I've been going to the gym almost every day since I've started studying for the MCAT, the problem is that I've been lifting a lot of weights, so I've been getting really tired post-workouts.
I've been going to the gym at night right after a ~10 hours MCAT study session at the library. I'd be at the gym for an hour to an hour and 15 mins depending on what muscle group I'm focusing on.
I tried going to the gym first thing in the morning, but, first off, I'm not a morning person -- so waking up at 7 or 8 just so I can go workout, did not work out for me. When I got to the library at around 10, or sometimes 11, I was feeling tired and sleepy and not so energized because of the work out. So I tried that for a week, and it didn't work out for me, tried putting it in the middle of my study session, and that was even worse, since it was late AND I was tired and still had lots of studying to do, and I wasn't leaving the library till late at night. So I eventually went back to the routine of study for 9 to 11 hours then hit the gym at night, go back home, kick back and relax for an hour or two and then pass out.
I do warn that if you're gonna start lifting like me, and study as much, you're going to burn A TON of calories, and studying for a long time requires a lot of calories. I was getting so hungry that packing lunch became an issue, since if I was even a tiny bit hungry I would lose focus. So I started preparing feasts (I'd eat maybe 4 turkey sandwiches, a banana, ~70ounces of water, a thing of cottage cheese or sometimes a boiled egg, a coffee, a little bag of almonds, and something else sweet) all within that ~10 hours study session. I do feel very healthy and good though, a sandwich and a little snack every 2 hours plus gymming every day has put me in the best shape of my life.
Weird, I never ever thought that I'd be getting in the best shape of my life during a period of my life that involves sitting for 10 hours on my ass every day at the library