Managing the circadian rhythm—your internal twentyfour-hour clock that determines when you want to fall asleep and wake up;34
Trust and bonding via actions such as parenting, hugging, touching, and having orgasms—which is why it's called the “love hormone.”35
Because women can give birth, we have more oxytocin than men, and it works better for us. Oxytocin is amplified by estrogen and counteracted by testosterone, says Marianne J. Legato, MD, FACP, author of Why Men Never Remember and Women Never Forget and founder of Columbia's Partnership for Gender-Specific Medicine.36 That means that after sex, when you and your male partner both have a burst of loving oxytocin, you both want to cuddle and connect—at first. But testosterone counteracts the oxytocin, and the fact your sweetie might want to soon do something different, like check his e-mail, could have nothing to do with you.
Oxytocin has been used to induce labor, but more recently has been put into a nasal spray and marketed to helping with everything from autism and shyness to getting your man to share more in a relationship.37
Thyroid Hormone: The thyroid gland secretes a hormone that regulates metabolism, or how the body uses energy. Thyroid hormone affects a long list of items, including weight, body temperature, breathing, muscle strength, skin dryness, menstrual cycles, brain development, cholesterol levels, and heart and nervous-system functions. Just about every organ in your body can be affected by this one-ounce gland, shaped like a butterfly, that's located in the lower part of your neck.
Because of pregnancy, aging, and autoimmune disease, women's thyroids often get out of sync, sometimes producing too much thyroid hormone and, more often, too little. It can be hard to distinguish symptoms of thyroid problems from other concerns—such as depression, menopause, and fibromyalgia—and thyroid issues can make these concerns worse.
If you are hyperthyroid, with too much thyroid hormone, you may have some of these signs and symptoms:
Nervousness, anxiety, irritability, and/or panic disorder;
Increased perspiration and/or heat intolerance;
Racing heart and palpitations (irregular heartbeats);
Thinning skin and/or hair;
Muscular weakness, especially in the upper arms and thighs;
Shaky hands;
Staring gaze;
Insomnia and/or fatigue;
More frequent bowel movements;
Weight loss despite a good appetite;
Lighter menstrual flow and/or less frequent menstrual periods.
Hyperthyroidism and one of its causes, Graves' disease (an autoimmune thyroid illness38), affect eight times as many women than men. Treatment depends on the cause of the hyperthyroidism and ranges from no treatment to antithyroid medication to radioactive iodine.
If you are hypothyroid, with too little thyroid hormone, you may have these signs and symptoms:
Fatigue, from feeling run down to exhaustion;
Difficulty concentrating, brain fog;
Depression, anxiety, and/or difficulty sleeping;
Unexplained or excessive weight gain and appetite change;
Dry, coarse, and/or itchy skin;
Dry, coarse, and/or thinning hair;
Feeling cold, especially in the extremities;
Constipation;
Heart palpitations;
Muscle and joint pain;
Infertility and/or miscarriages;
Increased menstrual flow and more frequent periods.39
Like Graves' disease, Hashimoto's thyroiditis, an autoimmune disease that causes hypothyroidism, is also more common in women than in men; it affects roughly seven women for every one man.40Thyroidhormone-replacement drugs are used for treatment of hypothyroidism. Many women who have suffered from thyroid problems notice a huge difference in their symptoms when they've recovered from thyroid-hormone imbalance.
Estrogen and other hormones can interact with thyroid hormone, making women more susceptible to thyroid problems—especially hypothyroidism—during and after pregnancy and during menopause.41
Pregnant moms need to have enough thyroid during pregnancy, especially during the first ten to twelve weeks, to help the baby's brain development, says endocrinologist Dr. Gunjan Tykodi.42
Melatonin: You may have heard of melatonin if you have sleep problems, because this hormone maintains the body's circadian rhythm, and regulates sleepiness, wakefulness, and body temperature. But melatonin has other critical functions. This hormone, secreted by the pineal gland in the middle of your head, also helps regulate other hormones and determines when teen girls start to menstruate, the frequency and duration of menstrual cycles, and the timing of menopause.
It also has strong antioxidant effects and may strengthen the immune system. Some think melatonin levels may be associated with breast-cancer risk, since women with breast cancer tend to have lower levels of melatonin.
What do you get your melatonin from? Darkness. Your pineal gland pumps out more melatonin when it's dark and stops producing the hormone when it's light. If you turn on the bathroom light in the middle of the night, you prompt your pineal to produce less melatonin, which is why you could have a harder time falling back asleep when you return to bed. Exposure to bright lights in the evening (when you work on the computer or watch TV late at night) or too little light during the day (when you're doing shift work or have jet lag) can disrupt the body's normal melatonin cycles. You might try software programs such as Flux and color filters to make computer screens more night friendly.43
Researchers believe melatonin levels drop as we age, which could be why some older adults have sleep problems. This change in levels could be why older adults tend to go to bed and wake up early.44
To increase your nightly melatonin, start with a melatoninfriendly lifestyle: use dusk and dawn as reminders to go to bed and wake up, make sure the bedroom is dark, and keep a dim light in the bathroom at night.
Melatonin supplements—tablets, capsules, cream, and lozenges that dissolve under the tongue—may help with sleep problems associated with menopause. Check with your doctor, and keep the dose close to the amount that our bodies normally produce (less than 0.3 mg per day).45
Men, Women, and Illness
Women get sick more often than men. A survey of 3,000 people, conducted by Engage Mutual, a British insurance and financial company, found that women get sick an average of seven times a year and men an average of five times.46 There can be many reasons—stress, greater exposure to toxins, the vulnerability of pregnancy.