Exercise Creates Structural Stress

Now, the other kind of stress Structural stress from activity that physical activity cause is structural stress. Now, when I was running this morning, for example, my mitochondria were generating all kinds of ATP to fuel my body, but my mitochondria were also spewing out all kinds of reactive oxygen species, which cause widespread damage throughout my body. I was getting mutations in my DNA, those that damage is causing my telomeres at the end of my chromosomes to shorten its damaging cells. It's causing tears in my muscles causing cracks in my bone. And of course, if all that damage were you know, you know, we did nothing about it, right? You know, we'd die soon after exercising, but instead exercise turns on a wide range of repair and maintenance mechanisms that repair all that damage and in fact, increase capacity, so the next time I do a five mile run, I might actually be able to do it with more ease, right? And there are a lot of these, right?

So one of them is, you know, when I produce all those reactive oxygen species, my cells also produce a ton of antioxidants that mop up all that damage. When I stress my mitochondria, my cells are also being induced by exercise to repair and produce more mitochondria that keep my cells healthy. I'm getting DNA damage from all those reactive oxygen species, but I'm turning on all kinds of enzymes that repair DNA. I also turn on factors that repair my brain and actually cause growth of new brain cells. One of them is called brain derived neurotropic growth factor that's turned on by exercise. My muscles when I'm exercising are producing molecules that actually suppress inflammation, keeping my inflammation levels low and my immune system is getting turned on. I produce more natural killer cells and cytotoxic T cells and antibodies, all of which are gonna protect me from infectious diseases. So the bottom line is that when you exercise, you slow rates of aging, you slow the rate at which you lose muscle, you decrease your risk of dementia, you decrease inflammation, you decrease your risk of infectious disease, including by the way covid.

And there's a lot and many, many more kinds of functions like that that improve our health. Exercise is not medicine So the bad news is that exercise really isn't medicine. It's not like a pill that you take like salvarsan or you know, penicillin that you know that that gets rid of a disease. Instead, it's something, it's that instead, it's really the better way to think about is that we never evolved not to be physically active. And the result of that is that when we're sedentary habitually sedentary, that leads to a lack of repair and maintenance. So that's the bad news, but the good news is that just a little bit of physical activity, you don't need to do very much stimulates a wide range of repair and maintenance mechanisms that overshoot any of the damage that the physical activity causes, right? So I like to think about it as like imagine spilling coffee on the floor, right? And then you clean up the floor, the floor is gonna be cleaner after you spill the coffee than before 'cause we overshoot the repair and maintenance.