Jeff Krasno

And that's totally normal. And that's good. Your heart rate and respiratory rate decrease. Your aperture opens back up. You become more trustworthy of the world around you. And that's great. That's adaptive. But I think in this culture... the rattlesnake almost never leaves the path. So we're constantly and chronically stressed.

And that's totally normal. And that's good. Your heart rate and respiratory rate decrease. Your aperture opens back up. You become more trustworthy of the world around you. And that's great. That's adaptive. But I think in this culture... the rattlesnake almost never leaves the path. So we're constantly and chronically stressed.

And that's totally normal. And that's good. Your heart rate and respiratory rate decrease. Your aperture opens back up. You become more trustworthy of the world around you. And that's great. That's adaptive. But I think in this culture... the rattlesnake almost never leaves the path. So we're constantly and chronically stressed.

And that's really the difference between how we experience bad, chronic, modern stress and what I would call sort of paleolithic good stress. And if you begin to actually look at the nature of stress, there are so many mechanisms in the human body that are adaptive.

And that's really the difference between how we experience bad, chronic, modern stress and what I would call sort of paleolithic good stress. And if you begin to actually look at the nature of stress, there are so many mechanisms in the human body that are adaptive.

And that's really the difference between how we experience bad, chronic, modern stress and what I would call sort of paleolithic good stress. And if you begin to actually look at the nature of stress, there are so many mechanisms in the human body that are adaptive.

I mean, if you were to go, let's say, to a high altitude, or if we were just to sit here and to, like, hold our breath for a while, might not be really great for the podcast, but... But over time, let's say if we held our breath for a minute, we would have sort of a glut of carbon dioxide. So that's called like hypercapnia and a dearth of oxygen. That's called hypoxia, right?

I mean, if you were to go, let's say, to a high altitude, or if we were just to sit here and to, like, hold our breath for a while, might not be really great for the podcast, but... But over time, let's say if we held our breath for a minute, we would have sort of a glut of carbon dioxide. So that's called like hypercapnia and a dearth of oxygen. That's called hypoxia, right?

I mean, if you were to go, let's say, to a high altitude, or if we were just to sit here and to, like, hold our breath for a while, might not be really great for the podcast, but... But over time, let's say if we held our breath for a minute, we would have sort of a glut of carbon dioxide. So that's called like hypercapnia and a dearth of oxygen. That's called hypoxia, right?

Now, too much hypoxia, and the podcast would meet an untimely end. Because too much hypoxia, your brain is not going to get enough oxygen, and you'll sign off one last time here on Know Thyself. But the right amount of hypoxia actually triggers this unbelievable adaptive response in the human body. So you have like these little chemoreceptors right here on the side of your carotid arteries.

Now, too much hypoxia, and the podcast would meet an untimely end. Because too much hypoxia, your brain is not going to get enough oxygen, and you'll sign off one last time here on Know Thyself. But the right amount of hypoxia actually triggers this unbelievable adaptive response in the human body. So you have like these little chemoreceptors right here on the side of your carotid arteries.

Now, too much hypoxia, and the podcast would meet an untimely end. Because too much hypoxia, your brain is not going to get enough oxygen, and you'll sign off one last time here on Know Thyself. But the right amount of hypoxia actually triggers this unbelievable adaptive response in the human body. So you have like these little chemoreceptors right here on the side of your carotid arteries.

And they say, oh my God, Andre's got a buildup of carbon dioxide. What are we going to do? Hey, make some more red blood cells down there because we need additional couriers. Stop doing that. We need additional couriers for oxygen because oxygen then gets shuttled to our cells and our mitochondria for energy production.

And they say, oh my God, Andre's got a buildup of carbon dioxide. What are we going to do? Hey, make some more red blood cells down there because we need additional couriers. Stop doing that. We need additional couriers for oxygen because oxygen then gets shuttled to our cells and our mitochondria for energy production.

And they say, oh my God, Andre's got a buildup of carbon dioxide. What are we going to do? Hey, make some more red blood cells down there because we need additional couriers. Stop doing that. We need additional couriers for oxygen because oxygen then gets shuttled to our cells and our mitochondria for energy production.

Our mitochondria then becomes hyper-efficient at making energy in hypoxic situations. Also brilliantly, carbon dioxide mitigates body pH balance. So your body's going to get a tiny bit more acidic if you hold your breath for a couple minutes. And that's totally adaptive because In that acidity, hemoglobin sort of loses its affinity for oxygen.

Our mitochondria then becomes hyper-efficient at making energy in hypoxic situations. Also brilliantly, carbon dioxide mitigates body pH balance. So your body's going to get a tiny bit more acidic if you hold your breath for a couple minutes. And that's totally adaptive because In that acidity, hemoglobin sort of loses its affinity for oxygen.

Our mitochondria then becomes hyper-efficient at making energy in hypoxic situations. Also brilliantly, carbon dioxide mitigates body pH balance. So your body's going to get a tiny bit more acidic if you hold your breath for a couple minutes. And that's totally adaptive because In that acidity, hemoglobin sort of loses its affinity for oxygen.

So hemoglobin is that little protein in the red blood cells that takes the oxygen and goes, okay, here we're going off to the blood cells. And if it's more likely to release it, that's better for energy production. So this is just like one of hundreds and hundreds of sort of pre-programmed adaptive responses to stress that exist in the human body.

So hemoglobin is that little protein in the red blood cells that takes the oxygen and goes, okay, here we're going off to the blood cells. And if it's more likely to release it, that's better for energy production. So this is just like one of hundreds and hundreds of sort of pre-programmed adaptive responses to stress that exist in the human body.