“Spring fever” was once an unpleasant malady marked by swelling, loose teeth and seeping wounds, according to Reader’s Digest. Today, the term is more positive, indicating renewed enthusiasm, energy and an optimistic outlook. The difference is the increase in light: “First, it tells the circadian clock when dawn occurs, keeping our bodies synchronized to earth,” University of Pittsburgh professor Kathryn A. Roecklein told NBC. “Second, light has acute alerting effects that can make people feel less depressed, more alert, cognitively better able to process tasks and more energetic within just a few minutes.” #SpringFever