Based on the context and the answer, generate a question. 

Context: Tonight , for the first time in about a week , I felt REALLY GOOD . And this was the best run I ' ve had since last week 's 9 miler on Monday . The weather was in the mid to high 60s which is a little cooler than it has been and perfect for me ( well not PERFECT , but I 'll take it . Perfect would be somewhere in the mid 50s ) Set off conservatively and really focused on running relaxed , not letting myself go too hard even though I finally felt good and not listless .

Answer:

The author went on a jog which made her body release endorphins that are natural mood elevators .



Why does the author feel really good for the first time in a week ?