The average American adult consumes 200 mg of caffeine per day, the equivalent of two 5 oz. cups of coffee, the FDA reports. For menstruating women, this level of caffeine can aggravate physical or emotional changes before the onset of your period. In even greater amounts, caffeine can cause changes to the length of your period and menstrual cycle. By avoiding caffeine before and during your period, you can prevent menstrual symptoms from worsening.
Menstrual Periods
A woman's average menstrual cycle lasts 28 to 30 days, the time from the first day of one period to your next period. Your monthly period, during which your body discards the lining of the uterus, is a part of your menstrual cycle. Periods most often last three to five days and can vary from light in blood flow, to moderate or heavy. In the United States, a girl usually gets her first period around age 12 and will likely continue to menstruate until around age 50, according to the U.S. Department of Health and Human Service's Office on Women's Health. During menstruation, you may experience cramping, breast soreness, mood swings, irritability, bloating, headaches and fatigue.
Effects of Caffeine
Caffeine stimulates the central nervous system and is found in coffee, tea, chocolate, soft drinks and some medications. As a stimulant, caffeine can make you feel more alert and awake but may also cause you to feel shaky, jittery, nervous and cause a temporary rise in blood pressure, insomnia, an irregular heart beat, dizziness and dehydration. In the one to two weeks leading up to your period, experts suggest avoiding caffeine as it can heighten symptoms of irritability and anxiety, and cause other mood and energy level changes associated with premenstrual syndrome, the MayoClinic.com advises. During your period, you should also avoid caffeine since it may constrict blood vessels and elevate muscle tension, leading to cramping, Feminist Women's Health Center recommends.
Cycle and Period Length
A study in the March 1999 issue of the "American Journal of Epidemiology" by Laura Fenster and colleagues found women who consumed more than 300 mg of caffeine each day were less likely to have a period eight days or longer. The researchers believe caffeine constricts uterine blood vessels, reducing blood flow and menstrual bleeding, shortening the length of your period. Additionally, the researchers found these women were twice as likely to have a shorter menstrual cycle, a cycle 24 days or shorter, compared to women who consumed no caffeine.
Premenstrual Syndrome
Scientific studies show women who consume caffeine are more likely to experience symptoms of premenstrual syndrome, also known as PMS. These symptoms may include swollen or tender breasts, bloating, fatigue, tension, irritability, mood swings, crying spells, anxiety, depression, joint or muscle pain, and headaches or backaches. Symptoms occur around the time of menstruation, often one to two weeks before your period begins.
A study by Annette Mackay and Heinke Bonnlander, reported in the September 1990 issue of the "American Journal of Public Health," found women who consumed up to 10 cups of caffeinated beverages, including tea, coffee and soda, were 1 1/2 times more likely to report at least one premenstrual symptom than women who consumed no caffeinated beverages. The link was even greater among women with severe PMS. Researchers found the more caffeinated beverages these women had each day, the greater the likelihood of having premenstrual symptoms.
References
- FDA; Medicines In My Home --- Caffeine and Your Body; 2007
- Office on Women's Health; Menstruation and The Menstrual Cycle; October 2009
- MayoClinic.com; Premenstrual Syndrome; December 2009
- Feminist Women's Health Center; Menstrual Cycles --- What Really Happens in Those 28 Days; January 2011
- "American Journal of Epidemiology"; Caffeine Consumption and Menstrual Function; Laura Fenster, et al.; March 1999
- "American Journal of Public Health"; Caffeine-Containing Beverages, Total Fluid Consumption and Premenstrual Syndrome; Annette Mackay, et al.; September 1990
