Thursday, May 1, 2008

Body Types - Elastin and Collagen

We took a 20-hour anatomy training for yoga teachers this week with a woman named Ellen Heed. She's a body-worker and nutritional counselor in LA, and she has many fascinating ideas about how the body works. One of her central assertions is that the state of our connective tissue (or fascia) has a huge effect on how our bodies feel and move.

Connective tissue is the "stuff" that holds our bodies together. It wraps around and interpenetrates our bones, muscles and organs; supports our joints; allows our insides to slide around; provides a bed for blood and lymph vessels; contains immune cells; etc. Though not recognized as such by Western medicine, it is as much an "organ" as the heart or the stomach.
Some of the resistance we feel in a yoga stretch - especially deep, stubborn tension - comes from restriction in our fascia (rather than tension in the muscle bodies).

Fascial tissue is composed of two main molecules: collagen and elastin. Collagen is strong and inflexible, while elastin is more weak and stretchy. (See some nice microscope images here.) Different people have different collagen/elastin proportions in their tissue. Why? One speculation: tissue with more elastin has more intramuscular fat, which would be an evolutionary benefit for people living in cold climates.

This difference has many ramifications for yoga practice.

Folks with relatively more collagen in their fascia will tend to be naturally inflexible, because everything is bound together more tightly. It takes steady, consistent practice with a focus on pushing deeper into poses for a collagen-dominant yogi to get flexible. Because connective tissue gets more malleable in heat, a hot yoga practice can be extremely helpful. If not practicing in a heated room, many warm-ups are necessary before the poses start to feel good.

Ellen noted that the most dense connective tissue she's ever felt is in bodies from South India. She hypothesized that yoga may have arisen out of necessity for meditators to be able to sit comfortably.

Elastin-dominant yogis (such as myself) are naturally flexible because our connective tissue offers less resistance to stretching. We tend to towards collapsing and sagging in our joints, so it is important for us to work on alignment and long, strengthening holds. Because our fascia has more fat cells, it holds more toxins (which are mostly fat-soluble). When we practice hot yoga, the toxins release into the blood stream and can create nausea or dizziness. It's helpful to cleansing the body, but not pleasant.

Of course, some people are in between. Also, even people with lots of elastin may carry lots of muscular tension, so as a beginner it's hard to know where you fall on the fascial spectrum.

The health of connective tissue is intimately connected to overall physical health. With age, lack of movement, and/or dehydration, connective tissue dries out, adheres to itself, shrinks and gets tighter. This increases friction in the joints and can lead to arthritis. Tight fascia in the torso restricts breathing and the free movement of internal organs. Immune cells and nutrients circulate through the fluid matrix of connective tissue, so constricted fascia stagnates and becomes prone to disease. From this perspective, the benefits of stretching in yoga go far beyond doing a great looking pose.

For more information on connective tissue, see Job's Body by Deane Juhan.

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