As a health writer, I tend to read about a lot of different health studies. Occasionally I read about a new study and think, "Really, you needed to do a study to find that out?" When I came across an article on NBC News entitled, "Stress is no good for your sex life, study suggests," it was one of those moments. Really? You needed to do a study to tell you what probably every adult on the planet could have told you?
The Study Results
The study included only women, who were divided into two groups - those with high-stress and those with average stress levels. The women were then shown an erotic video and there sexual reactions were recorded. According to the study women in the high-stress group had lower levels of genital arousal and showed more distraction during the video. They also had higher levels of the stress hormone, cortisol.
The researchers hypothesize that the higher levels of cortisol actually reduce your body's reaction to sexual stimuli. It seems while your mind is filled with all of the problems of the day or worry about future problems, your cortisol levels become elevated and these hormones turn off your sexual arousal buttons. It isn't news that stress makes you less in the mood, but, the study does show that it is an actual physical reaction to stress that causes you to be less turned on - it isn't just all in your mind.
Sex as a Stress Reliever
The paradox here is that sex can also help reduce stress. Having sex releases hormones - oxycontin and endorphins - called the "feel good" hormones. It makes you more relaxed and helps you feel more connected to your partner, all leading to less stress. But, if you are stressed and not feeling sexual, it's hard to "get in the mood."
Dr. Laurie B. Mintz suggests that you don't have to wait for desire to take over in order to enjoy a night of sex. Instead, you can "reverse the equation," and "Don't wait to be horny to have sex, instead, have sex to get horny." 
But, how do you do that? Dr. Mintz suggests planning your sex life. Because every couple is different, think about the ideal sexual frequency for you - once a week? twice? every other night? Once you and your partner decide what is right for you - plan your schedule to include sex. You might choose every Wednesday and Saturday night (or you might prefer mornings). Now you can prepare - think about your next sexual encounter throughout the day, make sure the kids are in bed or out of the house. Let your partner know how much you are looking forward to your "date," by leaving a sexy note on his pillow, sending a text message (make sure it isn't going to be seen by anyone else), or use other personal communications that both of you understand. Build up the anticipation.
You might think that there is something wrong with planned sex, but, many women simply aren't spontaneously aroused outside of being in a "new relationship." In the book, Principles and Practice of Sex Therapy, edited by Sandra Leiblum, Dr. Rosemary Basson states, "Understanding that spontaneous sexual desire is a reality for only some women, most notable when there is a new partner...would cause an unknown percentage of women concerned about their lack of spontaneous sexual desire to perceive their experience as normal."  Unfortunately, many women believe that they are the only ones who aren't spontaneously aroused - they believe there is something wrong with them.
Yoga - regular yoga may help to increase sexual arousal and lubrication. As with other exercises, it reduces stress and increases blood flow
Start with something non-sexual but intimate - Ask your partner for a massage or cuddle together. Starting with something non-sexual may be all you need to get yourself into the mood. The intimacy of the act helps fuel your feelings of connection which in turn can help you feel aroused.
Practice mindfulness - Focus completely on what is going on, how your partner smells, the touch of his hand, the feel of his skin. Immerse yourself in the experience. Focusing completely may just change you from not interested to interested.
While you don't want to get into the habit of "duty sex" sometimes you just need to go ahead and do it and know that desire will follow. While you may not want it when you start - once you get going desire kicks in.
 "Don't Wait for Desire: Reverse the Equation," 2013, Laurie B. Mintz, Ph.D., Psychology Today
 Leiblum, Sandra R (editor), Principles & Practice of Sex Therapy, 2006, Guilford Press, NY
"Stress Is no Good for your Sex Life, Study Suggests," 2013, Nov. 25, Anna Davles, Prevention Magazine, NBCNews.com