.

It turned out there was a "strong and direct correlation showing that as physical exercise increases, brain shrinkage decreases," says Christopher Wanjek of LiveScience magazine. "Just going for a walk a few times a week seems to be enough."

Furthermore, high-intensity exercise may provide even stronger effects, as we will see shortly.

 

Could medium-high intensity physical exercise prevent Alzheimer's or Parkinson's?

According to Mollie McGurk’s article on BrainFacts.org, “There is growing evidence that moderate to high intensity workouts may be better for keeping us “awake” as we age. ”

Increasing exercise intensity could have an even more profound impact on mechanisms important for forging new connections and repairing potential brain damage.

But be careful! You cannot go from a sedentary lifestyle to doing high-intensity training.  Everything requires adaptation and, above all, taking into account where you come from, that is, what physical condition you are in, whether you have a sports history or have been rather sedentary, whether you have injuries, etc.

 

How High Intensity Exercise Helps Your Brain

According to Mollie McGurk of BrainFacts.org, intense exercise is shown to benefit the brain in specific ways:

• “By increasing heart rate, the brain releases neurotransmitters that improve mood, cognitive function and maintain brain volume.
• Intense exercise also improves blood flow to the brain, which exposes it to better nutrient absorption, cell growth, and prevention of neuronal damage.
• Muscles secrete the hormone irisin into the blood at higher levels during intense exercise. Irisin is linked to the growth and protection of neurons.
• Intense exercise triggers the release of ketones that are produced in the liver in the absence of glucose. The ketone body beta-hydroxybutyrate (BHB) has been shown to improve brain function in patients with vascular dementia by protecting the blood-brain barrier and reducing neuroinflammation.

In fact, the ketone BHB, the hormone irisin, and a key metabolite called lactate—which have all been shown to boost cognitive performance after HIIT (high-intensity interval training)—may be among the messengers that tell the brain to produce a critical protein called brain-derived neurotrophic factor (BDNF). BDNF is known as “brain fertilizer” because it encourages the growth of new neurons and connections.

McGurk mentions in his article a study where just six minutes of high-intensity cycling increased BDNF levels four to five times more than low-intensity cycling. According to the researchers, “performing exercise at high intensity, BDNF has been shown to increase above what would be expected.”

• In addition, high-intensity acute exercise should provide direct benefits to the brain, such as an increase in the thickness of the cerebral cortex, thanks to the strengthening of what is known as the middle anterior cingulate cortex, which we will discuss shortly. This is because there is an improvement in the integrity of the white matter that is responsible for connecting regions that send and receive signals, affecting the ability to concentrate and learn, solve problems and maintain balance when walking. Likewise, it promotes neuroplasticity, that is, the brain's ability to form new neural connections and adaptations throughout life, as indicated by a study published in the journal Frontiers (Frontiers in Psychology) in 2022.

 

The path to solid and lasting mental acuity would be through your heart.

Heart rate is a measure used to define exercise intensity levels. Moderate intensity requires between 50% and 70% of your maximum heart rate (220 - your age = X), and would be like brisk walking or moderately paced biking. High intensity requires between 70% and 85% of your maximum heart rate, such as running or biking at high speeds. This is where the benefits we've mentioned start to unfold.

In the depths of the brain

Science continues to study activities such as athletics, which provide what they call a “runner's high” or that zen-like state produced by endorphins that allows a runner to continue the race even when exhausted; or the practice of yoga, which allows one to enter a state of meditative relaxation while doing it.  Both practices induce profound effects on the brain. Let's now look at what you specifically practice and how they produce effects to keep the brain healthy and functional :

Here is my choice of physical exercises that provide visible effects to your body and concrete benefits to your brain.

I have chosen some activities that provide both tangible benefits for your body and your brain:

1. Cardiovascular endurance training

The part of the brain that is strongly activated by aerobic exercise (vigorous walking, running, swimming, cycling) is called the hippocampus . Because the hippocampus is at the core of the learning and memory systems in the brain, this finding partly explains the increased effects on memory from a trained physical state.

2. Weight training

According to an article at www.aarp.org A 2020 study published in the journal Neuro Image: Clinical found that six months of strength training may help prevent hippocampal shrinkage in older adults. Another study, published in the Archives of Internal Medicine , compared the effects of two different types of exercise performed once or twice a week for 12 months among women ages 65 to 75 — balance and tone training and strength training — and found that lifting weights produced the best results for memory and other measures of cognition .

"When you lift weights, you focus on form and performing specific movements, which in turn exercises the neural circuits in the brain," the study's director explained.

Strength training stimulates direct blood flow to the brain, allowing for greater efficiency in its functioning.  It also increases the production of endorphins, neurotransmitters that stimulate the feeling of well-being, reduce anxiety and enhance cognitive functions.

