Understanding Cycle Syncing

“Cycle syncing” — adjusting your workouts, diet, or lifestyle based on where you are in your menstrual cycle — has become a major trend on social media. Influencers and wellness enthusiasts claim it helps with everything from building muscle to balancing hormones.

However, new research suggests the benefits may not be as significant as many think.

A study recently published in The Journal of Physiology found that timing your workouts to your menstrual cycle phases doesn’t significantly impact muscle growth.

What the Study Found

The study, led by researcher Lauren Colenso-Semple at McMaster University, involved 12 healthy women aged 18 to 30 with regular menstrual cycles and no recent hormonal contraceptive use.

Participants performed knee extension exercises with one leg during the late follicular phase (when estrogen levels peak) and with the other leg during the mid-luteal phase (when progesterone is dominant).

To measure how muscles built or broke down protein, researchers tracked:

  • Muscle protein synthesis (MPS): How the body builds muscle.

  • Myofibrillar protein breakdown (MPB): How much muscle protein is lost.

They used deuterium oxide (heavy water) to track amino acid use and collected saliva, blood, and muscle samples.

The results? Exercise boosted muscle-building activity overall — but the menstrual phase didn’t change the results.

In short:

“Women can reap the benefits of lifting weights at any point during the cycle,” Colenso-Semple explained.

Why the Findings Matter

This study challenges the popular belief that training during certain menstrual phases yields better strength or muscle results.

OB/GYN Dr. Amy Banulis from Kaiser Permanente said the findings support what many experts already suspected:

“Hormones do not dictate strength gains.”

It also underscores how little has been studied about female physiology and exercise. For decades, most exercise research has focused on men, largely due to concerns that female hormonal cycles could complicate results.

According to Dr. Hugh Taylor, chair of Obstetrics and Gynecology at Yale New Haven Hospital:

“This study helps fill a gap in understanding how women’s hormones affect performance and recovery.”

The Limitations

Despite its valuable insights, the study was small, with just 12 participants, making it hard to generalize the results.

Researchers also focused on short-term muscle protein changes, not on long-term performance, endurance, or recovery.

Future research could explore:

  • How hormonal changes affect fatigue, injury risk, or metabolism

  • Whether birth control or perimenopause influence training outcomes

  • How different types of workouts (e.g., HIIT vs. yoga) interact with hormonal fluctuations

Hormones and How You Feel During Each Phase

Even though syncing workouts for muscle gain might not matter, hormonal changes throughout your cycle still influence energy, mood, and motivation.

Follicular Phase (Day 1–14)

  • Estrogen rises, often leading to higher energy and endurance.

  • You may feel stronger, more focused, and ready for intense workouts like HIIT or strength training.

Ovulation (Around Day 14)

  • Estrogen peaks, and some people report feeling their most powerful or energetic.

  • Great time for heavy lifting or cardio sessions.

Luteal Phase (Day 15–28)

  • Progesterone increases, which can raise body temperature and make you feel more fatigued.

  • Some people experience bloating, mood swings, or cramps.

  • Gentle exercise like pilates, walking, or yoga may feel better.

Menstrual Phase (Period)

  • Both estrogen and progesterone drop, which can lead to low energy.

  • It’s perfectly fine to rest, or opt for light stretching or low-impact workouts.

Why Listening to Your Body Matters

Every woman’s cycle—and how it affects her workouts—is different.

Some may feel energetic throughout the month, while others experience noticeable dips in strength or motivation before their period.

If your body feels off, forcing a high-intensity workout can increase fatigue or even risk injury. Instead, pay attention to your signals:

  • Feeling strong? Lift heavier.

  • Feeling sluggish? Try low-impact movement or rest.

  • Experiencing cramps? Gentle stretching or walking can help release endorphins and ease pain.

As Dr. Banulis advises:

“You don’t need to follow a strict cycle-based routine. Focus on what feels right for your body and ensure proper recovery.”

Benefits of Staying Active Throughout Your Cycle

Regardless of when or how intensely you work out, staying active offers consistent benefits across your menstrual cycle:

  • Improves mood and reduces anxiety

  • Eases PMS and cramps

  • Supports hormone balance

  • Increases blood circulation and reduces bloating

  • Boosts energy and sleep quality

Even a 20–30 minute walk or gentle yoga session can make a difference.

A Quick Review

The latest research shows that syncing workouts with menstrual phases doesn’t significantly impact muscle growth. You can train effectively at any point in your cycle.

However, hormonal shifts do affect how you feel—your energy, motivation, and comfort. Adjust your workouts accordingly, not based on strict rules but on listening to your body.

Ultimately, the best workout schedule is the one that supports consistency, recovery, and overall well-being.