How to Build Endurance in Your Brain & Body

KEYPOINTS

• 01

  Quitting is decided by neurons, not by a '90% mental' split

  Huberman cites a Cell paper in which subjects pushed toward a goal while a virtual environment made their effort look futile. Neurons in the locus coeruleus release epinephrine as an effort signal. Glial cells track that release, and at a threshold they shut it off, which is the moment of quitting. When epinephrine release was extended, subjects kept going. He calls the 'mental versus physical' debate meaningless: endurance is 100% nervous system.

• 02

  Five systems limit endurance: nerves, muscle, blood, heart and lungs

  Neurons need glucose (or ketones if fully keto-adapted) plus sodium, potassium and magnesium, because action potentials and the sodium-potassium pump depend on ATP and the right pH. Muscle burns phosphocreatine and stored glycogen, and its ATP production is temperature-sensitive. Blood carries glucose, fatty acids and oxygen; the heart moves it and the lungs bring in the oxygen. The episode draws heavily on exercise physiologist Dr. Andy Galpin.

• 03

  Muscular endurance: 3–5 sets of 12–100 reps with no major eccentric load

  Muscular endurance fails at the muscle, not the cardiovascular system; push-ups are the classic example. The protocol is 3–5 sets of 12–25 reps (up to 100), resting 30–180 seconds and going to or near failure. Planks or wall sits of 1–2 minutes also work. Avoid slow lowering phases and jumping or deceleration, since eccentric work drives soreness and damage. Push-ups should touch the chest to the floor. Isometrics also build the postural endurance that 'text neck' erodes.

• 04

  Long-duration endurance: one continuous bout of 12+ minutes builds efficiency

  Long-duration work below maximal oxygen uptake builds efficiency of movement and mitochondrial density, so you make more ATP for the same effort and burn less fuel overall. It also builds new capillary beds in muscle; Huberman compares this to swapping a single hose for a sprinkler system. That is why a run that ended at 20 minutes feels easier the next time.

• 05

  Anaerobic HIIT: 3–12 sets pushing above VO2 max

  Work-to-rest ratios run from 3:1 (30 seconds on, 10 off) to 1:5 (20 seconds on, 100 off). The shorter rest suits low-skill movements like assault bikes; the longer rest preserves form with kettlebells or loaded squats, where reps degrade and injury risk rises. Start with about three sets once or twice a week and add a set or two weekly. It improves mitochondrial respiration and the neurons' ability to recruit muscle, which helps with repeated sprints in field and racquet sports.

• 06

  Aerobic HIIT works best at a 1:1 work-to-rest ratio

  An example is running a mile in about seven minutes, resting seven, and repeating for four or more miles of work. Huberman says many people use this to complete half marathons or marathons without having run the full distance in training. It trains nearly all the energy systems at once.

• 07

  Intense intervals strengthen the heart and support the brain

  The extra blood returned to the heart during repeated hard efforts eccentrically loads the left ventricle, increasing stroke volume and lowering resting heart rate. That delivers more glucose and oxygen to muscle and brain, including the hippocampus. Huberman says the brain benefits come through vascularization and factors like IGF-1, not from new neurons. Strength and hypertrophy work has been studied less for the brain and does not produce the same stroke-volume gains.

• 08

  Breathing can be trained as a gear system

  Nasal breathing filters air and is more efficient. Following Brian McKenzie's gear model, do long-duration work through the nose and add mouth breathing as intensity climbs, exhaling on the effort. Galpin's lab found that warming up the intercostals and diaphragm before endurance work lets you breathe more deeply and deliver more oxygen.

• 09

  Hitting 'the wall' can mean over-relying on one fuel

  Briefly speeding up, not to an all-out sprint, can shift muscles toward phosphocreatine or another mix of lipids and carbohydrate. Huberman notes that elite athletes now carb-load and also take exogenous ketones during long races, because the body is built to use multiple fuels at once.

• 10

  Visual focus is a performance tool, which is why pacers are restricted

  Narrowing your gaze to a point activates alertness circuits, including the locus coeruleus, while panoramic vision relaxes you. Run hard to a landmark, then widen your gaze to recover, rather than chaining milestones nonstop, which drains more energy. Visual pacers often invalidate record times, and a runner being passed can suddenly find a 'kick', as with Steve Prefontaine.