2nd and 3rd class leavers both have?

Both second class and third class levers have their fulcrum located at the end of the lever. They differ in the location of the load and effort. For third class levers the effort is in between the load and the fulcrum. For second class levers, the load is in between the effort and fulcrum

Because without physical activity, the body has extra "energy" if you will, and so when it is time for bed you are not tired, so you end up staying up all night. also there is probably an effect on your internal clock, which messes with your melatonin production which goes hand in hand with your sleep cycle