Although many people think of weightlifting as a traditional male activity, women and individuals of all ages can benefit from regular strengthening exercises, such as lifting free weights or using resistance machines. However, excessive exercise, including weightlifting, can affect the production of hormones that regulate the female reproductive cycle, often resulting in irregular menstrual periods.
The average menstrual cycle lasts approximately 28 days, although many women experience regular cycles that last between 24 and 34 days. The flow of menstrual fluid lasts an average of four to seven days and generally occurs at the same time during each cycle. Irregular vaginal bleeding refers to spotting or bleeding between periods, bleeding after sex, cycles that occur more than 35 days apart and bleeding that lasts for more than seven days.
Weightlifting is one method of exercise that focuses on building strength and increasing muscle tone. A regular weightlifting routine plays an important role in reversing the normal decline in muscle mass as you age. It also helps women manage their weight and increase bone density, an important factor in preventing osteoporosis. However, rigorous exercise is a common cause of menstrual cycle irregularities. A low percentage of body fat and a high-energy expenditure in women weightlifters are contributing factors in irregular periods. Some women athletes stop menstruating altogether.
MayoClinic.com recommends participating in 20- to 30-minute weightlifting sessions two to three times per week. By performing single sets of 12 repetitions, women can build muscles efficiently. The amount of weight to provide optimal results should be heavy enough to cause muscle fatigue after approximately 12 to 15 repetitions. While some women athletes may prefer more intense workout regimens, changes in menstrual cycles may result. Gradually cutting back on a strenuous workout program can help your periods return to normal.
Irregular periods have a number of causes besides excessive exercise. Common causes of menstrual changes include pregnancy, breastfeeding and stress. Certain types of medication, such as oral corticosteroids, antidepressants, antipsychotics and some chemotherapy drugs may disrupt normal menstrual cycles. Since some conditions require medical treatment, contact your doctor if you experience menstrual irregularities. Medical exams and tests can help rule out serous causes of irregularity, such as pituitary tumors and thyroid disorders.