In an earlier essay, I described an inverse correlation between chronic inflammation and Brain health. I looked at studies showing how exercise, fasting, sleep, and food alter BDNF levels.

Short for Brain-Derived Neurotrophic Factor, BDNF is a protein that builds new neurons and synapses in the hippocampus, cortex, and forebrain.

Of all the factors I checked, the most profound impact was exercise. Exercise increases BDNF levels by 2–3x compared to resting. And it’s not just about growing new neurons.

BDNF is a key mediator of exercise-induced benefits on the brain. It influences learning and memory, plays a role in neuronal plasticity, and it has antidepressant effects. And you can triple it for free?

I was even more excited to get on my bike and go for a sprint, eager to grow a brain…

Then the fires happened.

I thought about the air and wondered when it would be clean enough to reap benefits from outdoor exercise again. I started reading and found a link between air pollution and inflammation. Thinking back to my old hypothesis, I looked for connection between air quality, exercise and BDNF.

As my hypothesis predicted, there is a relationship. Cycling near a major traffic road negates all the BDNF gains from exercise.

Bummer. Another study showed a 10% decline for cyclists pushing through light air pollution, compared to resting in a clean environment.

Pride cometh before the idiot I felt pride in my inflammation theory and shame at my own stupidity. As a resident of Los Angeles, I was never getting a BDNF boost riding around the city. In the middle of COVID in LA with no gyms, the only brain boost I’ll get will be indoors. But not without filtration…

Nasty air saps your gains We harbor a false sense of purity entering our homes, cloistered from the filthy city. But there’s nothing magically better about indoor air.

You may have less benzine and ozone at home, but you're still breathing smog, pollen, dust, and smoke. Indoor air has 2–5x more VOC’s, or “volatile organic compounds” coming from gas stoves, furniture, drapes, fabrics, hair spray, perfume, etc.

I guess we have to pay for BDNF after all...

Enter the Purifiers Thankfully, an air purifier will sort you right out. Purifiers are made up of three important “stages” that remove different stuff from the air.

Stage 1 is a pre-filter that traps big particles — hair, fibers, and pet dander. You can wash this regularly for strong airflow. Air purifier can do things different than AC, what's the difference? check this blog out - air purifier vs air conditioner.

Carbon filter illustration Stage 2 is a carbon filter that traps gases, like benzine from car exhausts, and formaldehyde from your couch. It works by ad-sorption, where carbon atoms fill up their valence shells by bonding to gases.

After a few months, carbon filters become saturated because the carbon filled its valence shell and can’t form new bonds. Carbon filters require seasonal replacement.

Some HEPA’s are more equal than others The third stage is a True HEPA filter, removing elements down to .3 microns, like pollen, dust, mold, bacteria, dust mites, common smoke, and lead dust. Not a bad start! I have a few mspure home air purifiers that come with 2 years worth of replacement filters. At around $100 each, they’re an absolute bargain, and work very well. Here is a product recommendation, ms18 air purifier can purify most air pollutants in your home, get one for home: