Neurogenesis, BDNF & Exercise: How Movement Supports Brain Regeneration & Cognitive Health

How you exercise can increase BDNF for greater neurogenesis!

In the previous article we discussed neurogenesis, where it occurs in the brain and the amazing observation that we can stimulate this process through our diet, lifestyle, and behaviors. Before we discuss stimulating neurogenesis with exercise, let’s review some neurogenesis concepts.

What is Neurogenesis?

Neurogenesis is the body’s innate ability to grow new brain cells, new neurons in the adult human brain. Neurogenesis is a type of brain plasticity and plays a part in reducing the degenerative effects that aging has on the brain. The degree to which neurogenesis occurs is dependent on your genetic blueprint and your environmental conditions (state of health and activity). Understanding neurogenesis lays the foundation to explore potential for increasing brain function, health, anti-aging, and reducing cognitive decline.

Neurogenesis occurs in the hippocampus more than any other region in the brain

The hippocampus is a curvy seahorse shaped structure of the brain. It is part of the brain’s limbic system, which is responsible for behavior and emotional responses. Within the limbic system, the hippocampus is responsible for the functions of learning and memory- forming episodic and spatial-navigational memory in particular.

As part of its memory functions, it links to the conscious mind in ways such that senses like smell or taste can evoke a memory from the past. The hippocampus is the primary site of neurogenesis in the brain.

How appropriate that the site of learning in the brain is also the primary site of new brain cell growth!

BDNF stimulates the neurogenic process

Brain Derived Neurotrophic Factor or BDNF for short is a neurotrophin that plays a crucial role in the survival and differentiation of neurons during their development as well as the creation of new neurons. BDNF is found in brain regions such as the hippocampus, amygdala, cerebellum, cerebral cortex as well as organs such as the heart, liver and lungs. The highest concentrations of BDNF are found in the hippocampus.¹ BDNF can be considered as a fertilizer that stimulates neurogenesis. Therefore, factors that stimulate BDNF increase neurogenesis. One of which is exercise.

Exercise increases neurogenesis…. but how

We have known for a long time that exercise improves mood, cognitive function, enhances memory, and learning capability.² It has even been shown to have antidepressant effects and protect against age related cognitive degeneration such as that seen in dementia and Alzheimer’s.³ This is because physical training increases angiogenesis (new vascular formations), synaptogenesis (new neuronal connectivity)^4,5 and hippocampal neurogenesis which improves learning capacity.⁶

Exercise’s effect on neurogenesis occurs because exercised peripheral muscles secrete proteins and other metabolic derivatives into the blood stream. Those materials function as messengers; they cross the blood brain barrier and mediate BDNF function in the hippocampus and other brain regions.⁷

Regular aerobic exercise is best

Exercising to stimulate neurogenesis may be as simple as getting on a mouse wheel. A 2005 study⁸ showed that older age mice placed on a running wheel showed faster acquisition and memory retention in maze tasks after only 1 month of exercise compared to younger non-exercising mice. An even more stunning observation was that the rate of neurogenic decline in aged mice that ran on a wheel for 1 month was reversed by 50%. The same principles apply to us- probably because modern life is a rat race… sorry bad joke.

Humans, similar to mice, have a dose dependent relationship between exercise and BDNF stimulation and expression. Regular aerobic exercise of a moderate nature increases the magnitude of BDNF expression following each workout session.⁹ In fact, Erickson et al. 2011 found that exercise increases the size of the hippocampus in human adults.¹⁰

The greater the regularity of exercise, the higher the consistency of BDNF stimulation and enhanced brain function.

Extreme exercise can disrupt BDNF and Neurogenesis

A 2008 study published in Ageing Research Reviews wrote that extreme exercise has been shown to disrupt and impair metabolic, endocrine and cognitive functions in humans. This is theoretically due to the high production of reactive oxygen species (ROS) that leads to cellular mortality. In other words, exhaustion level training diminishes vitality and with it, neurogenesis.

