Should You Sync Your Workouts to 
Your Cycle?

Let's talk periods. Ever since you got that "Your Period and You" leaflet in secondary school, you've known that it's a healthy part of life for every woman. And yet, we bet no teacher or doctor ever told you that menstruation—and the 28ish-day cycle it's part of—could potentially give you a performance edge.

Every female has oestrogen (which is mainly responsible for reproductive development) and progesterone (it preps your uterus for possible pregnancy). Their levels regularly fluctuate, which can affect the way you move, think and feel not just during your period but on every day of your cycle, says Georgie Bruinvels, PhD, a research scientist at the bio-analytics company Orreco. It's why one day you might feel like you have non-stop energy, and the next you're glued to your sofa and crying over an animal-rescue ad.

This flux can also affect how your body reacts to exercise, which can be a great thing. It means that, on any given day of the month, you can strategise when and how you train to get the results you want.

"Syncing to your cycle means adjusting your training and nutrition plan based on what's going on hormonally so you reap maximum physical, mental and emotional rewards", says Stacy Sims, PhD, a female-athlete physiologist and author of Roar, a physiology-based nutrition and training guide for active women. While the research on adjusting your training based on your cycle is constantly evolving, there may be benefits to putting it into practice.

If you go with your natural flow (read: no hormonal birth control, as most types affect hormonal shifts and thus require a different approach), this menstrual map from Sims will help you to navigate the distinct phases of your cycle. Just keep in mind that every body and every cycle is different, so results aren't guaranteed. But at the very least, trying a new routine could be a welcome change of pace—and you might uncover new intel about what makes your body feel good.

Let's get oriented: Day 1 is the first day of your period, the most nuanced stage of your cycle. Some women feel like total badasses—both oestrogen and progesterone are at their lowest during this time—while others are knocked sideways by symptoms, says Sims.

If you're feeling good, here's how to take advantage of this low-hormone state:

1. Go high intensity.
   Physiologically, you're in a good position to push yourself, so now's a good time to try some HIIT workouts and all-out sprints.
2. Get lifting.
   Pick up those heavy weights. Due to metabolic shifts, your muscles can recover from the stress faster.

Not you? If you're prone to period-related symptoms like cramps, brain fog and stomach issues, wait until they subside before attempting any of the above. (And eat anti-inflammatory foods rich in calcium and vitamins D and B such as bananas, plain yogurt and green leafy vegetables, says Sims.) Try some of these lighter activities instead:

1. Take a stroll.
   You might be tempted to curl up on the sofa (and you should definitely do that too!), but getting out can be good for the mind and body, says Sims. Go for a walk or a short run, perhaps to your favourite coffee shop. The movement will help release endorphins, your body's natural pain relief.
2. Think gentle movements.
   Increasing circulation can help relieve pain. One way to do that? Yoga. Opt for a slower, more gentle option, like yin or hatha. And take it further with simple motivational mantras to re-energise your mind and body.

However you're feeling, use this time to catch up on sleep—your body temperature is lower, which can deepen your natural sleep rhythms, says Sims. (Grab a hot-water bottle or heating pad if cramps are making it tough to pass out.)

Once menstruation is over and your hormones are still low, you're in a great position to push yourself. "You should feel more energised, clearer headed, better coordinated and ready to go hard in the gym", says Sims.

This physical and mental turnaround may be just what you need to take your training to the next level, all the way until your peak at ovulation. If so, try this:

1. Work on a new skill or activity.
   Whether it's pull-ups or Pilates, the surge in clarity and coordination could help you tackle an exercise you've never tried before. To set yourself up for success, choose something that's a progression of a movement you've already crushed. Love kettlebell swings? Try a KB snatch. Feeling solid in dolphin pose? Maybe kick into a headstand.
2. Go hard.
   Long story short, when your hormones are low, your body has an easier time accessing fuel for exercise, particularly the high-intensity type. On top of that, Sims explains, as your oestrogen starts to rise towards the end of this phase, so does your pain threshold. And on top of that, this hormone sweet spot primes beat-up muscles to repair faster and stronger. So sprint faster, WOD harder, chase that new record—your body can handle it.

When channelling your inner Mat Fraser, make sure you prioritise a regular sleep schedule and eat plenty of protein, healthy fats, complex carbs and colourful vegetables to optimise muscle repair, says Sims.

The third phase of your cycle starts right after ovulation (when an ovary releases a mature egg). The oestrogen levels dropping quickly at the beginning of this phase might leave you feeling flat, says Sims. No fun, though you can make the most of it if you:

1. Work on your endurance.
   Go for a hilly hike or a longer run, as steady-state cardio should feel more sustainable, says Sims. Lose the heavy weights and opt for lighter ones that you can lift for more reps, building your muscular endurance.
2. Learn to taper.
   As oestrogen plummets after you ovulate, it can tank your energy, says Sims. This is totally normal, especially if you're prone to PMS. Some movement might be more energising than none at all, says Sims. If you're feeling low-vibe, scale back your training as needed, either in intensity or duration, as going hard now might only deplete you further.

Or don't: Some people will feel fine throughout this phase, says Bruinvels. If that's you, feel free to think of it as a time to maintain your training rather than drastically advance or modify it, she says.

For most women, the week or so leading up to their next period is their least-favourite week. It's completely normal to feel anxious, irritable and blah at this point, thanks to high hormone levels, says Sims. You might even be completely fatigued, physically and mentally, or notice inflammation and bloating (hi, PMS). On top of that, peak progesterone levels typically activate your stress response, causing a higher resting heart rate and body temperature, which can make some movements feel harder than usual. Stay active, encourages Sims, as it can help you feel better all round. To strike the right balance:

1. Curb the intensity.
   If you aren't feeling up to your usual workout routine (fair), then don't do your usual workout routine. Drop the weight, shave some reps, extend your rest periods, slow your roll … just take things down a notch, says Sims. Or stick with low-intensity activities that help your body recover, such as yoga or Pilates. Bonus: These mind-body practices encourage you to focus on and control your breath, which can help regulate your heart rate and bring you into the present moment to help lower anxiety, she notes.
2. Treat yourself.
   Self-care was practically invented for this week. Enjoy a massage, bubble bath or anything that puts you at ease. Sims recommends spending time with friends and loved ones (even a call works if an in-person hang doesn't) to help boost levels of the feel-good hormone serotonin. Taking some downtime now should help you feel physically and mentally recharged for when your energy starts to pick back up in the early phase (your period and the days afterwards), allowing you to get back to training harder, explains Sims. It all comes full circle.

As you experiment with syncing your training to your cycle, remember: You have an opportunity to try different things every month as you learn about your hormonal patterns. But if you're not seeing or feeling much of a difference from all the trial and error, or you're stressing out over the process, it might not be for you. Ultimately, training in the way that works for your body and your temperament is what matters most. Period.

For more guidance, including workouts, check out the NikeSync programme in the Nike Training Club App or listen to the menstrual-cycle conversation between Lydia O'Donnell and Stacy Sims on the Nike Run Club App.