I'm not talking science but about personal experience. Like people claim meditation helps relieve stress which is true, so exercise does. You know running improves cardiovascular health and clears your mind, the satification you get after getting uncomfortable if you go hard is so good. Opening the morning with a run is a better way to start the day because you wake up through the run like a cold shower. I can talk about it all day, also any type of exercise is good and sharpens your brain but in my opinion it's best to give all effort for best results which is obivious and satification but build up gradually so you won't get injuries. Exercise is really helpful for any journey and it gives you the will to improve more and more, when you're going hard you teach yourself that it's all in the end, improving mentality will show you that it's all in the head, life is just a mind game. Best of luck!