The Good Vibrations Guide to Sex (10 page)

The Sexual Response Cycle

The
sexual response cycle
is the term used to refer to the physiological changes our bodies go through during arousal and orgasm. Masters and Johnson can be credited with popularizing this phrase in the sixties. Their laboratory studies of thousands of men and women engaging in a variety of sexual activities led them to develop the concept of a four-stage cycle of sexual response. These four stages are: excitement, plateau, orgasm, and resolution.

According to the Masters and Johnson model, the excitement phase in both men and women is characterized by an increase in heart rate, muscle tension, and blood flow. Increased blood flow results in engorgement of the genitals, lips, and breasts; general body warmth; and flushed skin. Women’s responses include vaginal lubrication, swelling of the clitoris and vaginal lips, and a lifting up or ballooning of the inner vagina and the uterus. Men’s responses include erection, contraction of the scrotum, and elevation of the testicles. Many men and women also experience nipple erection. The entire body experiences muscular tension and warmth. Arousal frequently produces increased sensitivity to stimulation as well as reduced sensitivity to pain.

The plateau phase is a continuation and heightening of the excitement phase. In women, the clitoris retracts under the clitoral hood; the outer third of the vagina becomes even more congested with blood; and the uterus becomes fully elevated, creating a tenting effect in the inner vagina. Men often secrete a clear glandular fluid that may contain some stray sperm. Often referred to as “pre-come,” this fluid is the reason withdrawal before ejaculation is an ineffective method of birth control.

Orgasm is the discharge of sexual tension through involuntary muscular contractions. These contractions take place in the outer third of the vagina and the uterus in women and in muscles throughout the pelvic region in both men and women. Anywhere from three to fifteen contractions occur, at intervals of eight-tenths of a second. Orgasm releases the blood from engorged genital tissue.

During resolution, the body returns to an unaroused state. Heart rate, breathing, and blood pressure return to normal; the body flush subsides; and genitals return to their usual size, shape, and color. If you’ve been aroused but haven’t had an orgasm, it will take somewhat longer for the blood to ebb out of your congested genitals and for resolution to be completed.

Your body undergoes certain distinct physiological changes regardless of what kind of stimulation you are receiving or how subjectively different your arousal and orgasm may feel. Please don’t despair, however, if you’ve never noticed your skin flush during arousal, if you find it hard to conceive of eight-tenths of a second, or if you’re not sure if you’ve ever experienced “the plateau phase.” Masters and Johnson’s sexual response cycle is a fairly arbitrary construct. They interpreted their data selectively, to create a model that could be applied to men and women alike. In fact, few of us experience sexual arousal as though our bodies were spaceships moving inexorably from one discrete launching phase to another as we lift off toward a guaranteed orgasm.

Masters and Johnson’s emphasis on the physiology of sexual response has influenced sex therapy and the treatment of people’s sexual dysfunctions since the sixties. The idea that sexual response is not only natural, but quantifiable, is appealing. Who wouldn’t be tempted by the notion that if we’re just taught to push the right physiological buttons, sexual pleasure will automatically follow? The trouble with this mechanical approach to sex is that it doesn’t take into account the huge influence that subjective conditions, social factors, and psychological readiness have on our experience of sex. Furthermore, physiological arousal doesn’t necessarily indicate a readiness to have sex. Just because a woman is lubricating or a man has an erection doesn’t mean she or he feels like being sexual. People need to
desire
sex to enjoy
having
sex.

In the seventies, sex therapist Helen Singer Kaplan amended the Masters and Johnson sexual response cycle to include desire as a prerequisite to excitement and orgasm, and this model (desire, excitement, and orgasm) has been widely followed since then. Yet, as the lesbian sex therapist JoAnn Loulan points out, even desire isn’t necessarily required to initiate a satisfying sexual experience. If you enter into sex with willingness, desire may follow. Desire doesn’t necessarily begin with sexual stimulation or come to an end upon orgasm. Perhaps the only absolute truth about sexual response is how fundamentally fluid it is. One can move from arousal to desire, from excitement to indifference, from boredom to passion, from orgasm to arousal and back again.

