Importance of connection with lover

• Anxiety, cortisol, and attachment predict plasma oxytocin (higher oxytocin reduces anxiety where partner is supportive, but is accompanied by higher cortisol where there is distress and no attachment to partner)
• Effects of different kinds of couple interaction on cortisol and heart rate responses to stress in women (supportive touch, rather than verbal encouragement, lowers stress response in women)
• Warm Partner Contact Is Related to Lower Cardiovascular Reactivity (handholding and hugs lower stress response)
• Kissing reduces allergic skin wheal responses and plasma neurotrophin levels (kissing improved eczema and alleries)
• The influence of marital adjustment on 3-year left ventricular mass and ambulatory blood pressure in mild hypertension (quality of contact in marriage linked to increases/decreases in blood pressure over 3 years)
• Frequent Sex Can Reduce Risk Of Colds (moderate rates of intercourse are best for the immune system) Study:

  Sexual frequency and salivary immunoglobulin A (IgA)
  Charnetski CJ, Brennan FX.
  Psychol Rep. 2004 Jun;94(3 Pt 1):839-44.
  Department of Psychology, Wilkes University, Wilkes-Barre, PA 18766, USA. charnets@wilkes.edu
  112 college students reported the frequency of their sexual encounters and were divided into four categories: none, infrequent (less than once a week), frequent (one to two times per week), and very frequent (three or more times per week). Participants also described their overall sexual satisfaction. Saliva samples were collected and assayed for salivary immunoglobulin A (IgA). Individuals in the frequent group showed significantly higher levels of IgA than the other three groups, which were comparable. Data on length of relationship and sexual satisfaction were not related to the group differences.

• Penile — vaginal intercourse is better: evidence trumps ideology (The ethical practice of sex therapy, education and research requires the elimination of prevailing sexological prejudices. Empirical research demonstrates that different sexual behaviours differ in many physiological and psychological domains. These differences are remarkably consistent in revealing an association between specifically penile-vaginal intercourse and indices of better physiological and psychological function.)
• Slimness is associated with greater intercourse and lesser masturbation frequency (Slimmer waist in men and in the sexes combined and slimmer hips in men and women were associated with greater penile-vaginal intercourse, and less with masturbation)
• Blood pressure reactivity to stress is better for people who recently had penile-vaginal intercourse than for people who had other or no sexual activity (Persons who reported penile-vaginal intercourse (but no other sexual activities) had better stress response (less reactivity and/or lower baseline levels) than persons reporting other or no sexual behaviors.)
• Sex may keep stress at bay (Penile/vaginal sex better for reducing stress than other types of sexual activity) Entire study
• A preliminary report relating frequency of vaginal intercourse to heart rate variability, Valsalva ratio, blood pressure, and cohabitation status (greater HRV and lower DBP were both associated with greater penile-vaginal intercourse - but not with masturbation or non-coital sex with a partner - in cohabiting subjects, but not in non-cohabiting subjects.)
• Vaginal intercourse frequency and heart rate variability (greater HRV was associated with greater penile-vaginal intercourse (but not masturbation or non-coital sex with a partner), but no change in DBP)
• Age at first intercourse is inversely related to female cortisol stress reactivity (women reporting earlier first intercourse had less intense cortisol increases in response to the stressor, and faster recovery from the stressor)
• Alexithymia Is Inversely Associated with Women's Frequency of Vaginal Intercourse (difficulty recognizing, identifying, and communicating emotions, reduced fantasy capacity, and an externally oriented cognitive style (alexithymia) associated with less penile-vaginal intercourse in women.)
• Intercourse Orgasm Consistency, Concordance of Women's Genital and Subjective Sexual Arousal, and Erotic Stimulus Presentation Sequence (penile-vaginal intercourse tends to help women synch up actual arousal with emotional arousal)
• Sex and death: are they related? Findings from the Caerphilly cohort study (Longer lives are associated with regular sex.)

