Cortisol and Sex Drive
Holly and Alan were happily married young newlyweds with a big problem. As newlyweds, one of the things that should have held great interest for them (SEX!) offered little allure. The problem was certainly not their love and attraction for each other, but their extreme stress levels. Both Holly and Alan were (and still are) ambitious young professionals, with long stressful hours at the office and all the trappings of financial success; both had MBAs, drove BMWs, and lived in a beautiful home paid for by two sizable incomes. The good news is that Holly and Alan were able to reignite the spark in their love life. Learn how they did so in Chapter 8.
You don't need to read a book about the relationship between stress and disease to know that when we're stressed out we also have problems in the "intimacy" department. For starters, menstrual cycles get all out of whack, erections are more difficult to achieve and maintain, and overall libido (sex drive) plummets. Stress simply makes us lose interest in sex. In males, this is due primarily to a dramatic fall in testosterone levels during stressful times. In females, the stress-induced loss of sex drive is a bit more complicated, involving disruption in levels not only of testosterone, but also of estrogen, progesterone, and prolactin.
The stress/libido relationship is, predictably, tied to cortisol levels (and also to another class of chemicals from the brain—the endorphins—but more on them later). In men, elevated cortisol levels do at least a few things to suppress our sex drive. First, cortisol signals the body to reduce its production of the "prehormone" compounds that serve as the precursors to testosterone. Cut off the supply of "parts" and your production of the end product also dries up. Next, just in case any testosterone does get produced, cortisol also blocks the normal response of the testicles to testosterone, which is generally to make guys feel frisky. This also means that supplemental forms of testosterone, such as anabolic steroids and dietary supplements containing DHEA or androstenedione, are less likely to have any effects on libido when you're under stress. Finally, if we think for a moment about the actual mechanics of achieving an erection, it is obvious that we need a redistribution of blood flow from one place to another. When you're under stress, however, blood is being channeled to places where it can provide the most benefit, like your arms for fighting or your legs for fleeing, not to your privates. Let's get back to the endorphins. These are the "feel-good," pain-relieving chemicals released by the brain, and they are responsible for the euphoric feeling known as "runner's high." The interesting thing about endorphins is that they also work to suppress some of the hormonal steps leading to testosterone production. This helps to explain the findings from studies of extreme endurance athletes wherein high levels of endorphins and cortisol are associated with low testosterone levels, reduced sperm counts, and reduced sex drive. This is not to say that aerobic exercise, such as jogging or cycling, is bad for you, but it emphasizes the fact that extremes of exercise (and inadequate recovery) are perceived by the body as stressors—and, in reaction, the body goes through the same stress response caused by other stressful events.
In women, the relationship between stress and sexual/reproductive function is a bit more complicated. In very basic terms, the menstrual cycle can be divided into two distinct phases. In the first phase, known as the follicular phase, estrogen is the dominant hormone (although there are several important hormones interacting here) and ovulation (release of an egg from the ovaries) is the primary event. The second phase of the menstrual cycle, known as the luteal phase, is dominated by an increase in another hormone, progesterone, which stimulates the uterus to get ready for implantation of a fertilized egg (assuming that the newly released egg meets up with an eligible sperm). Failing fertilization, the thickened uterine lining is lost in the form of blood and tissue during menstruation, and the whole cycle repeats itself in another twenty-eight days (give or take a couple days).
During stress, this extremely complex and tightly regulated hormonal balance gets all out of whack. Estrogen and progesterone levels drop (so eggs are not released from the ovaries, a condition called anovulation), and the uterine lining remains undeveloped (so eggs cannot be implanted). Menstrual cycles can become irregular (oligomenorrhea) or cease altogether (amenorrhea). Speaking of amenorrhea, it is interesting to note that female athletes often encounter disruptions in their menstrual cycles as a result of their training and eating patterns. Just as with the male endurance athletes (and their low testosterone levels) mentioned above, these female athletes tend to have low levels of estrogen and progesterone as well as a severely reduced libido. They also tend to be dieting or at least not consuming enough calories to support the energy demands of their sport. If you think about it, the fact that they have no interest in sex (or the ability to get pregnant) makes perfect sense. The change in hormone levels and the demands of their diet and exercise regimens are being perceived by the body as major stressors. Because the average pregnancy costs about fifty thousand calories (and afterward another thousand calories per day for breast-feeding), it is quite logical for the body to shut off sexual desire (and ability) during stressful times.
So what to do? Quit your job, move to the islands, and open a surf shop! Your sex drive is guaranteed to increase. (Ever wonder why you feel friskier when you're on vacation? Less stress!) Not practical to move your family to Tahiti? Okay, then at least do something about your cortisol levels. Solutions are presented in coming chapters.