Desire

Sex therapists had only just begun to explore the powerful, subjective complexities of sexual desire when Viagra burst on the scene (and the stock market) in the late nineties. The resulting avalanche of interest in the
physiology
of sexual response has all but buried any more nuanced discussions of desire. In recent years, the concept of sexual desire has become so medicalized that so-called “desire disorders” are now clinically categorized in the
DSM
(
Diagnostic and Statistical Manual of Mental Disorders
). “Female sexual dysfunction” is a particularly broad category—never mind that fifty years ago, women were pathologized for having “too much” desire, now they’re pathologized for having “too little.” If you are experiencing difficulty with arousal or orgasm, or admit to having “low interest” in sex, you have a medically treatable condition. And you’d better believe that pharmaceutical companies are ready and willing to treat you.

A breathtaking array of products is being developed to relax smooth muscle cells (thereby facilitating erection), enhance genital blood flow, and increase vaginal lubrication: Prostaglandin creams, androgens such as testosterone and DHEA, and the amino acid L-arginine are all being touted as modern-day aphrodisiacs. The prevailing medical models put such focus on constructing firm erections and supple, lubed vaginas that they almost seem to lose sight of the men and women attached to those high-functioning genitals.

Sure, some of these products may ultimately prove to be useful sexual enhancers. However, we question the motives of snake oil salespeople such as the doctor who promotes his vaginal cream with the promise that it “basically eliminates the need for foreplay.” Do we really need gels marketed to “increase clitoral sensitivity” that cost thirty times more than any water-based lubricant? Our culture has a knee-jerk affinity for quick-fix solutions: We’d rather pop a pill, apply a lotion, or switch on a medically approved vacuum device than take the time and energy to cultivate sexual self-awareness.

As we’ll discuss in the next chapter, sexual desire fluctuates over the course of our lives, for numerous situational, emotional, cultural, and hormonal reasons. We hope that everything you read in this book will inspire you to take the long view and let your own authentic desires be your guide through a lifetime of sexual flux.

Know Yourself: Hormones and Desire

You’ve probably heard or read that hormones affect sexual desire. Growing interest in the physiology of arousal have put the spotlight on the role hormones play in sexual desire and response.

Hormones are chemical messengers produced in one part of the body that stimulate activity in another part. While there are many types of hormones, those that get the most press belong to the category of so-called “sex” or “steroid” hormones: estrogen, testosterone, and progesterone. Progesterone is present only in women, but estrogen and testosterone are present in both women and men. As women have up to ten times more estrogen than men during their reproductive years, and men have over ten times more testosterone than women, it’s often claimed that differences between these two hormones “explain” the differences between the sexes.

We encourage you to be skeptical when you read popular articles naming testosterone as the source of all lust and aggression or explaining that postmenopausal women feel less “womanly” because of declining estrogen levels. The study of hormones is a young science, and new research is constantly overturning previous theories. There is so much more to sexual desire than chemistry—body image, self-esteem, health, relationship status, and access to resources such as information, time, space, and privacy all play a far bigger role in your enjoyment of sex than hormones alone.

That said, estrogen, progesterone, and testosterone do have physiological effects that will impact your sex life and that are well worth learning to identify. If you have never noticed these effects, don’t be alarmed; some people are simply more responsive to hormonal fluctuations than others.

ESTROGEN AND PROGESTERONE: The most influential form of estrogen is estrodiol, which a woman produces in her ovaries during the first half of the menstrual cycle throughout her reproductive years. Estrogen promotes blood flow throughout the body (including the genitals), vaginal lubrication, a general sense of well-being and energy, and greater physical and emotional sensitivity. Progesterone, which a woman produces in her ovaries during the second half of the menstrual cycle, blocks the effects of estrogen, suppresses the immune system, and sedates the central nervous system. Some women experience progesterone as soothing and relaxing, others as fatiguing and depressing.

