If you don't, you'll just end up working yourself into a problematic state without accomplishing anything.
Some activity is great for you, whether it's bike riding, figuring out mathematical equations or simply cooking dinner. Inactivity serves it's purpose by controlling the amount of activities you do for your own sake. Also, you've got to have time to think. It's a necessity to collect your thoughts every chance you get. Don't work so much to the point where you can't even think. Your mind is sensitive, so don't overuse it because you only get one. The only thing you'll accomplish is suffering. To summarize, Thomas Jefferson's theory of ''being active all the time is good'' is completely wrong. You always need to take time to rest, think and give your mind a break. You'll get more done than you'd think. You'll accomplish not overusing your mind and body. Accomplishment isn't always about how much you can get
done.