Is Medium-high Intensity Training Better than Low intensity or Even Crosswords Puzzles for your Brain Health?



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

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

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

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

What's more, higher intensity exercise may deliver even stronger effects,  so, keep reading!

Could be Mid- to High Intensity Physical Exercise Prevent Alzheimer's or Parkinson's?

According to Mollie McGurk's article from, "there is growing evidence that moderate- to high-intensity workouts may be better at keeping us awake as we age".

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

But be warned! You can't go from a sedentary lifestyle to high-intensity training.  Everything requires adaptation and, above all, taking into account where you are coming from, i.e. what fitness level you are in, whether you have a sporting history or whether you have been rather sedentary, whether you have injuries, etc.


How Intensity Exercise Helps Your Brain

According to Mollie McGurk of, intensity exercise should benefit the brain in specific ways:

- "By increasing heart rate, the brain releases neurotransmitters that improve mood, cognitive function and brain volume maintenance.

- 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 improved brain function in patients with vascular dementia by protecting the blood-brain barrier and reducing neuroinflammation.

In fact, BHB ketone, the hormone irisin and a key metabolite called lactate, which have been shown to increase 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 fertiliser" because it encourages the growth of new neurons and connections.

McGurk mentions in her 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 the exercise at high intensity, BDNF has been shown to increase beyond what would be expected".

- Acute high-intensity exercise should also provide direct benefits to the brain, such as increasing the thickness of the cerebral cortex, thanks to the strengthening of what is known as the anterior medial cingulate cortex, which we will talk about shortly.  This is because it produces 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.  It also promotes neuroplasticity, that is, the brain's ability to form new neural connections and adaptations throughout life, as indicated in astudy published in the journal Frontiers in 2022.


The Way to Sound and Enduring 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 cycling at a moderate pace. High intensity requires 70% to 85% of your maximum heart rate, like running or cycling at high speeds. This is where the benefits mentioned above begin to unfold.


Deep in the Brain

Science continues to study activities such as running which provides what they call "runner's high" or that zen-like state produced by endorphins that allows the runner to continue running even when exhausted; or the practice of yoga which allows you to enter a state of meditative relaxation while doing yoga.  Both practices induce profound effects on the brain. Let us now look at which practices specifically and how they influence keeping the brain healthy and functional:


Here is My Choice of Physical Exercises that can Provide Visible effects to Your Body and Concrete Benefits to your Brain

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


  1. Cardiovascular Endurance Training

The part of the brain that is strongly activated by aerobic exercise (brisk 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 trained fitness.


  1. Weight Training

According to an article on a 2020 study published in the journal Neuro Image: Clinical found that six months of strength training can help prevent hippocampal shrinkage in older adults. Another study, published in Archives of Internal Medicine, compared the effects of two different types of exercise performed once or twice a week for 12 months among women aged 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 neural circuits in the brain," the head scientist explained.

Strength exercise stimulates direct blood flow to the brain, which allows it to function more efficiently.  It also increases the production of endorphins, neurotransmitters that stimulate a sense of well-being, reduce anxiety, and enhance cognitive function.


  1. 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 brain function protein related to learning and memory.  It involves altering the intensity of a certain exercise or several exercises.  For example, you can walk for two minutes and run for three minutes at a faster speed.


  1. Yoga

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

Here I refer specifically to Ashtanga style practice which involves breath control, physical movement (postures and transitions), meditation and Mindfulness practices.  At the cortical level, studies suggest that yoga may contribute to an increase in grey 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.


  1. Dance

Dance can reduce the risk of dementia by up to 76%.  The idea is that we try to be on our feet for 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.


  1. Stretching

According to the online journal, stretching exercises increase blood flow to muscles and organs, including the brain, where it delivers a better supply of oxygen and other crucial nutrients.

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

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


Do not Neglect your Mental Workouts

As you give your body a workout, also do specific trainings for your brain.  Some research suggests that engaging in mentally stimulating activities helps build cognitive reserve, the ability to resist adverse brain changes before symptoms appear. Some experts suggest that people with higher levels of education or exposure 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 eco-walks or help out at a foundation.


What You Can Do on a Daily Basis

  1. Be 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 sessions of intense exercise per week.  Your brain will thank you.
  1. Seriously consider improving the quality of your sleep: Some theories suggest that sleep can help clear abnormal proteins from the brain, allowing for memory consolidation, memory enhancement and overall brain health. Aim for seven to eight hours of continuous sleep a night, not fragmented two- or three-hour dreams. It is at the third hour of deep sleep that 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.
  1. Avoid isolation and stay socially engaged: organise meetings with friends and family; join a social organisation, or volunteer at a church, hospital or charity group. In Japan, this practice is called Moai by the people of Okinawa, where they are very long-lived, and according to them, the support of their social group also gives them solidarity and support in terms of finances, health, and spiritual interests. 
  1. Try to eat a Mediterranean-type diet, which has been shown in studies to promote brain health. This dietary pattern emphasises a mainly plant-based diet, 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 US, "new skills and healthy habits are thought to create more connections between brain cells and areas of the brain.  The more new things we learn, the more connections are made, so even if some of them die as a result of brain disease, there are still connections available that allow the brain to remain functional.



Science is still working on figuring out how and why, as well as determining the factors that make physical exercise so beneficial to the brain and even more so mid-high intensity training.  However, all point to increased blood flow in the brain, increases in growth hormones and a massive expansion of the network of blood vessels in the brain.

We note 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 nourish it with, can benefit or harm your mental faculties.

Your body and mind are connected, so to the extent that you stay physically, mentally, and socially active and treat your body well (nourishment and restorative rest) you can make a big difference.

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



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