If you’re not on birth control pills, you may have noticed an increase in libido midcycle (right before ovulation) when your estrogen levels are highest, or right before menstruation, when progesterone levels drop.

Desire has definitely changed for me! I’ve noticed as I’ve gotten older, my level of horniness rises in response to ovulation. Some months, I’m ready to jump on anyone!

I’m finding that in the last year or so, I have marked monthly fluctuations in desire and responsiveness. Ten days of the month, I think of little but sex, and have incredible orgasms. The rest of the month is more ordinary.

If you are on birth control pills, you may have noticed that your libido sags for most of the month, but rebounds during the week you’re off hormones. Birth control pills contain just enough estrogen to prevent breakthrough bleeding, along with the high quantities of progesterone necessary to short-circuit ovulation and implantation. Progesterone is responsible for most of the Pill’s negative side effects: bloating, headaches, depression, and reduced desire.

Most of my lifetime I have been on birth control or other medications that altered my ability to “want” to have intercourse. Seems like I’m most aroused during my periods and while pregnant.

I found that birth control pills really did a number on arousal for me. And of course, if I couldn’t get aroused, I didn’t want sex as often…it was a nasty cycle.

The Pill killed my sex drive. Who knew? I went on it when I was 17 because of a broken condom and stayed on it till I was 25, when I went off it because I was no longer in a monogamous heterosexual relationship and kind of wondered what my hormones would be like without it. Best damn decision I ever made. I’m not suicidally depressed anymore. I have a libido! For a few months after I went off the Pill things became ridiculous: I’d have one day a month where I wouldn’t get any work done because I’d just sit and clutch the arms of my chair and fantasize. I’d know my period was coming because I’d find myself looking at people I normally didn’t find at all attractive and becoming mesmerized by the way the little hairs on their cheek caught the light.

Other progesterone-based birth control methods, such as Norplant implants and Depo-Provera shots, can be equally hard on your libido. However, individual responses to hormones vary greatly. Plenty of women experience no negative effects from progesterone, while others report increased desire while on birth control. Certainly, freedom from the fear of unwanted pregnancy can be highly arousing in and of itself.

I got a Norplant shortly after starting to have sex, and it affected my sexual response in ways I didn’t notice until I got it removed. For me, those few extra hormones kicked me up from what appears to be a more or less average libido to a hair-trigger orgasm girl who wanted sex three times a day.

TESTOSTERONE: Women produce testosterone in their ovaries and adrenal glands. Men produce ten to twenty times as much in their testicles. Testosterone appears to play a significant role in sexual sensation for both men and women—from boosting libido to enhancing genital sensitivity to heightening orgasm.

Researchers have proposed that variations in sex drive are influenced by variations in testosterone levels: that some of us are naturally “high-T” individuals, while others are “low-T.” (To avoid charges of sexism, some researchers hasten to add that even though women have much lower levels of naturally occurring testosterone than men, they might compensate by having a higher sensitivity to testosterone.) On the other hand, most of us have had the experience of feeling “high-T” at some point in our lives (usually in the first flush of a new relationship) and decidedly “low-T” at others. Context can often trump chemistry.

Ebb and Flow

We all take for granted that “women have their cycles,” but desire and energy fluctuate for men and women alike—in daily, monthly, seasonal, and situational cycles. Some research suggests that testosterone levels in men peak in the morning and dip in the evening; they’ve also been found to increase in the autumn, and decrease during times of stress. We’d encourage you to explore your unique personal patterns and body rhythms so that you can make the most hay when your own sexual sun is shining:

I want sex more in the spring, summer, and fall, we’re at the nadir of my sex drive right now (late March). I also find I want sex more when I am happy or angry. When I am anxious or depressed, nope. No need for sex here. Not even masturbation. I really think, overall, each sexual relationship I have had has resulted in changes in my experience of desire and arousal. With each new person, new things turn me on and get me off.