Proponents of cycle syncing believe the hormonal peaks and valleys can help to determine when to go for a personal record and when to pull back.iStockPhoto / Getty Images
When it comes to athletic performance, everyone wants to get an edge. That might mean taking supplements or test-driving a new sneaker that promises to make you lighter on your feet. But what if instead of seeking outside assistance, you could hack your body’s internal system to optimize your health and fitness?
When 26-year-old weightlifter Monica Knowlton tried syncing her workout intensity to her menstrual cycle two years ago, she noticed improvements in both her physical performance and mental strength. She scheduled her highest intensity days to correspond with her follicular phase when she feels her strongest and matched her de-load week (a drop in volume and intensity at the end of one training program and before the start of the next) with the days when she tends to experience premenstrual symptoms.
“This makes me feel better mentally, knowing when to push the gas and when to pump the brakes,” she says.
Still, Knowlton is careful not to give full credit for this shift to her hormone levels. “Performance-wise, although I was improving, it is impossible to say if it was because of the cycle syncing,” she said.
Cycle syncing is the practice of adjusting your workout intensity, diet and recovery based on phases of your menstrual cycle. Proponents believe the hormonal peaks and valleys can help to determine when to go for a personal record and when to pull back. So, how does it work?
The basics of cycle syncing
Most people who experience a naturally occurring menstrual cycle go through four phases: menstruation, follicular, ovulation and luteal. With each phase, hormone levels rise and fall which for some can lead to bouts of tiredness, changes in mood, bloating, headaches and cramps.
To adjust your workout accordingly, that might look like low-intensity activities such as walking or yoga during menstruation when energy levels might be lower; cardio-based and high-intensity workouts like running and heavy lifting as energy levels increase in the follicular and ovulation phases; and strength training or medium-intensity exercise during the luteal phase leading into menstruation.
Why is it so popular?
“A lot of women sincerely feel like fitness and science and health has left them out for a long period of time,” says exercise scientist Alyssa Olenick, PhD.
Between 2014 and 2020, only 6 per cent of studies in sports and science journals focused exclusively on women, writes Christine Yu, author of Up to Speed: The Groundbreaking Science of Women Athletes. So, it makes sense that a practice based solely around sports and the female reproductive system would feel compelling.
While you can now hire a coach or buy a program to help you schedule workouts around your cycle, there still isn’t a lot of research to back up the notion of basing your training on typical – but by no means universal – cycle lengths and symptoms.
But does it work? Yes and no.
The average cycle is 28 days but can range anywhere from 21-35 days for someone not on a contraceptive, with the number of days spent in each phase differing from person to person. Similarly, symptoms such as exhaustion and cramping are typical but not a given, which means not everyone will see the same benefits from taking a week of rest, just as not everyone will hit a personal record simply because they’re in a specific phase of their cycle.
For those on a contraceptive, the structured form of cycle syncing may also be a poor fit, as they don’t experience those typical hormone fluctuations. That can make a one-size-fits-all program challenging to adhere to.
Lauren Colenso-Semple, PhD, and fellow researchers at McMaster University evaluated a series of meta-analyses and systematic reviews on the influence of the menstrual cycle on sport performance and strength performance. They concluded that “in the absence of high-quality evidence to support designing resistance training programs based on menstrual cycle phase, coaches and athletes should tailor an exercise plan to the individual.”
Other reports on cycle syncing, including a 2020 meta-analysis of 78 studies based on endurance- and strength-based outcomes, have come to similar conclusions.
When it comes to adjusting a training session because you have menstrual symptoms, Colenso-Semple says, it can be impactful to listen to your body. “But that’s really different from saying ‘For these two weeks you should be doing yoga and for these two weeks you should be doing strength training,’” she says. “Because those sorts of recommendations are really antithetical to everything we know about sound exercise programming.”
The advice to force yourself to rest can also feel a bit archaic as a pre-set program may or may not coincide with the sensations in your own body.
“When we start getting into the advice of ‘Don’t do any intensity, you just need to sit and abstain from anything intense or heavy for somewhere between seven to 14 days a month,’ It starts becoming belittling and kind of increasing this narrative around fragility in females which I think we’ve worked really hard to move past,” Olenick says.
How you can decide for yourself
Sonya Romanowski, a 33-year-old strongwoman athlete, doesn’t experience impactful enough hormone fluctuations throughout her cycle to shift her entire training regimen, but like Knowlton, she tries to plan her de-load for the start of menstruation.
“I ease off higher percentage training and don’t attempt any personal records during that time,” she says.
If you’re curious about what it might feel like to take your cycle into consideration when planning your workouts, Olenick recommends following the lead of your own body.
“I encourage people to track their cycle for three to six months to figure out their true pattern and recognize where sometimes things shift or change,” Olenick says. She suggests assessing your rate of perceived exertion – how hard you think you’re pushing yourself during exercise – on a scale of one-to-10 and using that to adjust training intensity. Exercisers should keep in mind that things like nutrition, hydration, stress and life fatigue – not just your hormone levels – all have an impact on your training.
“Adjusting your training based on your own individual response and needs isn’t cycle syncing,” Olenick adds. “It’s just good training.”
Alyssa Ages is a journalist and the author of Secrets of Giants: A Journey to Uncover the True Meaning of Strength. She is also a strongman competitor and endurance athlete, as well as a former personal trainer and group fitness instructor.