Exercise‑Induced Amenorrhea: How to Balance Training and Menstrual Health

When a dedicated athlete suddenly stops getting her period, panic can set in. The missing flow isn’t just an inconvenience-it can signal deeper hormonal shifts that affect bone strength, fertility, and overall wellbeing. Understanding why amenorrhea happens in the context of training, and learning how to restore balance, empowers women to stay fit without compromising health.

What is Amenorrhea?

Amenorrhea is a medical condition where a woman experiences an absence of menstrual periods for three or more consecutive months. It can be primary (never having had a period) or secondary (stopping after having regular cycles). In athletes, the most common form is functional hypothalamic amenorrhea, triggered by a mismatch between energy intake and expenditure.

Why Exercise Can Disrupt the Menstrual Cycle

Exercise is a physical activity that raises energy demands. When the body doesn’t receive enough calories to cover this demand, it perceives a state of stress.

The brain’s hypothalamus, which regulates reproductive hormones, can shut down its signaling to conserve energy. This chain reaction lowers luteinizing hormone (LH) and follicle‑stimulating hormone (FSH), ultimately halting ovulation and periods.

The Female Athlete Triad Explained

Female Athlete Triad is a three‑part syndrome linking low energy availability, menstrual dysfunction, and reduced bone mineral density. While the Triad originally described elite athletes, its principles apply to anyone who trains intensely while restricting food.

• Low Energy Availability: Not enough calories to support both exercise and basic bodily functions.
• Menstrual Dysfunction: Ranges from irregular periods to complete amenorrhea.
• Bone Health Impairment: Decreased estrogen leads to weaker bones and higher fracture risk.

Recognizing the triad early can prevent long‑term damage.

Key Hormonal Players

Estrogen is the hormone most affected by disrupted cycles. It supports bone remodeling, cardiovascular health, and mood regulation. When estrogen drops, athletes may notice joint pain, decreased stamina, and mood swings.

Progesterone follows ovulation and helps prepare the uterine lining. Low progesterone can cause sleep disturbances and anxiety.

Other hormones-cortisol, leptin, and thyroid hormones-also shift during energy deficits, compounding the problem.

Assessing Energy Availability

Energy Availability (EA) is the amount of dietary energy left for bodily functions after accounting for exercise calories. It’s calculated as:

1. Determine total daily caloric intake (food + drinks).
2. Subtract calories burned during exercise.
3. Divide the remainder by lean body mass (kg). The result is EA in kcal·kg⁻¹·day⁻¹.

Values below 30kcal·kg⁻¹·day⁻¹ are considered low and linked to menstrual disturbances.

Nutrition Strategies to Restore Balance

Nutrition isn’t just about eating more-it's about eating smarter. Aim for a balanced mix of carbohydrates, proteins, and healthy fats while meeting micronutrient needs.

• Carbohydrates: Provide the primary fuel for high‑intensity training. Aim for 5-7g per kilogram of body weight daily.
• Protein: Supports muscle repair and hormone synthesis. 1.2-1.7g per kilogram is typical for active women.
• Fats: Essential for estrogen production. Include omega‑3 sources like salmon, flaxseed, and walnuts.
• Micronutrients: Calcium (1,200mg) and vitamin D (800-1,000IU) protect bone health. Iron is crucial to prevent anemia, especially in menstruating athletes.

Gradually increasing calorie intake by 300-500kcal per day often re‑establishes normal cycles within 3-6 months.

Training Adjustments that Help

Overtraining is a common trigger for amenorrhea. Reducing volume, intensity, or frequency can lower physiological stress.

• Incorporate at least one full rest day per week.
• Swap one high‑impact session for low‑impact cross‑training (e.g., swimming or yoga).
• Periodize your program: cycle through phases of building, peaking, and recovery.

Monitoring tools like heart‑rate variability (HRV) can flag when the autonomic nervous system is overstressed.

When to Seek Professional Help

If periods remain absent for more than six months despite dietary and training changes, consult a healthcare professional. A sports‑medicine physician or an endocrinologist can run blood tests for hormone panels, bone density scans, and assess for underlying conditions like polycystic ovary syndrome (PCOS) or thyroid disorders.

Comparison of Common Exercise‑Related Menstrual Issues

Practical Checklist for Athletes Experiencing Amenorrhea

• Track menstrual dates using a simple calendar or app.
• Calculate current Energy Availability; aim for >30kcal·kg⁻¹·day⁻¹.
• Increase daily calories by 300-500kcal, focusing on carbs and healthy fats.
• Ensure adequate calcium (1,200mg) and vitamin D (800IU) intake.
• Schedule at least one complete rest day each week.
• Monitor resting heart rate and HRV; spikes may indicate overload.
• Visit a sports‑medicine clinician if periods don’t return after 3months.

Long‑Term Outlook

Restoring a regular cycle is usually a sign that hormonal balance is returning. Over time, bone density improves, and fertility potential rebounds. Maintaining the habits that helped-adequate fuel, balanced training, and stress management-keeps the risk of recurrence low.