  This study is often billed as "proof that orgasm leads to longevity," but it confounds the benefits of intimacy with the benefits of orgasm. The men in this study were middle aged (45-59) at the start of a 10-year study, with results published in 1997. Almost all were married. The question proved so embarrassing that the men in the study asked that it be dropped part way through, so they may also have been unwilling to answer honestly. In any case, the question about sex did not isolate orgasm. In other words, masturbation wasn't addressed. So we don't know if those masturbating instead of having intercourse were better or worse off.

  In short, although this study is much bandied about by orgasm enthusiasts, it is pretty shaky as proof of the benefits of orgasm. It may show that intimacy, or a better quality relationship, increases longevity. Many people in the subjects' age bracket generally aren't having sex at all, so those who were, were no doubt better off...but not necessarily because of the orgasms.

• Depression-Like Behavior and Stressor-Induced Neuroendocrine Activation in Female Prairie Voles Exposed to Chronic Social Isolation (isolation in a socially monogamous rodent induces both behavioral and neuroendocrine changes that are relevant to depression)
• Social stimuli cause changes of plasma oxytocin and behavior in guinea pigs (plasma oxytocin levels synch up in cohabiting pairs)
• Prognostic importance of marital quality for survival of congestive heart failure (marital quality is statistically significant in the prediction of patient mortality)
• Stable partnership and progression to AIDS or death in HIV infected patients receiving highly active antiretroviral therapy: Swiss HIV cohort study (stable partnership is associated with a slower rate of AIDS or death in HIV infected patients)

Overview of effects of oxytocin

The research listed here does not prove that controlled intercourse grants the benefits listed here. None of this research was done on controlled intercourse. However, this research does suggest that there are potential health gains from behavior that emphasizes the steady production of oxytocin. By implication, the affectionate, caring contact of the type emphasized in the Ecstatic Exchanges (from Peace Between the Sheets) is likely to promote the presence and benefits of oxytocin.

• Oxytocin has dose-dependent developmental effects on pair-bonding and alloparental care in female prairie voles (size dose of oxytocin changes behaviors)

  Here's abstract:

  The present study examines the developmental consequences of neonatal exposure to oxytocin on adult social behaviors in female prairie voles (Microtus ochrogaster). Female neonates were injected within 24 h of birth with isotonic saline or one of four dosages of oxytocin (OT). As adults, females were tested in an elevated plus-maze paradigm (a measure of anxiety and exploratory behavior), and for alloparental behavior and partner preferences. At 2 mg/kg OT, females took longer to approach pups, but were the only group to form a statistically significant within-group partner preference. At 4 mg/kg OT, females retrieved pups significantly more frequently but no longer displayed a partner preference; while females treated developmentally with 8 mg/kg spent significantly more time in side-to-side contact with a male stranger than any other treatment group. OT may have broad developmental consequences, but these effects are not linear and may both increase and decrease the propensity to display behaviors such as pair-bonding.

• Neuro Endocrinol Lett. 2009 Aug 26;30(3):335-342. [Epub ahead of print] "Oxytocin and carbetocin effects on spontaneous behavior of male rats modulation by oxytocin receptor antagonists. (oxytocin administered via peripheral injection does cross blood/brain barrier)
• Oxytocin may mediate the benefits of positive social interaction and emotions (oxytocin may explain benefits of touch therapies, social interaction, and meditation)
• More frequent partner hugs and higher oxytocin levels are linked to lower blood pressure and heart rate in premenopausal women. (frequent hugs between spouses/partners are associated with lower blood pressure and higher oxytocin levels in premenopausal women)
• Oxytocin, a mediator of anti-stress, well-being, social interaction, growth and healing (positive interaction involving touch and psychological support may be health-promoting due to oxytocin, oxytocin production increases sensitivity to oxytocin)
• The oxytocin receptor system: structure, function, and regulation (oxytocin has far reaching effects on mind and body)
• Oxytocin stimulates its own production by activating oxytocin receptors, which stimulate cells to produce more oxytocin. Kerstin Uvnäs Moberg, The Oxytocin Factor (Cambridge: Da Capo Press, 2003) pp. 60, 61

