"Although she was only in her early forties, Lea feared for her life, convinced she was on the verge of a heart attack. Sometimes her heart pounded so fiercely and quickly she thought it would pop right out of her chest, and she swears she could see it beating under her skin. Her racing heart put such a strain on her lungs that they became sore. When Lea had one of these spells, she could barely walk up a hill or a flight of stairs. Despite feeling exhausted, the nervous energy created by her racing heart made her anxious and kept her up late every night. And yet at other times, Lea felt as if she were moving underwater pressing fatigue, relentless in its grasp, weighed down her limbs and pushed on her head. Her voice grew hoarse as the tissue around her Adam's apple became puffy and tender, and she was always cold. Despite having lost weight easily after the birth of each of her first three children, Lea's body continued to balloon after her fourth child was born. Her puffy eyes and face vexed her deeply and, unsurprisingly, she also battled chronic depression. Lea visited several medical doctors and had numerous cardiovascular tests done, only to be told she was fine. Natural medicine cardiologists she consulted came to the same conclusion. Finally a friend suggested she get tested for Hashimoto's disease, an autoimmune disease that destroys the thyroid, and sure enough, her blood test came back positive. "Great!" she thought. "Now that I know what's wrong with me, I can finally get some help!" A physician prescribed thyroid hormone, which quickly brought her thyroid hormone levels into a normal range. Lea's symptoms improved for a while, but then slowly returned: The weight would not budge and the chronic fatigue made a comeback. So did the terrifying episodes when she thought her heart would jump out of her chest. "What is going on?" Lea asked her doctor. "Why do I still have hypothyroid symptoms when my blood tests are normal?" Though it weighs less than an ounce, the butterfly-shaped thyroid gland is a formidable figure in the intricate dance of human physiology. The thyroid is the spark plug for energy production--it controls the rate of energy production, maintains body temperature, helps regulate moods and emotions. When one sees the thyroid function within the intelligent matrix of the human body, taking into account the immune system, hormone balance, and even brain function, it becomes easy to see why addressing the entire body--as demonstrated in Why Do I Still Have Thyroid Symptoms?--is a very logical way to support the thyroid."