Life rarely goes as planned—and your workouts are no exception. Whether a day of poor weather spurs you to hit the treadmill instead of the open road, or a bout of illness makes you opt for a restorative yoga class over a challenging lifting session, you have to roll with the punches. And recently, people have started syncing their exercise routines to a different piece of personal data: their menstrual cycles.
The of cycle syncing, or adjusting how you eat and exercise based on the phases of your menstrual cycle, was introduced by integrative nutritionist . More recently, it gained traction on TikTok as a method for optimizing your training. Users when they scheduled trying workouts during ovulation and restorative-based movements when menstruation began.
But how important is it to match your effort to your body’s ever-fluctuating hormone cycles? Does this mean opting out of a trail race or a once-in-a-lifetime backpacking trip just because your period started?
A Quick Refresher on the Menstrual Cycle
Your menstrual cycle has four phases, says , program director of the Gynecologic Health and Disease Branch at the National Institutes of Health (NIH). Those phases are menstruation, the follicular phase, ovulation, and the luteal phase.
The day your period begins is the first day of menstruation—and the start of a new cycle. Once “that time of the month” ends, your body moves into the follicular (preparing the egg for ovulation) phase, which happens about . The process concludes with the luteal phase, where a new egg begins the journey to your uterus.
The entire process typically lasts between However, those with conditions such as endometriosis, polycystic ovarian syndrome (PCOS), and thyroid disorders may experience that make it more difficult to track particular phases.
The Potential Benefits of Cycle Syncing
In order to practice cycle syncing, you need to understand how your hormones fluctuate throughout the month. For example, on the first day of your period—the beginning of your cycle—you start to experience a gradual increase in estrogen, that are key to your reproductive system, Tingen says.
Your estrogen levels peak right before ovulation, she says. Afterwards, you start to have a larger increase in , which becomes the dominant hormone until menstruation begins again.
The science behind the cycle syncing trend is still in the early stages—and more studies need to be done in order to evaluate the effectiveness of this approach. However, some research suggests that these changing hormone levels may make you more or less primed for rigorous, high-intensity exercise.
For example, a 2020 meta-analysis of past research on this topic found that exercise performance may diminish—albeit slightly—during the follicular phase, when estrogen and progesterone levels are low and your body is preparing for ovulation. However, it’s worth noting, as the study authors do, that when it comes to cycle syncing, this type of variation may only be applicable to athletes competing at the elite level.
Estrogen is a key component. A 2019 review article published in Frontier in Physiology cited the hormone’s ability to . However, the same research highlights how estrogen also decreases the stiffness of ligaments and connective tissue, making athletes more susceptible to injury. Progesterone counteracts the effects of estrogen, serving as a
What Does This Mean for You, Your Cycle, and Your Workouts?
Although cycle syncing doesn’t have much evidence on its side yet, there’s no harm in giving it a try if you want to work out with a little more intention, says Menstrual cycles are unique, highly-individual experiences. While one person may feel run-down and fatigued during their period, another may not. Giving it a shot is the only way to know which camp you’re in.
If you’re interested in trying cycle syncing, Tingen says you should track your body’s hormonal fluctuations for a few months (Remember that some period-tracking apps ) If you do that for three cycles, then you have a baseline for understanding how menstruation affects you and your training, Tingen explains.
Take notes on how you feel as the month continues. How did your energy shift? What types of movement felt great? Which ones felt “bleh”? Over time, you’ll glean a broader understanding of your body’s cycles—and that self-knowledge may just take your workouts to the next level.
Tingen says cycle syncing should never be about telling yourself that you “can’t” do something like a big hike or a long bike ride. Instead, it can give you important information about how to best support yourself during more demanding efforts. For example, Tingen says research shows that heavy periods may lead to low iron levels, which may cause you to . If you have strenuous workouts planned for that time period, you may want to consider eating high-iron foods like red meat, egg yolks, and leafy greens.
For some people, cycle syncing may be a helpful tool when it comes to performance; for others, it may not feel necessary.
“The culture is changing so much,” Tingen says. “Periods and menstruation used to be something taboo that we weren’t able to talk about, and now it’s something that I want women to feel empowered to know about themselves.”