What actually happens in the body as you get “in shape”?

Question

I used to run cross country in high school and while I wasn’t a superstar, I was certainly in great shape and could run many miles very easily. Today, at 45, I went for a run with my daughter, the first time that I’d done any running in probably 10 years. Well I’ll spare you the details but it didn’t go so well! But it got me thinking, what are the actual physiologic processes that occur when you go from sedentary to fit? On a cellular and an organ level, what actually happens?

In: Biology

Answer 1

As you run , you actually make more mitochondria in your muscles. Pretty cool to think about!