Benefits are greater

STARTING A programme of physical fitness is one the best lifestyle changes a woman can make. Exercise improves the quality of life significantly: heart and lung capacity increase; flexibility, strength and endurance improve; body fat decreases, bones become stronger, atherosclerosis, diabetes and other diseases become less common.

The one downside to exercise — especially intense exercise, is that menstrual disorders are more common in female athletes than in the general population.

To be fair, exercise actually reduces the pain of menstrual cramps, and it lessens the severity of symptoms linked to the premenstrual syndrome (PMS): breast tenderness, mood swings, appetite changes and fluid retention. Nevertheless, the lifestyle of a hard-training athlete can cause amenorrhoea — absence of menstruation. Most women think it is a good thing — an indicator of intense training, and some are simply grateful for its absence.

But prolonged exercise-induced amenorrhoea is associated with oestrogen deficiency and can cause osteoporosis — loss of bone density. This lack of oestrogen is especially catastrophic in the teenage years when most of the skeletal bone mass is laid down and strengthened.

Oestrogen deficiency may also negate some of the anti-atherosclerotic and anti-cardiovascular disease effects of exercise.

Why intense exercise suppresses the normal menstrual cycle is unclear, and exercise-induced amenorrhoea is a diagnosis of exclusion arrived at after ruling out pregnancy, hormone disorders, pituitary tumours and a host of other syndromes and genetic defects.

Sports that emphasise a lean physique tend to be linked with this condition: running and gymnastics are more commonly associated with it than swimming. More than the exercise itself, sudden onset of intense exercise, poor nutrition, inadequate calorie intake, low body weight or a steep fall in body weight, abysmally low levels of body fat, and stress are the causes of this condition.

Maintaining a positive energy balance - i.e., consuming enough calories, is essential for maintaining ovulation.

Treating exercise-induced amenorrhoea promptly is important. The first step is to rule out other medical disorders that might interfere with the menstrual cycle.

Treatment includes a 5 per cent increase in body weight, slight lowering of exercise intensity, relaxation techniques for stress, good nutrition, calcium supplements and sleep. If these measures fail, oestrogen and progesterone pills are the next line of treatment.

Remember: the benefits of exercise at all ages far outweigh the risks associated with it. If your exercise programme causes menstrual dysfunction, consult your physician. Most likely, a few minor adjustments to your lifestyle will help get rid of it.