Illustration by Emma Günther
The truth about cycle syncing and exercise
What the latest research says about coordinating exercise with your menstrual cycle.
Please note that if you are using hormonal birth control, you may experience different hormonal changes than the ones described in this article.
Top things to know:
Regular exercise and strength training can reduce premenstrual symptoms such as pain, breast sensitivity, and anxiety.
While there is some evidence that hormonal fluctuations during your menstrual cycle can influence exercise and training, cycles vary from person to person and cycle to cycle.
Paying attention to your body and tracking your energy levels is the best way to figure out an individualized approach to exercise, which clinicians and researchers recommend.
Cycle syncing is the practice of coordinating your daily activities, like exercise, nutrition, sleep, and work, with the hormonal fluctuations of your menstrual cycle. Doing so is said to have a myriad of benefits like easing menstrual symptoms, boosting energy, mood and fertility, and balancing one's hormones. When it comes to exercise, cycle syncers are commonly advised to limit exercise when hormone levels fall before and during one's period. They are also encouraged to do high-intensity exercises when estrogen levels are high. Anecdotal evidence suggests that doing so allows you to take advantage of high energy levels (1).
And while there is evidence that hormonal fluctuations during your menstrual cycle can positively influence exercise and training, it’s hard to pinpoint your exact hormone levels each day. Plus, cycles are rarely consistent, vary from person to person, and can be affected by environmental circumstances like stress and your lifestyle (2), so it is misleading to claim that everyone with a cycle should do strength training on, say, day 14 of their cycle, or during, say, the luteal phase.
Cycle syncing can also be unrealistic for the average person. Many of us find it difficult enough to fit in basic exercise during the week, much less organize exercising around the specific phases of our menstrual cycles. Since regular exercise and strength training are scientifically proven to improve overall health outcomes and reduce premenstrual symptoms such as pain, breast sensitivity, and anxiety (3), cycle syncing could even be counterproductive if it leads to less exercise.
More research is needed to better understand how exercise and the menstrual cycle are related. But, for now, women and people with cycles are underrepresented in sport and exercise studies. The majority of this research (as well as most research in general) focuses on male participants (4). Where there is research with female participants, the menstrual cycle is not frequently taken into consideration (5), and even when it is, the quality of these studies tends to be low with small sample sizes, methods that are difficult to compare, and conflicting results (6).
This means that we unfortunately still don’t know much about how hormonal changes might impact sports performance and therefore, how to best adapt exercise routines to address these changes. Read on for answers to the most commonly asked questions about cycle syncing and the latest research on cycles and fitness.
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The basics of cycle health
The menstrual cycle might be considered the fifth vital sign since it can indicate a lot about the state of your body. Your cycle affects sleep, mood, energy, bone health, metabolism, and heart health, among other things. And it can be an indicator of how well your body is functioning. (7). Your cycle can likewise be affected by external factors like diet, sleep, other medical conditions, and physical activity (8).
A refresher on the basics of the menstrual cycle: There are two main phases of the menstrual cycle, separated by ovulation (when an egg is released from one of the ovaries): the follicular phase and the luteal phase. The follicular phase is the first part of the cycle, from the first period day until ovulation, lasting approximately two weeks in a typical menstrual cycle (although this may be longer or shorter and varies between people). The luteal phase is the second part of the cycle and is the time between ovulation and your first period day, lasting approximately two weeks in a typical menstrual cycle. Progesterone and estrogen, which are produced primarily by the ovaries, are the two main hormones that regulate your cycle and can also impact many other processes in your body (7) and can affect exercise.
Frequently asked questions about cycle syncing and fitness
Is there an optimal time to do high-intensity workouts during my cycle?
Possibly, when estrogen levels are elevated. But without daily testing, we are currently unable to identify when those peaks would be or to what extent they would be helpful.
Higher estrogen levels are associated with increased muscle building, increased energy storage, and lower risk of injury (6,9). So it's possible that you have more energy and that workouts feel easier when your estrogen levels are elevated during your cycle. In a typical cycle, estrogen normally peaks twice, initially in the days before ovulation and then during the mid-luteal phase (10).
While it’s tempting to try to schedule your high-intensity workouts during these estrogen peaks, it can be difficult to do so. Cycles are just too variable month-to-month and too dependent on each individual and their environment to optimize in this particular way. Plus, the hormonal effect is likely very subtle, with most people being unable to detect a change in energy or performance at all (6).
Tracking your cycle with Clue, on the other hand, may help you understand when your energy levels are high, which can, in turn, help you prepare for when you might want to take on new or more challenging workouts (and possibly take advantage of estrogen peaks).
Should I limit myself to low-intensity exercise before & during my period?
Not necessarily! When estrogen and progesterone levels fall in the days before your period, many people experience a decrease in energy along with an increase in premenstrual symptoms such as fluid retention, mood changes, and pain, which can play an important role in how you feel when exercising (11,12). While these symptoms may hinder some people from doing exercise, others might find exercise beneficial for helping to relieve these symptoms (3). If you're not feeling up to your normal cardio or HIIT class, a more gentle form of exercise like yoga or a walk may be a more suitable choice for you during this time. However, not everyone experiences cycle-related symptoms, and there's no reason to modify your exercise routines unless you do.
Some evidence suggests that exercise performance may be reduced at the start of the period, compared to other phases of the menstrual cycle (6). You may notice you have less energy and find your workout more difficult than you usually would. However, fluctuations in exercise performance across the cycle are likely minimal for most people, and many may not notice a difference at all (6).
Rest is an important part of any fitness routine or training program. If you feel tired while exercising, it may be helpful to incorporate longer recovery times, try lighter exercises, or even take a rest day, regardless of where you are in your cycle.
On days when you have low energy, a low-impact workout, yoga flow, or Pilates class can help you get moving without an all-out intensity.
Track your cycle with Clue, to determine what’s best for you.
Is there an optimal time to do strength training during my cycle?
Maybe, but the studies are limited and more research is needed.
Regular strength training each week is an important part of improving and maintaining health (13). Some early studies indicate that high-intensity strength training sessions during the late follicular phase when estrogen levels rise and peak, can lead to higher muscle mass gains when compared with strength training done during the late-luteal phase (14,15).
Training during the late follicular phase may also have additional benefits: elevated estrogen levels may also provide some protection against exercise-induced muscle damage and lead to less muscle inflammation post-workout (9). Another study found incorporating strength training into one’s routine during the late-follicular and mid-luteal phase (two times of the cycle characterized by increased estrogen) could lead some people to find it easier to lift heavier loads and need less recovery time (16). And, estrogen may increase pain tolerance (17), so lifting heavier weights may feel more manageable during these times.
You may also feel less sore during the mid-luteal phase. Increased levels of progesterone and estrogen may lead to a lower chance of delayed onset muscle soreness (DOMS or the feeling of muscular discomfort 24–48 hours after intense exercise) and strength loss (16). DOMS and strength loss may be more likely to happen during menstruation (16).
Still, cycles tend to be variable and everyone's cycle is individual. While these studies offer a great framework to consider when you might challenge yourself to lift more or less, it's more important to modify your workout based on how you're feeling every day.
An individualized approach is best
Your body is not a clock and your cycle is influenced by many things in your life, including your hormones. Even if you have predictable periods, you may still experience some changes from cycle to cycle, including when you ovulate and what symptoms you experience (18). That's why getting to know your body and tracking what works for you is often the best approach to exercise.
Getting 30 minutes of aerobic activity five days a week is proven to maintain your overall health, improve your brain health, and reduce your risk of developing chronic diseases (13).
To learn more about your unique cycle and gain insights into how your cycle affects your fitness routine, track your experiences in Clue.
