need excersizes to do before work

goku89

i used to work out, sometimes like an 8 mile run before work, i thought i could do it(my first year of getting seriously into shape too) but at work i'm tired and listless and i have to work directly with people and cook and focus, focus focus but i can't do it. i figure it's because i'm still getting used to this, does anyone have any simple cardio or something to do that won't ruin your work day? thanks.