For me it's okay to take a day off when I'm feeling like this. For example, I usually use my stationary bike to get my legs moving when I'm feeling abnormally tired. Today for example, I wasn't feeling like waking up at 5:30 in the morning and decided to not go run this morning. I was okay with it because last week I hit 80 miles and this week up until today I was going strong so I knew it was time for a little break. So after coming home today I was able to get on the bike for two hours and how I feel a lot better. By resting today I will not be ready for tomorrow and the weekend long runs, which are crucial for marathon training.
I'll leave you with this graph that I saw today that was really stood out for me. It is a graph that compares by developed country the use of transit, biking, and walking and the obesity rate. It is clear that a correlation exist and between the two and the USA is definitely very car dependent. I hope that in the future more priorities can be placed on measures where it can be more practical for people to use other means and improve their health. It's not a us vs. them I think were all in it together and should work towards the greater good.