Rest + Exercise?!

My mind and body seem to be at odds. The balance that usually keep me level is out of sync I guess, the reason is myself or my mind. Rest is important, God was smart enough to know this before all this and He created the Sabbath which literally means rest. I need to give myself more rest - also what I realize is that without exercise I can't rest properly. I use to play football (soccer) and I was pretty fit and full of energy but since I left college I haven't done any of those things again and now my body is showing signs that exercise is needed again. My mind is sharper and my spirit is much more lifted when I have a good exercise regime that I stick with. I tend not to be so depressed and easily fatigued. I have to exercise my mind and I have been doing that by reading, working and reading my Bible more now than ever, but I seem to forget about the body which duly needs its exercise to syncronize with the mind - strong mind and weak body can work for a while but a strong mind and body always works. I have to push myself with everything I got to start exercising again - it is much easier said than done. I'm not over weight - I weigh less than 145 lb - but my muscles are lazy and unused and thus I need to revive them so that I can feel and perform much better. Working at a desk does this to you - you work long and by the time you get home you are mentally fatigued and you think your body is tired but it's really just your mind most of the times. I have two free weights who look at me every night and I always say next week I will start but I will give it a shot tonight. Wish me luck!