Talk to General Physician on Sleeping Insomnia After Exercise

if I do exercises like running or sit-ups i can't sleep even I am feeling sleepy and tired. it will take more than one hour to sleep and will wake up automatically after 3 or 4 hours then again can't sleep even water will come from my eyes. walking and push ups will make no problem after these exercises I can sleep straight 8 hours. I want to improve my health with exercise and want to join gym but how I can improve my sleep. please someone help