The natural world in springtime endures obvious, drastic changes: first rain and gloom, then a mood-swing to sunshine and flowers. Parallel swings occur in our bodies and minds, but often, we're too preoccupied to notice. Emotions and mental states can run the gamut as days grow longer, and physical conditions ranging from aggravated allergies and colds to leftover flab and lethargy from winter can frustrate the renewal that has been the season's focus across cultures and throughout centuries.