Exercise as it relates to Disease/The menstrual cycle in response to physical exercise in the female athlete

Prevalence
Evidence has found strong relationships between menstrual irregularity (amenorrhea) and athletic participation. According to the NHS (National Health Service), about 3% of females are affected. Of these 3%, athletes involved in competitive gymnastics, long-distance running and ballet are at risk.

What is menstrual irregularity (amenorrhea)
Menstrual irregularity, also known as amenorrhea, is the absence of menstrual periods in a woman’s reproductive age. A normal menstrual cycle is 28 days, where the woman’s body sheds the lining of the uterus, lasting from 3 to 5 days. Amenorrhea is one of the three components of the female athlete triad. The female athlete triad is defined as the combination of disordered eating, amenorrhea and osteoporosis.

Amenorrhea is divided into two types; Menstruation does not occur during puberty.
 * Primary Amenorrhea:

Menstruation has occurred but ceases during pregnancy or lactation.
 * Secondary Amenorrhea:

Causes of amenorrhea in response to physical activity
Women in competitive sporting put their bodies through physical and mental stress to perform their best. Female athletes cut down energy intake to loose or maintain body weight. By doing this the body becomes energy deficit; the body begins to conserve metabolic energy by slowing down the basal metabolic rate (BMR), altering normal hormonal levels that regulate the body. This leads to low levels of estrogen in the body that can cause:
 * Abnormal menstrual cycles
 * Cessation of menstrual cycles
 * Delayed onset of menarche after age 16, and
 * Luteal phase defects in an ovulatory cycle

Disordered eating may not be clinically significant, but combined with high-energy output leading to weight loss, there is a central suppression of reproductive function and metabolic rate. Other indicators of metabolic deficiency include low levels of triiodothyronine (T3), leptin and growth hormone as well as elevated cortisol and creatinine kinase, which are effects of strenuous exercise.

==Effects of amenorrhea on the body == Bone mineralisation is estrogen dependent and menstrual irregularity is associated with reduced bone mineral density. Bone density is increased during adolescence, achieving ~90% peak bone mass before the age of 20. This is a crucial time in bone building and any occurrence of poor calcium and vitamin D intake, poor nutritional balance and lack of available estrogen can affect bone mineral density. When this occurs, signs of poor bone health, such as stress fracture, osteopenia and in some cases, osteoporosis occurs. Women who participate in sports such as competitive gymnastics, long-distance running and ballet during adolescence increase the risk of these four cases happening, causing detrimental effects on their health later on in life.

Prevention/Treatments/Recommendations

 * Prevention and Treatment:

Early recognition of menstrual irregularities is imperative to stop long-term issues arising. The coach, physician and nutritionist of the athlete or affected individual can accomplish this through:
 * Risk factor assessment and screening questionnaires
 * Introducing/encouraging an appropriate diet
 * Moderating the frequency of exercise with energy intake and recovery
 * Increased education for athlete, parents and coaches

These four recommendations can result in the natural return of a regular menstrual cycle. Hormone replacement therapy should only be considered in extreme circumstances, early on when diagnosed, to prevent the loss of bone density.

Conclusion
A combination of the above and a collaborative effort amongst athlete, coach, parents and physicians is optimal for the recognition and prevention of amenorrhea. As well as this, the potentially life-threatening illness of the female athlete triad can be prevented.