Every day, you experience part of the scientific basis for Hatha Yoga: your state of mind causes certain movements of energy within your body, and those movements in turn affect your bodily position. It’s simply body language.For example, disappointment, lethargy, and gloom cause energy to flow downward in the body, away from the brain. That flow in turn influences your posture: you’ll tend to slump, as if closing yourself off from life. The very words you use reflect that downward movement: “I feel down,” or “I feel low,” or “I feel depressed.”On the other hand, happiness, enthusiasm, and inspiration cause energy to flow upward toward the brain, which then comes alive. You straighten up into an expansive, life-affirming posture. You tend to inhale as if to embrace the world — and you smile. Your words, too, reflect that upward flow: “I feel on top of the world,” or “I’m in high spirits,” or “I’m feeling upbeat.”You’ve certainly experienced all this, even if you haven’t seen it as a chain of influence: mind affects energy, which in turn affects the body.