But when you think about it, the idea makes so much sense that its shocking its not commonplace. The way you move and breathe, how your heart beats, and your bodys reaction to exercise varies throughout your menstrual cycle, says Georgie Bruinvels, PhD, co-creator of FitrWoman , the app the USWNT used.

Any woman can maximize her workouts by learning to go with her flow.

Turns out, tailoring your routine to your cycle, a technique known as phase-based training, empowers you to take advantage of your physiology to look and feel your best and to perform at your fullest potential, according to Womens Health advisory board member Stacy T. Sims, PhD , whos been researching female athletes for 20 years.

And its not just for fitness pros either. Any woman can maximize her workouts by learning to go with her flow. No matter your goals, the right training during specific times of the month will optimize outcomes, says Sims.

The first step? Get to knowlike, really knowyour cycle. A period-tracking app (there are many; you'll see) can help you understand each part of itand how it impacts the body.

From there, use this guide to tweak your get-sweaty routine. Youll be amazed by how good you feel once things are truly, totally simpatico.

Menstruation: Days 15

Right about now (the start of your period), low levels of estrogen and progesterone (plus extra inflammation) may have you feeling pretty unmotivated to get moving, says Bruinvels (womp womp). But its actually prime time to build strength and muscle , thanks to relatively high testosterone, Sims notes.

Do whatever workouts feel good.

If youre craving easy, restorative movement, focus on low-intensity workouts like yoga , Pilates, and stretching during your period, says Bruinvels.

Butif you feel energized, hit the weights and lift heavy, says Sims. In fact, go for loads you can manage for only six reps, tops. (Try five sets of five reps at 80 percent of your one-rep maxi.e., the most weight you can lift for one rep.)

Follicular Phase: Days 614

Between the end of your period and about three days before ovulation, estrogen levels spike, which means youll have more energy to work out and recover faster. Woo! Estrogen is associated with feeling happy, engaged, and strong, says Bruinvels.

Now's the time to up your training intensity.

If you feel next-level amazing, make the most of it by continuing to lean in to strength training, plus sprints and intense workouts. Nows the time to bust out that jump rope or join a boot camp class and really push!

Ovulation: Days 1523

Things get a little wonky in this part of your cycle. Around ovulation, estrogen briefly drops while progesterone increases. FYI: Higher levels of progesterone can contribute to muscle breakdown, making proper recovery even more important than usual, says Bruinvels.

Stick to steady state cardio and strength training.

Help your body bounce back by switching to moderate-intensity exercise, Sims says. Swap sprints for easy runs and stick to weights you can lift for eight to 10 reps. If you feel super sore, give yourself an extra day between workouts, Bruinvels adds.

Luteal Phase: Days 2428

At this point, both estrogen and progesterone levels fall. As a result, PMS symptomslike irritability and anxietystart to creep up, while fluctuating blood-sugar levels and inflammation sap precious motivation.

Start winding down your fitness routine.

Since your body isnt in peak performance condition right now (and you probs dont have World Cup glory on the line to fire you up), use exercise to reduce stress. Opt for Pilates , yoga, or slow runs.

When strength training, focus on form. Nailing it now will prepare you to load more weight when a new cycle starts, says Sims.

The Best Cycle-Tracking Apps

To create the best routine for your body, you gotta become BFFs with your cycle. These apps can help you log (and decode!) each phase.

This article appears in the July/August 2020 issue of Womens Health. Subscribe now .