First of all, from the purpose, where is the end of these two things? To complete a thing and a career, it is impossible to start immediately on a whim, but it is necessary to evaluate the "profit and loss" as a whole to decide.
Fitness needs to understand the functions of various muscles and bones, various types of equipment and correct strength skills in fitness movements, so as to make standardized and scientific movements, gradually improve the fitness effect and improve physical fitness.
The same is true of reading. Be clear about the purpose of your reading. Although reading more storytelling will naturally make progress, efficiency and methods are more important in this era. We don't want to get nothing after reading a book, and we don't know what we got. This is also an investment before reading, from literacy to mastery, forming your own knowledge system.
Therefore, it should be you who insists on sharing the cost between reading and fitness. In the end, both are active learning things, and both should be done more.