What TikTok Gets Wrong About Cycle-Synced Workouts

Even if they're not fitness pros, TikTokers often swear to have the answer to more effective workouts. Users have promoted the 12-3-20 treadmill workout for building cardio endurance and weighted hula hoop sessions for better core strength. Now, they're encouraging folks with periods to program their fitness routines around their menstrual cycles, dedicating certain phases to particular types of workouts. Proponents of the practice claim that it can improve workout performance and results, increase energy, and provide "hormone support."

But are cycle-synced workout programs really all they're cracked up to be? Here, three experts in the field break down the potential benefits and the limitations of cycle-synced workouts — and what to keep in mind if you're going to give them a try.

Put simply, cycle syncing your workouts involves planning exercise around your menstrual cycle. The idea is to adjust the type or intensity of your workouts based on the natural fluctuation of reproductive hormones (particularly estrogen and progesterone) throughout the month, says Marissa Baranauskas, PhD, an assistant professor of human physiology and nutrition at the University of Colorado, Colorado Springs.

For example, here's what the hormone changes in a 28-day menstrual cycle might look like. Keep in mind that many people do not have consistent 28-day cycles, so these timelines will differ from person to person and from cycle to cycle.

Your body has receptors for estrogen and progesterone in your reproductive organs, as well as in your skeletal muscle, blood vessels, airway lining, brain, and fat tissue, Baranauskas says. As such, researchers have begun to find evidence suggesting that a menstruating person may respond differently to exercise depending on the levels of these hormones circulating throughout their body. "Some researchers believe that syncing or timing specific workouts to occur during phases of the menstrual cycle — when these hormones are low or high — may lead to more optimal responses or adaptations to workout programs," she explains.

That's the concept is behind all the cycle-syncing workout plans and conversations on TikTok. As a result, most of the recommendations for cycle-synced workouts circulating on the internet prescribe a plan like this:

There is some initial research investigating the menstrual cycle's impact on performance and recovery, says Baranauskas. Just know that the research available is relatively small, and no definite conclusions can be made just yet.

During the early follicular phase (aka menstruation), when estrogen and progesterone are at their lowest, menstruators often report low-back pain, joint discomfort, and muscle cramps, which may be linked to an increase in inflammation, says Baranauskas. Due to these unpleasant symptoms, they may not feel as comfortable or capable of performing intense physical activity; a 2021 research review found that athletes perceive performance declines during this phase of the menstrual cycle, which are commonly attributed to menstrual symptoms.

Also during this time, menstruators may be more susceptible to exercise-induced muscle damage, which can lead to particularly sore muscles or even strength losses, according to a 2021 meta-analysis of 19 studies. "As such, it might be recommended to plan lower-intensity workouts (i.e., yoga, walking, easy-paced running, biking, or swimming, or doing bodyweight exercises/lifting lighter weights) or have more time to recover between moderate- to high-intensity workouts in the days just before and after bleeding," she notes.

During the mid- to late-follicular phase (after your period but before ovulation), you may have a greater ability to generate muscular force and power, and you might have a better mood state and more motivation to tackle high-intensity workouts, says Baranauskas. (FTR, research on the topic is mixed; some studies show no changes in strength throughout the menstrual cycle, while others have found impacts.) "Higher levels of estrogen seem to be protective against muscle damage, and it is possible that recovery from high-intensity workouts may be enhanced during this phase," she adds. Consequently, you may feel more comfortable and confident lifting heavy weights or running at your top speed, she notes.

In the mid-luteal phase (just before your period, when you might experience PMS), menstruators may be more likely to experience negative mood states, potentially due to progesterone's depressive effect on "feel-good" dopamine or on the excitability of particular brain centers, says Baranauskas. In turn, folks who menstruate may feel more fatigued before and during high-intensity exercise, she adds. "Some evidence also suggests endurance capacity may be enhanced during this phase due to differences in how we store and use different fuel sources during exercise," says Baranauskas. That's why lower-intensity, longer-duration workouts may feel more achievable during this phase of the menstrual cycle, she notes.

By programming your fitness routine with your menstrual cycle in mind, there's a chance you could see some improvements in your performance or motivation by choosing workouts that reflect your cycle's effects. This may be the case if you're particularly sensitive to changes in your hormone levels or experience more symptoms when estrogen or progesterone levels are steeply increasing or decreasing, says Baranauskas; however, some individuals may not feel any major differences in exercise performance throughout the menstrual cycle, she adds.

And despite the initial research on how the menstrual cycle affects exercise performance, there aren't any "scientifically proven" benefits of cycle syncing, says Alyssa Olenick, PhD, CISSN, CFL 1, an exercise physiologist and sports nutritionist. And there are plenty of potential limitations to the practice.

For one, not everyone has a 28-day menstrual cycle, which many cycle-synced workout plans are based on, says Lauren Colenso-Semple, CSCS, MS, PhD(c), who studies female exercise physiology and endocrinology. A menstrual cycle can be as short as 21 days or as long as 35 days, and ovulation can occur before or after day 14, she explains. In turn, your follicular phase might be anywhere from 10 to 22 days, or your luteal phase might be seven to 17 days, she says. If you don't know your ovulation day and you follow a standard program designed for a 28-day cycle, you might still be in your follicular phase when the plan is suggesting workouts for your luteal phase, Colenso-Semple says.

