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PROBLEM: The flight or fight response -- the natural response to stress -- essentially puts the nervous system in overdrive. So it's no surprise that its opposite state, known as the relaxation response to stress, is associated with feeling good, in a general sense. People are able to evoke the relaxation response by repeating a yoga pose, prayer, or mantra while disregarding other thoughts, and it's been shown to protect against psychological disorders like anxiety and depression as well as physical conditions like hypertension, cardiovascular disease, and types of cancer that are exacerbated by stress.

METHODOLOGY: Researchers at the Benson-Henry Institute for Mind/Body Medicine at Massachusetts General Hospital and Beth Israel Deaconess Medical Center Subjects trained 26 adults with no prior experience in this type of meditation for eight weeks. They practiced deep breathing, repeated mantras, and learned to ignore intrusive thoughts. Initially, they were given blood tests immediately before and 15 minutes after listening to a 20-minute health education CD. This was repeated after their training, only with a CD that guided them in their meditation. Twenty-five other participants, who had long-term experience in evoking the relaxation response, were tested as well.

RESULTS: All of the subjects' blood samples revealed changes in gene expression following meditation. The changes were the exact opposite of what occurs during flight or fight: genes associated with energy metabolism, mitochondrial function, insulin secretion, and telomere maintenance were turned on, while those involved in inflammation were turned off. These effects were more pronounced and consistent for long-term practitioners.