Counters infection and allergic reaction, speeds healing

• Hostile Marital Interactions, Proinflammatory Cytokine Production, and Wound Healing (marital conflict slows wound healing)
• Stress and Wound Healing (Dr. Kiecolt-Glaser's work on stress and wound healing)
• Social experience influences hypothalamic oxytocin in the WHHL rabbit (The concentration of peripheral OT was the highest in the rabbits paired with a familiar rabbit at all times. The Stable group also exhibited significantly less aortic atherosclerosis.)
• Inhibition of Calotropis procera Latex-Induced Inflammatory Hyperalgesia by Oxytocin and Melatonin (oxytocin ameliorated hyperalgesic response)
• Oxytocin protects against sepsis-induced multiple organ damage: role of neutrophils (oxytocin strongly protects organs from damage due to blood infection)
• Kissing reduces allergic skin wheal responses and plasma neurotrophin levels. (kissing may have positive implications for allergic patients)
• Social facilitation of wound healing (oxytocin speeds wound healing)

Counters addiction and overeating

• Oxytocin Knockout Mice Demonstrate Enhanced Intake of Sweet and Non-Sweet Carbohydrate Solutions (oxytocin counters use of sweets, not fats)
• Oxytocin null mice ingest enhanced amounts of sweet solutions during light and dark cycles and during repeated shaker stress (oxytocin counters use of sweets)
• Oxytocin and addiction: a review (oxytocin counters addiction and soothes withdrawal symptoms)
• Chronic exposure to Delta(9)-tetrahydrocannabinol downregulates oxytocin and oxytocin-associated neurophysin in specific brain areas (oxytocin declines in reward circuitry with pot use)
• Prevention of cannabinoid withdrawal syndrome by lithium: involvement of oxytocinergic neuronal activation (effects of lithium against the cannabinoid withdrawal syndrome are mediated by oxytocinergic neuronal activation and subsequent release and action of oxytocin within the CNS)
• Massage therapy improves the management of alcohol withdrawal syndrome. (Massage may aid detoxification for alcohol. [Oxytocin rises during massage.])
• Role of oxytocin in the neuroadaptation to drugs of abuse (Multiple experiments demonstrating that oxytocin decreases self-administration, dependence and tolerance of addictive drugs. Oxytocin does this by modulating dopamine receptors within reward circuitry.)
• Microinjection of oxytocin into limbic-mesolimbic brain structures disrupts heroin self-administration behavior: a receptor-mediated event? (injection of oxytocin decreases the self-administration of heroin in heroin-tolerant rats)
• Oxytocin and neuroadaptation to cocaine (both oxytocin and vasopressin have modulatory effects on opiate and alcohol tolerance and dependence)
• Alcohol preference in mice lacking the Avpr1a vasopressin receptor (LIKE OXYTOCIN, VASOPRESSIN CAN INHIBIT DRUG USE)

