Heart rate variability (HRV) typically increases with parasympathetic activation (rest-and-digest response) and decreases with sympathetic activation (fight-or-flight response). The autonomic nervous ...

The sympathetic nervous system, which helps your heart and other vital organs function all the time, increases activity in response to danger or stress, preparing the body for extra demands. Stress is ...

Although aging is inevitable for all organs and tissues, why do some people age gracefully while others wear down faster? The answer might lie in a silent battle deep within our nervous system, which ...

The sympathetic nervous system was thought to have evolved with jawed vertebrates. But lampreys—jawless, parasitic fish that suck out the blood of their hosts—have a simple one, per recent research.

Opioid addiction, or opioid use disorder (OUD), is a major global health issue, and recovery from OUD is marked with high ...