Mike Israetel

Because at Mach 3, what's happening to the plane is just running through subsequent brick walls. That's what the sound barrier is like. Three times faster than the sound barrier, you're just rattling that thing into dust. That's what you're trying to do to it.

When you're pushing your body really hard and the weights are slowing down and there's sets of 5 or sets of 8 or sets of 10, your body's very close to its limits. So both your faster twitch muscle fibers, which are required, they take way more damage. They're also not as well proliferated with blood supply and they heal slower.

When you're pushing your body really hard and the weights are slowing down and there's sets of 5 or sets of 8 or sets of 10, your body's very close to its limits. So both your faster twitch muscle fibers, which are required, they take way more damage. They're also not as well proliferated with blood supply and they heal slower.

and the amount of absolute force is higher and the amount of neural drive it takes, you can hop on a bike for an hour at zone two every day. And afterwards, people are like, are you tired? And you're like, a little bit. I kind of feel like also a little bit refreshed in a sense. You don't really feel refreshed after like grinding the leg press for five sets of 15.

and the amount of absolute force is higher and the amount of neural drive it takes, you can hop on a bike for an hour at zone two every day. And afterwards, people are like, are you tired? And you're like, a little bit. I kind of feel like also a little bit refreshed in a sense. You don't really feel refreshed after like grinding the leg press for five sets of 15.

You feel like someone beat the crap out of you and you don't owe anyone money. What the hell is going on? So that intensity, that absolute intensity of lifting and high relative intensity, that's what tends to make the big, big fatigue cost.

You feel like someone beat the crap out of you and you don't owe anyone money. What the hell is going on? So that intensity, that absolute intensity of lifting and high relative intensity, that's what tends to make the big, big fatigue cost.

I'm glad you brought up the peripheral. One of the big misconceptions is that there's muscular fatigue, connective tissue, systemic fatigue, blood vessels, and everything still after heart has to pump. But then people just say, oh, and then the central nervous system. Well, the peripheral nervous system is a thing too, and it also takes substantial amount of fatigue.

I'm glad you brought up the peripheral. One of the big misconceptions is that there's muscular fatigue, connective tissue, systemic fatigue, blood vessels, and everything still after heart has to pump. But then people just say, oh, and then the central nervous system. Well, the peripheral nervous system is a thing too, and it also takes substantial amount of fatigue.

So I would just say the nervous system takes fatigue. And it takes fatigue in the same way you would expect any system that's pushed to its limits to take. various components of it experience wear and tear, various substrates deplete and need to be repleted. So I can bring up two examples.

So I would just say the nervous system takes fatigue. And it takes fatigue in the same way you would expect any system that's pushed to its limits to take. various components of it experience wear and tear, various substrates deplete and need to be repleted. So I can bring up two examples.

In the axon of any single given nerve, you have a balance of electrolytes inside and outside, which allows the proliferation of the electrical signal. You run that system long and hard enough, and it starts to get out of whack to where you try to get another impulse going, and it's like, ugh. So it needs to do a lot of pumping,

In the axon of any single given nerve, you have a balance of electrolytes inside and outside, which allows the proliferation of the electrical signal. You run that system long and hard enough, and it starts to get out of whack to where you try to get another impulse going, and it's like, ugh. So it needs to do a lot of pumping,

to take what's supposed to be inside the cell that's now outside the cell to get back in there to a level of concentration that would be fully recovered. Now, typically that happens quickly, but if you run that system a lot, there are various points at which some of the structures that are supposed to do that, they're also proteins.

to take what's supposed to be inside the cell that's now outside the cell to get back in there to a level of concentration that would be fully recovered. Now, typically that happens quickly, but if you run that system a lot, there are various points at which some of the structures that are supposed to do that, they're also proteins.

you use them enough and they start to kind of break a little bit and you need to produce more proteins to replace the channels themselves that do that pumping back and forth. And so that typically protein construction is measured on the order of minutes, hours, and days, not seconds. So that you could imagine it as like a transatlantic cable.

you use them enough and they start to kind of break a little bit and you need to produce more proteins to replace the channels themselves that do that pumping back and forth. And so that typically protein construction is measured on the order of minutes, hours, and days, not seconds. So that you could imagine it as like a transatlantic cable.

You throw enough current through a cable and the fish nibble at the cable enough, you need to start replacing the cable. Now, if you're really, really using the crap out of that cable, yeah, it's going to like undergo some not so great things. And then closer to neuron to neuron junctions or the neuromuscular junction between the neuron and the muscle itself,

You throw enough current through a cable and the fish nibble at the cable enough, you need to start replacing the cable. Now, if you're really, really using the crap out of that cable, yeah, it's going to like undergo some not so great things. And then closer to neuron to neuron junctions or the neuromuscular junction between the neuron and the muscle itself,

You have vesicles of neurotransmitter. You pump enough of those in, you get the cool stuff of communication. You can run low on neurotransmitter. And then like the electrical signal arrives and neurotransmitter is like, sorry, not enough of us to do anything. And so you experience fatigue expressed as weakness.