High-intensity exercise that activates the adrenals to release adrenaline can leverage the vagus nerve to link body and brain excitation, thereby increasing alertness.

“Knowing the organization of these neural circuits from the body to the brain, and how they match levels of alertness, and leveraging them is so straightforward, but most people don't actually get to the point where they're doing that high intensity work, or they're doing the work that involves the large musculature of their body when they're feeling unmotivated.”

“These could be things like jumping. These could be things like actual resistance training. This could be running. This information really points to the idea of, of course, after a good warmup, doing more sprinting type activity, more strength type activity, six repetitions or less where you're getting close to failure, this sort of thing, to wake up the brain and body, as opposed to doing long, rhythmic activity that's below the threshold of what would activate a lot of adrenaline from the adrenals.”

“So, the idea is to get those adrenals to release adrenaline into your system. It won't cross the blood-brain barrier, but your vagus nerve provides this beautiful link between the body and brain to match levels of excitation from the body to the brain, and you can leverage that.”

“However, the reason we're talking about this is that it's a beautiful opportunity to, A, explain that the vagus nerve is not just about calming down. It's actually actively used to wake up your brain when your body is active, when the large musculature of your body is active.”