How to Use Exercise to Improve Your Brain’s Health, Longevity & Performance

KEYPOINTS

• 01

  Most of exercise's immediate brain benefit comes from arousal

  Huberman's central argument is that the short-term cognitive boost from exercise mostly comes from autonomic arousal: higher epinephrine, norepinephrine and cortisol. Growth factors like BDNF, IGF-1 and irisin matter more over the long term. Because the effect works through arousal, timing exercise relative to learning matters, and so does not overdoing it.

• 02

  Arousal improves memory both before and after you learn something

  Work from Larry Cahill's group and others shows that raising arousal after exposure to information, using the cold pressor test (arm in ice water for 1–3 minutes) or adrenaline injections, improves memory for the information and its details. Exercise produces similar arousal. Studies show benefits whether it's done before, during or after learning, so you can fit it to your schedule as long as the two are reasonably close in time.

• 03

  One HIIT session sharpens executive function, but two can dull it

  A high-intensity session before, or even during, cognitive-flexibility tasks like the Stroop test improves performance, likely through arousal plus increased cerebral blood flow. But after two hard sessions in a day (for example two rounds of 4×4 intervals), cognitive performance drops, and this tracks with reduced cerebral blood flow. Too much arousal leads to a trough that makes learning harder.

• 04

  The brain can drive the adrenals directly through movement circuits

  Peter Strick's lab at the University of Pittsburgh traced three networks of brain areas that connect to the adrenal medulla: cognitive, affective and, most strongly, the motor network. Motor regions controlling the trunk and core are especially well connected. That's one reason Huberman favors compound movements like squats, deadlifts, rows and pull-ups for energy and focus. The slower hypothalamus–pituitary pathway still operates alongside this.

• 05

  Loaded bones release osteocalcin, which supports the hippocampus

  Studies, first in mice at Columbia and later in humans, show that bones under mechanical stress release osteocalcin. It crosses the blood–brain barrier and promotes neuron growth and connections in the hippocampus, possibly (Huberman stresses 'perhaps') including new neurons in the dentate gyrus. Many of exercise's BDNF effects appear to depend on osteocalcin. No one has systematically worked out which exercises release the most, so impact and jumping are a reasonable inference rather than a proven protocol.

• 06

  Lactate is brain fuel and helps protect the blood–brain barrier

  During intense exercise, neurons prefer lactate as fuel, which spares glucose for cognitive work afterward. Lactate also acts on the hypothalamus to suppress appetite after hard efforts. It also triggers VEGF, which strengthens the blood–brain barrier. Huberman points out that this barrier breaks down with age and especially in Alzheimer's disease.

• 07

  Exercising after one bad night of sleep is fine, but don't make it a habit

  After a single night with about two hours less sleep than usual, exercise can offset some of the cognitive effects. Keep the intensity moderate to avoid suppressing the immune system, and be careful with complex movements, since sleep deprivation is strongly linked to injury, pain and slower recovery. Using exercise regularly to make up for lost sleep is a mistake.

• 08

  Doing hard things you don't want to do may keep the brain young

  The anterior mid-cingulate cortex lights up when we push through physical or mental challenges. Stimulating it, as in work by Josef Parvizi at Stanford, makes patients feel an impending challenge they're ready to meet. In 'SuperAgers,' people whose cognition stays sharp into their 80s and 90s, this area holds its volume or even grows. Huberman's inference is to do something safe but unwanted at least once a week.