The article ironically does not define extreme exercise. It does however address acute exercise. All training causes some level of ROS production and release in the body. In regular training, the ROS production is mitigated by free radical scavenging activity following the exercise. This is an adaptive or hormetic response and promotes regular recovery. Acute or irregular training does not involve that same adaptive response.¹¹

Extreme exercise could be interpreted as “regularly training to exhaustion” with triathlons, Iron Man, ultras and other high endurance level type systems. Targeted nutrition for those types of athletes is therefore crucial for replenishing nutrients and mitigating long term impact.

Strength training programs with weights have not shown significant positive BDNF expression.¹² Variations in the number of reps and weight lifted compared to 1 rep max size has been shown to influence the reactive oxygen species (ROS) production. Lifting moderate size weights in a regular training program demonstrates less of an inflammatory response.¹³ In consideration of those findings, weight training remains an integral part of any healthy regimen, for countless health benefits.

Moderate exercise for neurogenesis

Moderate levels of exercise on the other hand have a strengthening effect on the immune system and antioxidant defense system. Moderate aerobic exercise clearly stimulates neurogenesis via BDNF as represented in the current research.⁷ Additionally, regular refers to at least 3 times a week.

High Intensity Interval Training (HIIT) – the best for BDNF

A 2020 study published in the Journal of Clinical Medicine describes an important association between exercise and BDNF production. Lactate is a natural byproduct released by muscle tissue during exercise. Lactate crosses the blood brain barrier and stimulates BDNF activation. Exercises that promote the most lactate production therefore trigger the greatest amount of BDNF activity and neurogenesis.¹⁴

High Intensity Interval Training (HIIT) is currently seen to evoke the greatest response of BDNF activity.^15,16 HIIT is usually performed within sessions of 30 minutes or less. The workload volume is low with moderate short bursts (60 seconds or less) of vigorous exercise at 80% maximal heart rate. The bursts of activity are buffered with intervals of 1 minute or less recovery / recovery level exercise activity. HIIT can be performed using different exercise forms such as cycling, running, swimming and whole-body exercises (calisthenics or weights).

3 BDNF enhancing exercise routines to improve Brain Function

• 30 minutes of cycling, running or swimming at 80% of your maximal heart rate. Keep in mind, as your cardiovascular system acclimates and strengthens, your level of resilience and max efforts will outshine your beginning status. Perform 2-3 times a week for best effect.
• HIIT cycling – following a warmup on the exercise bike perform 7 intervals of 45 seconds pedaling at 90-95% of your maximum heart rate. Intersperse the 45 second intervals with 15 seconds of “rest.” Then perform a cool down session on the exercise bike. Personally, I like to do a 10-minute warmup, the HIIT session and 10-minute cool down on the spin bike. Perform 2-3 times a week for best effect.
• 4x4 Norwegian HIIT workout: Perform 4 minutes of exercise at your maximum intensity with a recovery period of 3 minutes. Perform 4 sets total, thus 4x4. As examples: cycling, jump rope, running in place, running, calisthenic combos etc. Perform 4x4 Norwegian training once a week.

These prescribed routines would be in addition to strength / resistance training as its benefits are extensive.

Neurogenesis food for thought

The hippocampus is responsible for learning and is the primary site of neurogenesis. Regular structured moderate and HIIT exercise stimulates new brain cell production. General learning and especially challenging or novel tasks stimulate new brain pathways.

With that in mind, what double task training would you do? Exercise and a new language? Exercise and self-talk/mental reconditioning? Exercise and overcoming fear? Exercise and rhythm or balance? Even exercise and mental flexibility / laughter?

How would you apply this information to bring greater meaning to your life and your loved ones? 

Disclaimer. The information represented in this article is meant to provide concepts from evidence based research. It is not intended to treat or diagnose any health condition. For appropriate treatment methods please contact your healthcare provider.