Dr. Patrick: Brain health depends on and is reinforced by periods of high heart rate. Failing that, brain capillary health is compromised, neurons are lost. The shearing forces of fast blood flow, the mechanical stimulation itself exerts distinct biological effects. When these shearing forces reach blood vessels at the blood-brain barrier, they stimulate the production of brain-derived neurotrophic factor, supporting the health of the brain.

Dr. Montagne: We have tiny blood vessels in the brain, so, if you don't exercise, if you don't make sure that your heart is pumping at a high rate regularly during the week, those tiny vessels that are even smaller than your hair in terms of diameter, they will start to collapse.

And you're going to have...and remember, the capillaries, it represents 90% of your brain vasculature, all these tiny blood vessels. So, if you start not...if you don't do enough exercise, you will start chronically to have some vessels that will basically constrict and collapse and disappear. Meaning that the surrounding neurons that are here, they need oxygen and nutrients and everything from these vessels. If these vessels disappear, you're going to lose neurons, right? So, exercise is the number one thing. You have to do that, not only for the brain, obviously, for the heart it's true, for the eyes, obviously.

If you don't exercise, you tend to lose eye vision quicker than a normal person as you age. But very important for the brain, you're going to turn...you know, if you're prone to go to cognitive decline because let's say you have a major genetic risk, but if on top of that, you don't exercise, you're going to accelerate as we know from studies. So, I think exercise right now, it's highly funded, there's a lot of work going on, and that's one of the biggest things we have to put to the world, it's like, "Okay, we need to exercise no matter what." If you want to stay healthy in terms of brain function, yeah, no other choice.