3. High intensity interval training

High-intensity interval training has been shown to activate what is known as Brain-Derived Neurological Factor or BDNF, a key protein for brain function related to learning and memory.  It involves altering the intensity of a certain exercise or several.  For example, you can walk for two minutes and run for three minutes at a faster speed.

4. Yoga

The physical practice of yoga helps you improve your cognitive processes, concentration and memory.  Conscious postures, movements and transitions during practice improve your cardiovascular function, your relationship with your body and an overall sense of well-being. 

Here I am referring specifically to the practice of the Ashtanga style that involves breath control, physical movement (postures and transitions), meditation and Mindfulness practices.  At the cortical level, studies suggest that yoga may contribute to increased gray matter in the hippocampus and insular cortex. In addition, yoga appears to increase functional connectivity. Finally, yoga examined in other studies appeared to increase molecular compounds associated with positive changes in the parasympathetic nervous system.

5. Dance

Dancing can reduce the risk of dementia by up to 76%.  The idea is that we try to stay standing as long as possible.  A 2018 study published in the journal PLOS ONE found that adults aged 45 to 75 who sat for at least three hours a day had substantial thinning of their medial temporal lobe, a part of the brain responsible for forming new memories. “This thinning is often a precursor to dementia,” explains one of the scientists who conducted the study.

6. Stretching

According to online magazine www.dmoose.com , stretching exercises increase blood flow to muscles and organs, including the brain where it receives a better supply of oxygen and other crucial nutrients.

Stretching helps reduce inflammation and regulate stress hormones, especially at the end of interval, resistance or strength training.  At the brain level, it promotes focus and reduces mental tension. It can even help improve memory due to its prolonged attention effect.

The combination of physical movements involved in stretching can help reorganize brain pathways, creating neural connections that benefit cognitive functions such as learning processes.

 

Don't neglect your mental training

As you exercise your body, do specific workouts for your brain as well. Some research suggests that engaging in mentally stimulating activities helps build cognitive reserve, the ability to withstand adverse brain changes before symptoms appear. Some experts suggest that people who have completed higher education or have been exposed to brain-stimulating activities may be more resistant to the negative effects of brain disease. 

No matter your age, dare to learn a new language, at your own pace, you don't have to prove anything to anyone. It's for you! Or try a musical instrument, or join one of those groups that go on ecological walks or help out at a foundation.

What you can do in your daily life

1. Stay physically active: Aim for at least 150 minutes of moderate-intensity aerobic activity such as walking, jogging, cycling or swimming per week, keeping in mind that ANY physical activity benefits your brain.  And as much as you can, try to incorporate 2-3 intense exercise sessions per week.  Your brain will thank you.

1. Seriously consider improving your sleep quality : Some theories suggest that sleep can help remove abnormal proteins from the brain, which helps consolidate memories, boost memory, and overall brain health. Aim for seven to eight hours of continuous sleep at night, not fragmented sleep of two or three hours. It is during the third hour of deep sleep that the human growth hormone is activated and triggers its important restorative and rejuvenating benefits. Likewise, consecutive sleep gives your brain the time and space to consolidate and store your memories effectively.

 

3. Avoid isolation and stay socially engaged : organize get-togethers with friends and family; join a social organization; or volunteer at a church, hospital, or charity group. In Japan, the long-lived Okinawans call this practice Moai , and they believe that the support of their social group also provides them with solidarity and support in terms of finances, health, and spiritual interests.

 

4. Try to eat a Mediterranean-style diet, which has been shown in studies to promote brain health . This dietary model emphasizes a diet based primarily on plants, fish, healthy fats such as those from olive oil, and some whole grains.

According to Bonner-Jackson, a neuroscientist at the Cleveland Clinic in the United States, “New skills and healthy habits are thought to create more connections between brain cells and brain areas. The more new things we learn, the more connections are made, so that even if some of them die off as a result of brain disease, there are still connections available that allow the brain to remain functional.”

Conclusion

Science is still working to figure out how and why, as well as determining the factors that make physical exercise so beneficial for the brain, and even more so medium-high intensity training. However, everything points to an increase in blood flow to the brain , increases in growth hormones , and a massive expansion of the network of blood vessels in the brain .

We see then that the cognitive benefits are almost as impressive as the physical benefits of exercise on the body. This reminds us that our bodies and our brains do not function in isolation from each other. What you do with your body, what you feed it, can benefit or harm your mental faculties.

Your body and mind are connected, so as long as you stay physically, mentally and socially active and treat your body well (nutrition and restorative rest) you can make a big difference.

Being a sedentary person all day, every day is dangerous for your physical and mental health, so don't wait! Find an activity and do it, or simply go for a walk.