Counters stress and improves maternal behavior

• Effects of Partner Support on Resting Oxytocin, Cortisol, Norepinephrine, and Blood Pressure Before and After Warm Partner Contact (Greater partner support (based on self-report) was related to higher plasma oxytocin in men and women. BP also declined in women.)
• Effects of different kinds of couple interaction on cortisol and heart rate responses to stress in women (Women with positive physical partner contact before stress exhibited significantly lower cortisol and heart rate responses to stress but no different plasma oxytocin levels compared to women who received social support or no social interaction. All women had long-term partners.)
• Oxytocin: a natural means of treating psychological stress (Oxytocin reduces stress response. Hypnosis increases oxytocin.)
• Intranasal oxytocin administration attenuates the ACTH stress response in monkeys (oxytocin anti-stress effects due to increase in brain oxytocin and not due to blood oxytocin)
• Social support and oxytocin interact to suppress cortisol and subjective responses to psychosocial stress (oxytocin is the biological mechanism by which social support positively affects health and counteracts stress)
• Social isolation and cardiovascular disease: an atherosclerotic pathway? (positive effects of social support on the cardiovascular disease is mediated primarily through mechanisms associated with the release of oxytocin)
• Dose-response relationship between plasma oxytocin and cortisol and adrenocorticotropin concentrations during oxytocin infusion in normal men (inverse relationship between cortisol (and acth) and oxytocin in humans)
• Energy conservation in stressed rats exposed to an oxytocin-injected cage mate (elevated oxytocin in one rat decreases stress response of other rats in its presence)
• Social stress blocks energy conservation in rats exposed to an oxytocin-injected cage mate (oxytocin in one individual reduces stress response (cortisol sympathetic activation) in those close to them — through pheromones)
• Female oxytocin gene-knockout mice, in a semi-natural environment, display exaggerated aggressive behavior (oxytocin deficiency greatly increases aggressive behavior)
• Female oxytocin-deficient mice display enhanced anxiety-related behavior (oxytocin reduces anxiety in rodents)
• Anxiety and Stress Responses in Female Oxytocin Deficient Mice (oxytocin deficient mice have a lot of anxiety)
• Marital Stress: Immunological, Endocrinological, and Health Consequences (Marital conflict increases stress hormones. Also, declines in marital satisfaction appear to be a stable response to the first year or two of marriage)
• Vasopressin and oxytocin excite distinct neuronal populations in the central amygdala (vasopressin and oxytocin regulate the autonomic expression of fear)
• Biobehavioral responses to stress in females: tend-and-befriend, not fight-or-flight (human females tend-and-befriend under stress— probably due to oxytocin)
• Brain oxytocin inhibits basal and stress-induced activity of the hypothalamo-pituitary-adrenal axis in male and female rats: partial action within the paraventricular nucleus (oxytocin inhibits stress response in both males and females)
• Inhibitory effect of oxytocin on corticotrope function in humans: are vasopressin and oxytocin ying-yang neurohormones? (oxytocin (ot) and vasopressin (vp) may have opposing effects on cortisol levels)
• Brain oxytocin inhibits basal and stress-induced activity of the hypothalamo-pituitary-adrenal axis in male and female rats: partial action within the paraventricular nucleus (brain oxytocin reduces stress)
• Improved conditioned avoidance learning by oxytocin administration in high-emotional male Sprague-Dawley rats (oxytocin is an antistress hormone in rats bred to be highly emotional and lazy)
• Acute cocaine alters oxytocin levels in the medial preoptic area and amygdala in lactating rat dams: implications for cocaine-induced changes in maternal behavior and maternal aggression (less oxytocin results in more aggression and less caring)

Pain reduction

• Repeated Massage-Like Stimulation Induces Long-Term Effects on Nociception: Contribution of Oxytocinergic Mechanisms (oxytocin may explain why massage reduces pain)
• Involvement of opioid receptors in the oxytocin-induced antinociception in the central nervous system of rats (oxytocin reduces pain)
• Oxytocin mediates stress-induced analgesia in adult mice (higher levels of oxytocin reduce pain signals reaching then brain- so less pain)

Counters depression

• The interface of oxytocin-labeled cells and serotonin transporter-containing fibers in the primate hypothalamus: a substrate for SSRIs' therapeutic effects? (SSRIs' therapeutic effects on social affiliation and anxiety may be mediated in part through components of the oxytocin system)
• Evidence that oxytocin exerts anxiolytic effects via oxytocin receptor expressed in serotonergic neurons in mice (Oxytocin appears to trigger serotonin release to reduce anxiety-related behavior.)
• Oxytocin as a possible mediator of SSRI-induced antidepressant effects (oxytocin release is an important aspect of the pharmacological actions of SSRIs)
• Sustained desensitization of hypothalamic 5-Hydroxytryptamine1A receptors after discontinuation of fluoxetine (serotonin and oxytocin: 60 days after discontinuation of prozac oxytocin response was still low compared to controls)
• AVP- and OT-neurophysins response to apomorphine and clonidine in major depression (vasopressin activity reduced in those with depression)