The hormonal fluctuations that cycle-synced workout programs are based upon are also relatively short-lived. "Estrogen is high for a few days, and the idea that the hormones would be so powerful they would influence your adaptations to training or your acute performance, that really isn't rooted in evidence at this time," Colenso-Semple says.

Essentially, the recommendations aren't as straightforward as what's being portrayed on social media, Olenick says. "There's maybe a small sliver or degree of truth or physiology that's happening, and then it's being extrapolated into poor exercise programming, or a hypothesis at best. At this time, the current body of the scientific literature does show some variations across the cycle, but this is probably more individual than it is prescriptive."

Resting during menstruation, taking it somewhat easy during the luteal phase, and setting PRs during the late follicular or ovulatory phase — as described online — isn't necessarily the best path forward for everyone who has a period, says Olenick. Hormonal contraceptives change naturally fluctuating levels of estrogen and progesterone, conditions like polycystic ovary syndrome can lead to irregular cycle lengths, and particularly active individuals may not experience the expected rise in progesterone during the mid-luteal phase or luteinizing hormone around mid-cycle, says Baranauskas. Due to these differences, workout programming should be fit to the individual, she notes.

There's also a real downside to the practice: Social media's cycle syncing advice encourages people to skip out on exercise or significantly reduce it for half of each month — for example, opting for high-intensity workouts only during the days around ovulation — which can make it difficult for them to reach their goals, says Colenso-Semple. "My concern with [cycle-synced workouts] is not only that it's not fully backed by the science, but it's really overcomplicating exercise training for women, and it's potentially hindering them from really making progress," she adds. This could cause people to lose motivation, she says, "especially if you're new to exercising."

If your goal is to make sure you're performing at your best, syncing your workouts to your menstrual cycle should typically be your last course of action, says Olenick. First, you should prioritize "low-hanging fruits" that are proven to make a difference in exercise performance and results, such as getting enough sleep each night; managing stress; eating enough calories, protein, and carbohydrates; hydrating well; and following a well-designed, consistent training program, she notes. If you're checking off all of those boxes, then it may be potentially beneficial to adjust your workouts based on how your body feels across the month, Olenick says.

Although there are caveats associated with cycle syncing, your menstrual cycle shouldn't be completely overlooked. Abdominal cramping, fatigue, and low-back pain before and during your period could all influence your performance in the gym and your motivation to exercise, says Colenso-Semple. "Being aware of that and adjusting that exercise session is completely understandable," she adds. "But we're talking about maybe one or two training sessions. That's very different from saying, 'For this whole half of the month, you should be doing something different.'"

If you want to take a more personalized approach to cycle-synced workouts, though, your best bet is to track your estrogen or progesterone levels with a fertility tracker or use a menstrual cycle tracking app to log specific symptoms, suggests Baranauskas. Before making any program changes, track your cycle for three to six months, as its length and symptoms can fluctuate depending on other factors in your life, such as your stress levels and nutrition habits, adds Olenick.

"Keeping track of how these symptoms influence the way you feel during specific types of workouts may help you more optimally schedule high-intensity workout sessions or competitions," says Baranauskas. "For example, if you note that you always feel low-back pain, joint pain, muscle cramps, and severe fatigue on day two of your menstrual cycle, this might not be the best day to schedule high-intensity workouts."

If you know your period falls at the end of the week, you might tackle your difficult workouts before it hits, do your "easier" workouts when you start menstruating, and add in another rest day, for example. "It's not a direct prescription, like: on a 28-day cycle, do this [workout] on days one through five, or only do this [workout] on days six through 15," says Olenick. "Do the same training that you normally do, but learn how to adjust and modify your intensity or your rest."

On the same token, don't let the research prevent you from following a training plan that works best for you. Although some early literature suggests you may be able to push your volume or frequency of resistance training during the follicular phase, that doesn't mean you can't aim for a new PR during the luteal phase, says Olenick. Unlike what social media users promote, "you don't need to be changing up the style or type of training that you're doing every single week," she adds.

Your menstrual cycle — and the uncomfortable symptoms that may be associated with it — could very well affect how you perform in the gym. And the cycle-synced workout programs touted on social media give people, particularly those who feel lost when it comes to exercise training, a straightforward plan that enables them to stay consistent with their physical activity.

The problem: These online cycle-synced plans are typically overgeneralized, and there's no set-in-stone, expert-approved prescription recommending menstruators skip or focus on certain types of training during particular times of the month.

In many cases, cycle syncing may simply lead you to pay closer attention to your body, which is nearly always beneficial and may be partly responsible for the practice's anecdotal positive effects. This is especially true for people who are used to restricting food and/or over-exercising, which can leave you feeling pretty crappy. When someone starts cycle syncing — a practice that reminds them it's OK to amp up or dial back the intensity of their training sessions if their body needs it — they may end up with a more appropriate volume of exercise, says Olenick. Or, at the very least, they might adopt a more compassionate approach to fitness. Really, this self-regulation is something a good coach should promote and a proper training program should take into account in the first place, she notes.

The bottom line: "Hormones are messy, so that makes the application [to fitness] messy," says Olenick. "And at the end of the day, right now, the best advice we have is to make it work for you."