Lewis Mighty was diagnosed with neuroblastoma in 2008, a childhood cancer which attacks the sympathetic nervous system.

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This, in turn, reduces hyper-activation of the sympathetic nervous system, which is an established contributor to chronic hypertension.

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For instance, it could be that looking at females heightens sympathetic nervous system pathways which are associated with fight or flight impulses.

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Sleep deprivation also led to an increase in the activity of the sympathetic nervous system, which controls many of the body's "involuntary" functions.

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Beta blockers work by reducing activity in the sympathetic nervous system, which is one of the two major branches of the body's stress (or fight-and-flight) system.

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