Inhibits cancer

• Individual Differences in Emotional Expressivity Predict Oxytocin Responses to Cortisol Administration: Relevance to Breast Cancer? (low levels of oxytocin may explain why reduced emotional expression has been consistently related to fast progression of breast cancer)
• Biological relevance of oxytocin and oxytocin receptors in cancer cells and primary tumors (oxytocin regulates cell proliferation)
• Oxytocin and Oxytocin Receptors in Cancer Cells and Proliferation (oxytocin inibits breast cancer)
• Evidence of oxytocin/oxytocin receptor interplay in human prostate gland and carcinomas (oxytocin inibits prostate cancer)

Sexual receptivity and erectile health

• Oxytocin maintains as well as initiates female sexual behavior: effects of a highly selective oxytocin antagonist (oxytocin increases the receptivity of females)
• Effects of alpha melanocyte stimulating hormone on magnocellular oxytocin neurones and their activation at intromission in male rats (oxytocin neurones are involved in the central regulation of male sexual behaviour - oxytocin induces penile erection and enhances copulatory behaviour when given centrally)
• The role of oxytocin and the paraventricular nucleus in the sexual behaviour of male mammals (oxytocin involved in erection and sexual behavior)
• Prior exposure to oxytocin mimics the effects of social contact and facilitates sexual behaviour In females (oxytocin increases the receptivity of females)
• Oxytocin receptor is expressed in the penis and mediates an estrogen-dependent smooth muscle contractility (Oxytocin levels in blood not necessarily a good indicator of CNS effects.)
• Chronic fluoxetine inhibits sexual behavior in the male rat: reversal with oxytocin. (oxytocin may alleviate erectile dysfunction)
• Sexual impotence is associated with a reduced production of oxytocin and with an increased production of opioid peptides in the paraventricular nucleus of male rats (oxytocin imbalance may underlie impotence)
• Effect of American ginseng (Panax quinquefolium) on male copulatory behavior in the rat (ginseng may increase sexual desire and performance by inhibiting prolactin)

Miscellaneous benefits associated with oxytocin

• Nastech Awarded Patent Covering Treatment and Prevention of Breast Cancer (oxytocin nasal spray for discouraging growth of breast cancer and psychiatric disorders)
• Does singing promote well-being?: An empirical study of professional and amateur singers during a singing lesson (oxytocin rose significantly after singing)
• Changes in cerebrospinal fluid neurochemistry during treatment of obsessive-compulsive disorder with clomipramine (increased oxytocin, and reduced cortisol releasing hormone, may be mechanism by which drug treatment reduced obsessive-compulsive disorder)
• Oxytocin infusion reduces repetitive behaviors in adults with autistic and Asperger's disorders with clomipramine (patients with autism spectrum disorders showed a significant reduction in repetitive behaviors following oxytocin infusion in comparison to placebo infusion)
• Oxytocin improves long-lasting spatial memory during motherhood through MAP kinase cascade (oxytocin involved in learning and memory)

Trust associated with higher levels of oxytocin

• Oxytocin increases trust in humans (intranasal administration of oxytocin causes a substantial increase in trust among humans, thereby greatly increasing the benefits from social interactions.)
• Oxytocin is associated with human trustworthiness (trust associated with higher blood levels of oxytocin)
• The neurobiology of trust (being trusted raises oxytocin levels)

Monogamy (which is associated with increased longevity and better health)

• Social experience and social context alter the behavioral response to centrally administered oxytocin in female Syrian hamsters (oxytocin increases attraction between partners, but not between unfamiliar potential mates)
• Peripheral Pulses of Oxytocin Increase Partner Preferences in Female, but Not Male, Prairie Voles (oxytocin affects female choices, males more influenced by vasopressin)

More Research

Evolution, mating and bonding

Limbic system and reward circuitry

Post-coital hangover

Potential health risks

Return to detailed outline of all research

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