Once you start working out regularly, you will be able to manage your weight better, and build muscle strength. Sometimes, you may also end up with sore muscles, especially if you workout after a long gap or exercise for too long. These are not the only changes your body may go through. It may have an impact on your menstrual cycle too. Losing weight or gaining it can lead to a missed period, which means your period does not happen during the expected time of the menstrual cycle. Too much exercise may cause a missed period as well!

What is a missed period?

For most women, menstruation occurs roughly every 28 days, though normal cycle lengths can range from 21 to 35 days, says obstetrician and gynaecologist Dr Sukirti Jain.

A missed period is defined as the absence of period bleeding during this regular cycle. There are various reasons for a missed period, including pregnancy, hormonal imbalances, stress, significant weight changes, and menopause. In addition to the absence of menstruation, you might also experience nausea, breast tenderness, fatigue, or changes in mood, especially if pregnancy is a potential cause.

How does exercise cause a missed period?

Exercising during period comes with a set of benefits, including relief from period cramps. But in general, doing too much exercise is one of the common causes of a missed or late period, according to the UK’s National Health Service.

During a 2014 study published in the Journal of Endocrinological Investigation, it was found that half of the women who exercise regularly experience minor menstrual disorders, including missed period. Another study, published in the BMJ in 2007, found that 44 percent of participants who exercised vigorously experienced a missed period.

Exercise can cause a missed period through several mechanisms related to how physical activity impacts the body’s hormonal and energy balance, says Dr Jain. Here’s how:

1. Energy deficit

Intense or excessive exercise can increase energy expenditure. If caloric intake does not match the energy output, the body may enter an energy deficit. To conserve energy, the body may prioritise essential functions and reduce less critical ones, such as reproductive functions. This energy conservation can lead to a decrease in the production of reproductive hormones, disrupting the menstrual cycle and potentially causing a missed period.

2. Hormonal disruption

The Hypothalamic-Pituitary-Ovarian (HPO) axis regulates menstrual cycles through hormonal signals, says the expert. Intense exercise can disrupt this hormonal axis, leading to reduced levels of estrogen and progesterone, which are crucial for maintaining a regular menstrual cycle. Disruption in hormone levels can result in irregular cycles or missed periods.

3. Leptin levels

Leptin is a hormone related to energy balance and appetite regulation. Intense exercise can lower leptin levels, which can affect menstrual function. Low leptin levels signal the body that it is in a state of low energy, which can impact reproductive hormones. Lower leptin levels can contribute to missed periods by signaling the body to reduce reproductive activity due to perceived low energy reserves.

4. Body fat and weight changes

Excessive exercise often leads to lower body fat levels. Body fat is crucial for estrogen production, and very low body fat can lead to decreased estrogen levels. Low body fat can result in a lack of estrogen production, which is necessary for the regular shedding of the uterine lining, leading to missed periods.

5. Stress response

Intense physical activity can increase cortisol levels, a stress hormone. Elevated cortisol levels can impact reproductive hormones and menstrual regularity. Chronic stress from excessive exercise can lead to hormonal imbalances that disrupt the menstrual cycle.

6. Physical stress

The physical stress from intense or prolonged exercise can impact overall health and hormonal balance. The body may react to this stress by altering menstrual function. This stress response can lead to missed periods or irregular cycles as the body adjusts to the increased physical demands.

Activities like marathon running, competitive sports, or intense weight training are more likely to cause disruptions in menstrual cycles, says the expert. Exercise routines that exceed several hours per week at high intensity, especially if combined with inadequate caloric intake, can also increase the risk of missed periods.

What are the ways to prevent a missed period due to exercise?

To prevent missed periods due to exercise, consider the following tips:

1. Moderate exercise

Missing periods are more likely to happen with exercise routines exceeding 4 to 5 hours per week at high intensity, particularly if combined with inadequate caloric intake or significant weight loss. So, maintain a balanced exercise routine with moderate intensity and duration. Avoid excessive or overly intense workouts, says Dr Jain.

2. Adequate nutrition

Ensure sufficient caloric intake to meet the energy demands of your exercise routine. Include a balanced diet with adequate carbohydrates, proteins as well as fats. Also, stay well-hydrated to support overall health and hormonal balance.

3. Manage stress

Stress can also affect your menstrual cycle, so go for stress-reducing practices. You can do yoga, meditation, listen to music or you can simply take rest.

Too much exercise may cause a missed period, so balance exercise intensity and duration to avoid excessive physical stress. Ensure sufficient caloric intake and a balanced diet to meet the energy demands of your exercise routine and to avoid missed periods.