It’s time to separate science from social media in the world of menstrual cycle training and syncing.

You have probably seen the advice: match your workouts to your menstrual cycle and you will train smarter and stop fighting your own body. It usually arrives with a tidy chart telling you to lift heavy on some days and go easy on others.

I went looking for the research behind it, because if it worked I wanted to teach it. It does not hold up. And if you are in perimenopause, it falls apart faster, for a reason most of these charts never mention.

Cycle Syncing and What the Research Actually Shows

If you are in perimenopause, the calendar has already stopped working

Cycle syncing depends on knowing where you are in your cycle. In perimenopause, that is exactly the thing that becomes unreliable. Cycles run shorter or longer from one month to the next, periods skip, and some months you do not ovulate at all. A plan that says “day 8 is a strength day, day 22 is a rest day” assumes a steady 28-day rhythm you may no longer have.

So we do not even need the studies here. You cannot sync to a cycle you cannot predict. For most women in the transition, that alone is the answer.

The advice is built on weak studies

Set perimenopause aside for a moment and look at younger women with regular cycles, where cycle syncing is supposed to apply. Even there, the evidence is thin.

The catch is in how the studies worked out which phase a woman was in. Most of them counted days on a calendar instead of confirming the phase with a blood test or an ovulation test. Counting days assumes ovulation happened, and happened on schedule, which often is not the case. When researchers looked only at the studies that verified the phase properly, the supposed differences between cycle phases mostly disappeared.

A 2020 review led by McNulty laid this out. Before accounting for how carefully each study confirmed the phase, most looked like reasonable-quality work. Once that was factored in, only a small fraction held up. A broader 2023 review by Colenso-Semple reached the same place: there is no meaningful effect of cycle phase on strength, or on the muscle you build from training.

Small biological changes across the cycle are real. They are just too small, and too all over the place from one woman to the next, to build a training plan on.

What Actually Changes Your Results

Here is where the research actually gets solid, and it is far more useful than any phase chart.

Strength training protects your bones, and the benefit shows up when the training is properly hard, not light and easy. In a recent analysis, the gains at the hip came through when women trained at roughly seventy percent or more of the heaviest weight they could lift once. Adding impact work, the kind where your feet leave the ground like jumping or hopping, builds on that bone benefit, and it holds for women both during and after the menopause transition.

For body composition, resistance training is what builds and keeps muscle, while cardio does more of the work for fat loss, so most women want some of each. Higher-intensity intervals help with body composition too, without a clear edge over steadier moderate cardio, so you can use whichever you will actually keep doing.

None of this depends on the day of your cycle. It depends on training regularly and hard enough, eating enough protein, sleeping, and leaving yourself room to recover.

What To Do Instead of Cycle Syncing

Pay attention to how you feel on the day. Some women do notice patterns across the month in their energy or their motivation, and that is worth using. You are reading your own body as it is, right now, instead of trusting a rule someone drew up for an average cycle that may look nothing like yours.

A workable approach: train strength two or three times a week and add weight over time, put in cardio in a form you enjoy, and protect your sleep and protein. On a day you feel strong, push. On a day you feel flat, do a lighter version and keep the habit going.

Originally Published by Catharine Adams
This article was first published on Evidence-Based Perimenopause and is shared here with permission.

References

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