May 18, 2015
Is Working Out Causing Missed Periods?
June 1, 2015
Consistent exercise can induce many wonderful changes in the body—fat loss, increased muscle mass, decreased blood pressure, improved metabolism, etc. But there are certain changes that aren’t so welcome. In fact, vigorous athletic training can disrupt a woman’s menstrual cycle—what’s known as ‘amenorrhea’, or ‘exercise-induced amenorrhea’. This is more common than you might think, but just as with any condition that disrupts the body’s homeostasis (the natural balance), it’s important to educate yourself and learn what causes amenorrhea, what the risks are, and how to treat it.
What is Exercise-Induced Amenorrhea?
In its simplest terms, amenorrhea is the medical term for the absence of menstruation (the monthly period). Primary amenorrhea, as described by sports nutritionist Emily Brown, “is diagnosed when a young woman fails to reach menarche [the first occurrence of menstruation] by an expected age or by the time other changes associated with puberty have occurred.” Secondary amenorrhea refers to when a woman who has begun regular menstruation stops having a regular period for three or more consecutive cycles (90 days). When these imbalances come about through sport and athletic training, it is known as exercise-induced amenorrhea.
What causes it?
Some studies have put the incidence of amenorrhea at up to 60% of female athletes. Now, having a regular menstrual cycle is a sign that a woman’s body is operating normally—but the female reproductive system is highly sensitive, and there are a lot of hormones at work during menstruation that can be disrupted through internal and external influences, including:
-Intense physical training and athletic competition
-Physical and mental stressors
Brown comments that traditional thinking tied the disruption in menstruation to a drop in a woman’s body fat levels (below a healthy percentage). As such, sports that traditionally feature athletes with low body weight—such as running and cycling—have been considered potential triggers for exercise-induced amenorrhea. However, Brown writes that more recent research has identified low-energy availability—regardless of body weight or fat—as the main cause of amenorrhea.
Your energy availability is the amount of energy you have left following dietary intake (i.e. energy from the food you eat) and the energy spent during a workout. The leftover energy is used to power less important jobs in the body (relatively speaking), such as cellular maintenance and reproduction. However, the female body requires a good amount of energy to ensure the normal secretion of hormones such as estrogen (which helps regulate the menstrual cycle). If there isn’t enough energy to do that, then menstruation can be interrupted.
Now, the reason body weight/fat is no longer considered to be the main trigger for amenorrhea is because a female athlete can maintain body weight levels during instances of low energy availability. When there is an insufficient balance between the amount of energy you expend during exercise and what you gain from nutritional intake, the body will compensate and start shutting down certain systems that are not essential for ‘survival’. This includes lowering metabolism levels and energy usage in cellular reproduction, as well as the reproductive system (as mentioned above). Obviously, the body recognizes that it is not in an ideal state to carry a pregnancy, which is why the energy supply to the reproductive system is impacted (seeing as it is not considered as a ‘vital’ system at that point in time).
Despite all of this, there are still instances where women who train hard and eat enough to maintain positive energy availability still develop amenorrhea. This is due to the release of stress hormones during exercise (such as beta-endorphins and catecholamines). High levels of these hormones can negatively impact the brain’s production of reproductive hormones (such as estrogen and progestogen), thus disrupting menstruation and causing amenorrhea. Of course, mental stress from sources other than exercise and CrossFit can also trigger a high release of such hormones.
Complications from Exercise-Induced Amenorrhea
One of the most serious problems that can arise from exercise-induced amenorrhea is a deficiency of estrogen. Estrogen is a vital hormone for women, and too little of it can lead to infertility, atrophy of the breasts and vagina, and the degradation of bone tissue (osteoporosis). Low estrogen levels cause the body to ‘draw’ calcium from the bone in order to maintain adequate levels of the mineral in the blood, which is important for the body to be able to continually perform physiological tasks. However, the longer amenorrhea is prolonged, the more calcium is leeched—increasing the risk of stress fractures in the spine and hip as well as osteoporosis (a condition in which bones become weak and brittle). What’s really scary is that a significant loss in bone mineral density may not be reversible. Brown notes that the risk for stress fracture is two to four times greater in amenorrheic athletes compared to athletes with normal menstrual cycles.
In addition, amenorrhea also affects heart health, once again due to the deficiency of estrogen. A lack of the hormone impairs proper blood vessel dilation, comprising exercise capacity and the function of the heart. This can lead to atherosclerosis, cardiovascular disease and even heart attacks in older athletes.
Diagnosis and Treatment
Because there are several potential causes for amenorrhea, treatment needs to be tailored to the specific athlete in question. Before starting any treatment, women suffering from exercise-induced amenorrhea should consult with their doctor to ensure there are no other causes for an interruption to their menstrual cycle. This could include pregnancy, premature menopause, and thyroid dysfunction.
Once the cause is confirmed, the appropriate treatment should target said cause. For example, an athlete with an eating disorder requires far more intensive psychological therapy than one who is working out too often without adequate rest. The main objective of all treatment is to restore estrogen levels to a normal range. For most women, this can be achieved by increasing caloric intake and reducing exercise frequency and/or intensity. Brown refers to a 2002 study on amenorrhea, which suggests “taking one rest day per week with no exercise and increasing caloric intake by 200-300 calories per day…In addition, increasing the intake of calcium, vitamin D, iron, zinc, and the B vitamins should help correct any nutrient deficiencies that may have developed. Aim to achieve a calcium intake of 1500 mg/d and a vitamin D intake of 600-800 IU/d through diet or supplements.”