Should You Keep Running During Your Period? Science Has the Answer

Introduction

“Can you run during your period?” This is a question every female runner will eventually ask. Traditional beliefs often advise “rest more and avoid strenuous exercise” during menstruation, but modern sports medicine research tells a completely different story. This article starts from the physiological mechanisms to help female runners in Taiwan make the best decision for themselves.

The Body’s Actual State During Menstruation

The menstrual phase (Day 1–5) is when both estrogen and progesterone are at their lowest points, and the body undergoes the following changes:

• Uterine contractions: Prostaglandins promote uterine contractions to shed the endometrium, which is the main cause of menstrual cramps
• Slightly reduced blood volume: Bleeding leads to iron loss, and hemoglobin may temporarily drop
• Basal body temperature returns to normal: It falls from the luteal phase peak, making heat dissipation easier than during the luteal phase
• Mildly elevated inflammatory response: Tissue repair is slightly slower

Importantly, these changes vary greatly from person to person. Some women experience almost no discomfort on the first day of their period, while others suffer from severe cramps, headaches, and gastrointestinal symptoms (prostaglandins also affect intestinal smooth muscle).

What the Scientific Research Says

Multiple studies (including a systematic review published in BJSM) point out that:

• Light to moderate aerobic exercise effectively relieves menstrual cramps: Exercise promotes endorphin secretion, inhibits prostaglandin activity, and reduces uterine cramping
• Exercise does not increase bleeding volume: Aerobic exercise does not affect the total amount of menstrual blood loss
• Cardiorespiratory function does not significantly decline during menstruation: Research findings on VO2max differences across menstrual cycle phases are inconsistent, but overall differences do not exceed individual variation ranges
• Running during menstruation does not increase infection risk: This is a common misconception; proper use of hygiene products allows for safe exercise

Easy Runs vs. High-Intensity Training

Menstruation does not completely prohibit running, but the type of training needs to be distinguished:

Recommended

• Zone 1–2 easy runs (30–45 minutes): Help relieve cramps, improve mood, and promote blood circulation
• Stretching and yoga: Cat-cow and child’s pose are especially helpful for lower back pain
• Light strength training: Upper body or core, avoiding excessive core loading

Adjust as Appropriate

Not Recommended

• Maximal-intensity intervals or race-pace training
• High-impact jumping movements (some studies show pelvic floor muscle contractile strength slightly decreases during menstruation)
• Prolonged training in hot, humid environments

Non-Pharmacological Strategies for Relieving Menstrual Cramps

• Apply heat to the abdomen for 10 minutes before running: Relaxes the uterine muscles and reduces cramping
• Supplement with Omega-3: EPA in fish oil inhibits prostaglandin synthesis; studies show 1–2g daily has some effect
• Reduce refined sugar and caffeine intake: May exacerbate the inflammatory response
• Stay hydrated: Blood volume slightly decreases during menstruation, and adequate hydration helps maintain exercise performance

Choosing Hygiene Products

Common options available in Taiwan:

• Menstrual cup/disc: Most stable during running with no leakage concerns; initial use requires 2–3 cycles to adapt
• Sport tampons: Good elasticity, suitable for large movements; recommended to change every 4–6 hours
• Period underwear: Use with a light panty liner; suitable for days 3–5 when flow is lighter

Practical Advice

• Listen to your body’s signals: No rule forces you to run in pain; rest is also part of training
• Record your menstrual status in your training log: Track continuously for 3 months to identify your personal patterns
• Inform your coach: A good coach should be able to flexibly adjust your training plan based on your menstrual cycle
• If menstrual cramps severely affect daily life, consult a gynecologist to rule out conditions such as endometriosis, rather than simply pushing through

Conclusion

Running during menstruation has no absolute right or wrong—only the choice that best fits your body’s current state. The scientific position is clear: light exercise is beneficial, while forcing high-intensity training is unnecessary. Changing “period = rest week” to “period = recovery week” is the smartest mindset shift for modern female runners.

Related Reading

• Special Considerations for Female Runners: Menstrual Cycle and Training Adjustments
• Menstrual Cycle Training Adjustments for Female Runners: Intensity Recommendations for Each Phase
• Hormonal Cycle Training for Female Road Runners: Intensity Recommendations for Each Menstrual Phase
• Menstrual Cycle and Training Planning: Physiological Characteristics and Workout Adjustment Strategies for Each Phase (Highly Individual, Not Absolute Rules)