Exercise releases "plant food" for your brain

We all know that exercise is good for the body. It keeps our muscles toned and our hearts strong. But why is exercise good for the brain?

When we exercise our neurons release a protein called Brain Derived Neurotrophic Factor (BDNF). The metabolite β-hydroxybutyrate, which increases after prolonged exercise, causes more BDNF to be produced. BDNF helps neurons to sprout new connections (synaptogenesis) and new neurons to be born (neurogenesis). Having more healthy neurons improves memory, makes us sharper overall, and is associated with less risk of neurodegenerative diseases. BDNF is also a potent anti-depressant, which may explain why exercise is so good for improving mood.

What type of exercise releases the most BDNF?

A recent meta-analysis of young healthy adults who had BDNF measured in their blood before and after exercise showed that high intensity exercise raised BDNF levels more than low intensity exercise. High intensity exercises are those which raise heart rate to Zone 4 or higher (145-162 bpm) and include High Intensity Interval Training (HIIT) and sprinting. Perhaps in the future we will have continuous BDNF monitors (CBDNFMs)?

How else could we raise BDNF?

There are clinical trials ongoing to create drugs that target BDNF. It has been challenging to create these therapeutics and various companies are using gene therapy approaches, small molecules, or even synthetic peptides to try and mimic BDNF’s effects.

In some parts of the world people are taking daily IV injections of Cerebrolysin, which is BDNF and other neurotrophins extracted from pig brain, to treat their vascular dementia. There doesn’t appear to be high quality evidence to support this practice and there may be side effects:

"six randomised controlled trials with a total of 597 participants... Five of included studies were conducted in China (three studies), Russia (one study), and Romania (one study), while relevant information of other study was unclear. Where details of funding were available, all studies were supported by the pharmaceutical industry (three studies)... There was a beneficial effect of Cerebrolysin in two studies, but the evidence was very low quality"

Until we have next gen BDNF therapeutics, high intensity exercise is a very beneficial way to feed your neurons.