Jeg gør nu noget, jeg aldrig har gjort før. Nemlig at gengive en hel artikel i sin fulde længde her på bloggen. Normalt sværger jeg til selv at gennemtygge originalmaterialet og formidle læringen. Men når en anden har gjort det for mig – og tilmed enormt velskrevet, så kan jeg kun bukke mig i støvet med den største ærbødighed.
Penetrating Postures, Part I: The Science of Yoga
By Alice G. Walton
This is the first of a two-part series on yoga: the second, “The Psychology of Yoga,” looks at the psychological changes that yoga has been shown to bring about.
Judging from the number of yoga mats I’ve seen toted around Manhattan in the last 15 years, I’m pretty sure I was the last person on the island to try it. My relationship with the practice started about six months ago, and I must admit, I fell for it – and hard. I was amazed at the changes it was effecting in my body, and even better, my mind. But the science nerd/Western medicine part of me wondered how, exactly, it was doing this. I could wager some guesses based on what I know about the body, but wanted to talk to some people who actually study this stuff for a living.
Stephen Cope is a therapist and director of the Institute for Extraordinary Living at the Kripalu Center for Yoga and Health in Massachusetts. He heads a program at the Center entitled “Yoga and the Brain,” in which researchers are studying yoga’s effect on the brain with MRI and other clever techniques. Cope explains that yoga brings about measurable changes in the body’s sympathetic nervous system – the one charged with propelling us into action during the “fight or flight” response to stress. However, because our lives today include business emails at 10 o’clock at night and loud cell conversations at the next table, our stress response often lingers in the “on” position at times it shouldn’t. Yoga helps dampen the body’s stress response by reducing levels of the hormone cortisol, which not only fuels our split-second stress reactions, but it can wreak havoc on the body when one is chronically stressed. So reducing the body’s cortisol level is generally considered a good thing.
Yoga also boosts levels of the feel-good brain chemicals like GABA, serotonin, and dopamine, which are responsible for feelings of relaxation and contentedness, and the way the brain processes rewards. All three neurotransmitters are the targets of various mood medications like antidepressants (e.g., SSRIs) and anxiolytic (anti-anxiety) drugs. The fact that yoga is linked to improved levels of these coveted chemicals is nothing to sneeze at.
Yoga has another bonus, says Sarah Dolgonos, MD, who has taught at the Yoga Society of New York’sAnanda Ashram. She points out that in addition to suppressing the stress response, yoga actually stimulates the parasympathetic nervous system, which calms us down and restores balance after a major stressor is over. When the parasympathetic nervous system switches on, “blood is directed toward endocrine glands, digestive organs, and lymphatic circulation, while the heart rate and blood pressure are lowered,” says Dolgonos. With the parasympathetic nervous system in gear, “our bodies can better extract nutrients from the food we eat, and more effectively eliminate toxins because circulation is enhanced. With parasympathetic activation, the body enters into a state of restoration and healing.”
There is also consensus that yoga boosts immune function, says Dolgonos. This benefit is probably due to the reduction of cortisol, mentioned earlier: too much of the pesky hormone can dampen the effectiveness of the immune system “by immobilizing certain white blood cells.” Reducing circulating cortisol “removes a barrier to effective immune function,” so yoga could help prevent illness by boosting immunity.
So let’s zoom in on yoga’s effects on the body even more (bear with me, this is really interesting). Researchers have discovered that yoga improves health in part by reducing a major adversary of the body: inflammation. Chronic inflammation, even low grade, is responsible for a litany of health problems from heart disease to diabetes to depression.
Paula R. Pullen, PhD, Research Instructor at the Morehouse School of Medicine, studies yoga’s effects on inflammation by looking at what’s happening in the bodies of heart failure patients who enroll in yoga classes. She has shown that after being randomly assigned to yoga or to standard medical care, patients taking yoga have significantly improved levels of biomarkers like C-reactive protein (CRP) and interleukin-6 (IL-6). If your eyes just glazed over, these findings are quite remarkable because they illustrate that yoga can actually affect the tiniest molecules, the ones that are widely known to predict risk for serious disease. Pullen underlines that reducing the body’s level of inflammation is incredibly important from a preventative standpoint. And yoga can help with this. “Yoga balances the body, the hormonal system, and the stress response. People tend to think of yoga as being all about flexibility – it’s not. It’s about rebalancing and healing the body.”
Though it’s been around for thousands of years, Western science is just beginning to understand how yoga exerts its effects. It will certainly be interesting to follow the research as it continues to reveal just what yoga is doing in the body and brain. Stay tuned for Part II of the yoga series!