Re-Examining Breast Health
Sarvangasana (Shoulderstand), Halasana (Plow Pose), and Setu Bandha Sarvangasana (Bridge Pose) all work to improve thyroid-parathyroid function by employing a gentle chinlock. According to yogis, the chinlock squeezes blood from the area; then, as you release the lock, fresh, oxygenated blood circulates more freely in and around these organs.
Yogis also believe that forward bends tend to lower blood pressure and pacify the adrenals and other components of the sympathetic nervous system that are engaged in the fight-or-flight response. Iyengar yogis teach that you must calm overactive adrenals before you can activate them healthily, so it's good to do some forward bends before practicing twists and backbends. Twists like Ardha Matsyendrasana I (Half Lord of the Fishes Pose) provide the ovaries, pancreas, and adrenals with the same squeezing and soaking action the chinlock provides for the thyroid and parathyroid. Backbends like Dhanurasana (Bow Pose) are also thought to energize these abdominal organs. While medical science has yet to conclusively document most of these effects, there's certainly no harm in hedging your bets until more evidence is in.
The immune system also plays a major role in protecting us from breast cancer. Just as predatory insects maintain the delicate balance on an organic farm by feeding on crop-eating pests, the immune system keeps the body healthy and strong by sensing and devouring mutated cells. Yoga therapeutics holds that inverted poses are especially beneficial for immune function. Poses like Sirsasansa (Headstand) and Sarvangasana (Shoulderstand) are very potent but off-limits to some students due to neck injuries or lack of strength or experience. But a simple Viparita Karani (Legs-Up-the-Wall Pose) is accessible to everyone, as well as comfortable and deeply nourishing. In general, since stress taxes the immune system, restorative poses and Savasana (Corpse Pose) can play an important role in immune system health.
Yoga can also contribute to strengthening one particular component of our immune network, the lymphatic system. Lymph is the fluid that surrounds all of our cells. Just like our bodies, our cells take in nutrients and excrete wastes. If lymphatic fluid doesn't flow, cells are surrounded by their own waste. Bathed in cellular debris and toxins, they're unable to receive proper nutrition.
Unlike the blood, which is pumped through the body by the heart, lymph depends on body movement to keep it flowing. Many kinds of movement can help circulate lymph: massage, deep breathing, even the flow of blood in a nearby vein. But exercise is one of the best methods for circulating lymph, and yoga excels at encouraging lymph flow.
Along with supporting lymph flow throughout the body, yoga can help stimulate the lymph nodes. These specialized glands, central to the prevention of disease, manufacture lymphocytes (a type of white blood cell) and filter wastes and other unwanted matter from lymph fluid. The largest clusters of lymph nodes in the body are located in the armpits, adjacent to the breasts.