It goes without saying that exercise improves brain function through a number of factors including stimulating angiogenesis (creation of new blood vessels), neurogenesis (creating of new neurons), synaptogensis (creating new synapses), and production of brain growth factors called neutrophins. One of the hallmark neutrophins that has been well studied is called Brain Derived Neutrophic Factor (BDNF).
BDNF is a protein that has been touted as “Miracle-Gro For The Brain” by Harvard Psychiatrist John J Ratey, MD. BDNF is known to not only stimulate the growth and differentiation of new neurons but has also been shown to support and preserve the survival of existing neurons and neuronal pathways. According to Dr Brant Cortright, an expert in neurogenesis, 60–70% of new neurons that are formed via neurogenesis get removed before they can become integrated into our neural network. BDNF plays a major role in helping preserve these newly forming neurons.
One study also showed BDNF can even help turn white fat into metabolically enhancing brown fat . Just another reason to live The Neuro Lifestyle: you can also burn fat at the same time.
Much study and research is being dedicated to discovering methods that help promote neurogenesis and production of BDNF to not just stimulate growth of new neurons or brain cells but to also preserve them. At the forefront of the debate has been exercise and in particular, which type of exercise is best at promoting brain health.
Any type of exercise is beneficial in its own right, but certain types of exercise can help the brain become more resilient, adaptable, and powerful through the benefits listed above. This can also lead to
- Increased memory
- Increased cognition
- Increased learning abilities
- Less depression
- Less anxiety
- Better resiliency to stress in all forms.
EXERCISE AND YOUR BRAIN
A hallmark Harvard study done on rats showed that aerobic exercise had the most profound effect of neurogenesis and production of BDNF compared to high intensity training and resistance training. Aerobic exercise would include lower to moderate level intensity exercises like running, rowing, walking, and biking. The study reported that the more miles the rats ran, the greater levels of BDNF were produced. It seemed that high intensity training (HIIT) did not have the same effect in this study, and the lead authors speculated that HIIT may be “too physiologically draining on the body.” 
On the other hand, multiple studies have demonstrated the profound BDNF promoting effects of HIIT. [3, 4] The key, according to Dr Ratey, is to do as much as possible in the quickest amount of time. One particular study also showed a 20% improvement in learning ability!  Who doesn’t want that? On top of increased BDNF, there was also an increase in catecholamines, dopamine, epinephrine, and norepinephrine.
In both cases resistance training did not show considerable elevation of BDNF. Bicep curls make your arms look good, but the data shows that unfortunately they don’t do much for your brain. Now does that mean you shouldn’t do any resistance training? No! Resistance training has many benefits for your overall health and should be included whether in your HIIT training or as a stand alone workout.
SO WHAT SHOULD YOU DO?
It would seem from the research that a well-rounded exercise routine that is predominately a combination of HIIT and aerobic training is best suited for a neuro-enhancing lifestyle. If you are a runner, try adding in some HIIT (Sprinting, Crossfit, Tabata, Orange Theory) a few days a week and see what you notice. If you are someone who only does HIIT, you may find that including some aerobic exercise can help boost your recovery and increase your work capacity.
I’ve personally noticed that incorporating several days a week of moderate distance running (2–4 miles, 2–4 times per week) has helped my recovery but also had some incredible brain boosting effects. Many runners mention increased creativity and ideas during a long run, which likely is from the increased neurogenesis and BDNF boost! I’ve also noticed consistently better heart rate variability (HRV) scores since adding in a few aerobic workouts in place of my HIIT workouts.
This type of research confirms why and how exercise is so valuable for our mental health. Depression, anxiety, memory loss, and focus challenges are escalating at an alarming rate. Low levels of BDNF have been linked to depression . While there are many factors involved in each of these challenges, studies have shown how effective exercise is at enhancing our mental wellbeing. One study showed just 30 minutes of treadmill walking per day was enough to produce a statistically significant reduction in depression symptoms.
PLEASE NOTE: This does not mean these are the only areas of fitness to work on. Resistance training, mobility, balance, and other aspects of fitness are important as well, so make sure to incorporate those into a wholistic movement routine.
ADDITIONAL METHODS TO INCREASE YOUR BDNF
1. Sunshine — Vitamin D
Vitamin D has been shown to increase BDNF levels. Considering that depression is on the rise and a majority of the world is deficient in vitamin D, it couldn’t hurt to get a little sunshine in your day, and maybe get a tan while your at it. If you live in an area that doesn’t get a lot of sunshine it’s well worth getting a quality vitamin D supplement or investing in a quality sun lamp.
Top supplements for increasing BDNF include Magnesium-L-Threonate, Ashwagandha, Resveratrol, Cocao Flavanoids from Chocolate (not Hershey’s Chocolate), Milk Thistle, Green Tea, Krill Oil, and Magnolol. DHA, found in fish oil and krill oil has been well studied and shown to have significant improvement on BDNF levels.  There several more options out there but these are just some of our favorites. We recommend trying them out and seeing which one works best for you.
3. Avoid Inflammatory Foods
It goes without saying that inflammation produced from neuro toxic food will decrease neurogenesis and production of BDNF. Sugar, high carbohydrate diet, unhealthy fats like trans-fat, fried foods, refined grains, conventional meats, alcohol, and diary have all been shown to increase chronic inflammation in the body, which in turn decreases neurogenesis and BDNF levels. Eat to fuel your brain not drain it!
4. Enrich Your Environment
According to Dr Brant Cortright, PhD, author of The Neurogenesis Diet and Lifestyle, enriched and stimulating lifestyles and social environments lead to increased neutrophic activity and BDNF while decreasing stress and anxiety. The brain thrives on just the right balance of new stimulation (reading, writing, new activities, social interaction, travel, etc) and familiar stimulation. Enriched social lives have been shown to increase BDNF levels.
5. Intermittent Fasting
It’s been shown that caloric restriction through fasting, whether long durations or intermittently (12–14 hours) have been shown to increase BDNF levels and stimulate neurogenesis. It also is worth mentioning that overeating can decrease neutrophic activity. There are many other profound benefits with intermittent fasting beyond just it’s benefits on brain health and potential as well. 
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