Ben GreenfieldFounder, Ben Greenfield Life

An Exercise Hack For A Better Brain

19 Feb 2026 · 2 min

Watch on YouTube

1:40

In this solo talk, Ben Greenfield explains how high‑intensity exercise can improve brain health by leveraging lactate as a usable fuel for neurons and astrocytes. He clarifies that lactate, often mislabeled as a waste product, can be taken up by the brain directly or reconverted to glucose via the Cori cycle. Greenfield also cites research on pomegranate juice, showing dramatic reductions in oxidized LDL (up to 90%), a rise in the protective enzyme paraoxonase (83%), a 20% drop in systolic blood pressure, and a 130% increase in total antioxidant status. He connects these physiological benefits to exercise, noting that both acute and chronic training raise circulating brain‑derived neurotrophic factor (BDNF). Because lactate crosses the blood‑brain barrier, higher blood lactate from intense workouts amplifies BDNF release, thereby promoting neuroplasticity and cognitive performance. The overall message is that pushing yourself to a moderate “burn” during exercise triggers a cascade—lactate, BDNF, antioxidant improvements—that results in a better brain.

Chapters

We know that lactate can get taken up by the neurons and the astrocytes in your brain and be used as a fuel, right? A lot of people still call lactic acid the metabolic byproduct. I'm so sore I have so much lactic acid. No, lactic acid can be used as a fuel by the brain. It can also be converted via something called the CORI cycle back into glucose to be used by the muscles. But lactate is a fuel, just like ketones or glucose are a fuel that can be used by the brain. Now, that's pretty impressive, especially when you consider the fact that oxidized ldl, the form of cholesterol that actually drive plaque formation, decreased in some cases by up to 90%. There was another enzyme, an enzyme that binds to HDL, right, which actively protects arteries from oxidative damage. That enzyme is called para oxinase, increased by 83%. So that's good. Systolic blood pressure fell by over 20% and total antioxidant status in the blood rose by 130% in the pomegranate juice consuming group. Physical exercise. Both acute bouts of physical exercise and chronic training have both been shown to increase BDNF levels. And interestingly, it turns out that lactate crosses the blood brain barrier, which helps link muscle activity to neuroplasticity. Namely, higher blood lactate levels achieved through higher intensity exercise are associated with greater increases in circulating bdnf. And so when that pathway gets jump started by you exercising hard enough to get a little bit of a burn, the effect of that is a better brain.