It may conjure up images of bondage, discipline, sadomasochism, dominance, and submission, but many BDSM practictioners attribute the pleasurable pain of their fetish to the endorphin rush that accompanies the acting out of their fantasies. There's even a word for the state of a submissive's mind and body during and after consensual kinky play: subspace, often described as a " floaty " or " flying " feeling.

There's no denying that understanding how the human body works can lead to some intense sex. After all, as clichéd as it is, the brain is the biggest erogenous zone—and BDSM is no different.

"For all of us, endorphins bind to opiate receptors to naturally relieve pain," explains Maitresse Madeline Marlowe, a professional dominatrix who also works as a performer and director for Kink.com, a leading BDSM content producer. "Since BDSM play can include power exchange and masochistic acts, endorphins are one of the most common neurotransmitters [produced]."

As far back as 1987, leather activist and author Dr. Geoff Mains hypothesized that BDSM activity stimulated the release of endorphins, but scientists have yet to tease out the exact relationship between neurochemicals and S&M. But subspace does exist: Dr. Brad Sagarin, founder of the Science of BDSM research team and a professor of social and evolutionary psychology at Northern Illinois University, has compared it to runner's high, the sense of euphoria and increased tolerance for pain that some joggers feel after a long run. Except, obviously, one is caused by the asphalt flashing beneath your feet, the other by a whip swishing through the air.

In a 2009 study titled Hormonal Changes and Couple Bonding in Consensual Sadomasochistic Activity, Dr. Sagarin discovered that cortisol levels increase in subs and decrease in doms over the course of a scene. The effect was replicated in the research team's subsequent research: One 2016 preliminary study which measured the brain's executive functioning (i.e. basic control of our thoughts, emotions and actions) after participating in BDSM; and another that found that participants in the extreme S&M ritual known as the Dance of Souls (involving temporary piercings of the skin with weights or hooks attached) exhibited increases in cortisol throughout the ritual.

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"Like many potentially stressful or extreme experiences (e.g., sky-diving, fire-walking), individuals' bodies react to that stress when they engage in BDSM," Science of BDSM researcher Kathryn Klement told Broadly. "We interpret these cortisol results to mean that when people engage in BDSM play (as the receiver of sensations) or extreme rituals, their bodies release a hormone usually associated with stress. However, we've also found that people subjectively report their psychological stress decreasing, so there is a disconnect between what the body is experiencing, and what the individual is perceiving."