For some reason I feel more and more tired the closer I get to finishing. It applies to finishing a programming task late at night or running a certain distanc

For some reason I feel more and more tired the closer I get to finishing. It applies to finishing a programming task late at night or running a certain distance. When I know I'm close to the goal, suddenly my eyelids start to droop or my legs feel heavy. I fix it by thinking that maybe I will start another task tonight or run an extra loop on the trail... and sometimes I do, which is an extra bonus.