Try it: cycle syncing

Throughout the menstrual cycle you might experience cramps, cravings, as well as energy surges and droughts, all of which can feel like short-term roadblocks to a healthy lifestyle. But that's only true if your habits stay static throughout those 28 days.

Hormonal fluctuations directly affect energy levels, muscle and joint function, and even your skin health, says Jiji Pollock, an exercise physiologist and health and human performance coach at the Institute of Motion in Walnut Creek, California. By adjusting your routine accordingly, you can actually take advantage of these ebbs and flows for clearer skin, stronger workouts, and better nutrition.

That’s why experts created the comprehensive four-week plan below, which takes these hormonal changes into account for a more optimized routine for women.

Some exceptions: This plan doesn’t apply to you if you don’t ovulate, if your body doesn’t follow a four-week cycle as is the case in women with PCOS, or if you take hormonal birth control (see box above). "But for women who are generally in the 28-day cycle, this is a good plan to follow," Pollock says.

Menstrual phase: days 1 to 7

The start of your cycle is marked by the first day of your period. Along with bleeding, cramps, and changes in mood (whether positive or negative), you’ll likely experience a drop in energy, Pollock explains.

The reason for this is twofold. First, your body produces less testosterone during menstruation, she says. The hormone stimulates the production of red blood cells, which carry oxygen to your tissues. So it follows that when your levels are low, less energy gets delivered to your muscles. That, coupled with period-induced blood loss, can contribute to overall feelings of sluggishness.

Because of all this, you want to schedule lower-intensity workouts that activate the parasympathetic nervous system so you can feel restored, says John Sinclair, an Alberta, Canada-based programming officer and performance coach for the Institute of Motion. He recommends yoga, Pilates, and lower-load resistance training.  

You don’t have to scrap your regular workouts altogether as long as you squeeze in some extra rest. If on one day you log a moderate-intensity run, use the next for recovery. “The goal is to allow for regeneration,” Pollock says.

You’re also more prone to injury during week one thanks to an increase in the hormone relaxin, which loosens the ligaments in the joints, she adds. “That might sound great for flexibility, but it actually means that your joints don’t stay intact during times of stress.”

Your knee joint, for example, will be less secure than normal, so if you put too much pressure on it while squatting or doing plyometrics, your risk of injury goes up. Because of this, she suggests avoiding high-impact exercises like box jumps and heavy lifts.

Follicular and ovulation phases: days 8 to 21

At this point you’ll start feeling more energized, since testosterone picks up again and more blood and oxygen gets delivered to your muscles. “It’s when you can really ramp up the intensity, lifting heavier, going faster, and moving with more degrees of freedom,” Sinclair says.

Throughout the follicular phase (week two) and into ovulation (week three), estrogen and follicle stimulating hormone (responsible for triggering ovulation) levels rise, strengthening the integrity of your joints. Better yet, testosterone peaks in week three, making it the ideal time to put high energy levels to use.

Sinclair suggests taking advantage of these factors in weeks two and three by doing more HIIT and HISS workouts like Tabata and AMRAP as well as plyometrics. When lifting, do so at approximately 75 to 90 percent of your one-rep max. You can do up to three high-intensity workouts per week, Pollock says, with moderate or recovery days in between.

Luteal phase: days 22 to 28

Testosterone’s spike in week three is followed by a fall in week four, and your energy levels will follow.

Training during week four should focus more on SISS workouts like moderate-intensity running, swimming, or cycling. Resistance training should be done at 50 to 65 percent of your one-rep maximum.

If you do opt for intense exercise, you may find you need more rest. To prep for your period, your body produces more progesterone. Research shows too much of the hormone can block signals being sent from the brain to the muscles to synthesize collagen.

“When that happens, you recover more slowly,” Pollock says. Pamper yourself a little more than usual with rest, a massage, foam rolling, and steam sessions.

And be sure to prioritize your sleep hygiene: A new study found that women woke up three extra times and for 15 additional minutes each night at the end of the luteal phase compared to the beginning of the follicular phase. Eat within a 12-hour window and perfect your nighttime routine to get more rest so you can give 100 percent in and out of the gym.