What is fitness cycling?

It's not you, it's your hormones.

Fitness is a funny beast. Weeks of sustained progression and seemingly minuscule gains can feel as though they've been erased overnight, and it is more than just falling out of the habit. Stepping back into the gym after a few days off carries a very specific dread, the kind you might remember from heading back to school after the summer holidays, convinced you'd forgotten everything from the term before and should probably just quit while you're ahead. You had not forgotten. You did not quit.

Then you hear the other side of the argument, that rest is good. Athletes have de-load weeks written into their programming as standard. Armed with that fact and given the right mood, you can justify almost any break from training under the banner of muscle memory.

Rest is good, burnout is not

To offer some clarity: rest is good, burnout is bad, and over-training is a direct route to the latter.

As women, you are particularly vulnerable to over-training. Fitness programmes have historically been designed for men, and they fail utterly to account for the hormonal shifts that happen throughout the month. You don't talk about it much, but you've all lived it, nailing a personal best on a Tuesday and barely surviving the warm up two weeks later.

You haven't lost fitness, you've lost the plot the industry sold you

You have not lost fitness. You have not lost willpower. You are living in a body that runs on a monthly cycle, and for years the fitness industry has trained you to ignore that fact entirely. You're told to show up, push hard and treat every day as though your hormones hold steady. They do not. They rise and fall in a fairly predictable rhythm each month, and once you understand that rhythm, training stops feeling like a fight against your own biology and starts feeling like a partnership with it.

This isn't about doing less. It's about doing the right thing at the right time, which, if you measure progress in PBs and Hyrox splits, is the more ambitious approach, not the softer one. Elite athletes and their coaches have been quietly cycle syncing for years. It is only now filtering down to the rest of us, partly because the research finally exists and partly because women are asking why nobody mentioned this sooner.

Your cycle has four phases, each with its own hormonal weather

The menstrual cycle moves through four broad phases, and each one comes with its own internal climate. Understanding what's happening explains a great deal about why some weeks feel unstoppable and others feel like wading through wet sand.

Menstruation opens the cycle, with both oestrogen and progesterone sitting low. Energy tends to dip here, and training can feel harder than it should. This is not the week to chase a one rep max. Gentle movement, walking, mobility work and lighter cardio tend to feel better while keeping momentum ticking over. Some women train completely normally through this phase too, and that's fine. The point is to listen rather than override.

The follicular phase runs from the end of your period through to ovulation, and this is where oestrogen begins climbing. Many women feel sharper, stronger and more motivated here, with better pain tolerance and quicker recovery between sessions. This is the phase to schedule your hardest strength work, your intervals and anything that demands real grit, because your body is genuinely better equipped to handle it. A new programme, a heavy lifting block or a Hyrox race all belong in this window.

Ovulation sits at the midpoint, when oestrogen peaks alongside a surge in testosterone. This is often when you feel your most powerful in the gym, and it is no coincidence that some of your best lifts land here. Joint laxity also increases slightly around ovulation thanks to relaxin, so a proper warm up matters more than ever, particularly before heavy compound lifts or sprint work.

The luteal phase is the longest stretch, as progesterone rises and oestrogen fluctuates before both drop away towards the end. The early luteal phase can still feel strong, but as it progresses, especially in the week before your period, energy tends to dip, body temperature rises and recovery takes longer. Steady state cardio, moderate strength work and a more forgiving approach to the numbers on the bar tend to serve you better than chasing PBs here. Cravings often climb too, which is simply your body asking for more fuel, not a lapse in discipline.

Tracking beats guessing

The practical upshot is refreshingly simple. Track your cycle, even loosely, using an app or a note on your phone, and start paying attention to patterns rather than dates alone. Notice when you feel strong and when you feel flat, then plan your training around it. Save the heaviest lifting and the fastest intervals for the follicular phase and ovulation, and let the luteal phase and your period carry the steady, sustainable work that builds a base without draining you further. This isn't about skipping sessions during the harder weeks. It's about adjusting intensity rather than abandoning consistency altogether.

Every cycle is different, and every woman's experience of her own is different too. Some train through every phase without noticing a shift, others feel it acutely, and hormonal contraception changes the picture again by flattening some of these natural fluctuations. The goal was never a rigid rulebook. It's building enough awareness of your own patterns to make informed choices about when to push and when to ease off.

Working with your body is the harder, smarter option

Fitness culture has rewarded relentless consistency above all else for years, as though strength only counts when it's achieved by brute force regardless of how you feel. Working with your cycle is, if anything, a more sophisticated form of discipline. It takes more self awareness to scale back in your luteal phase than to simply push through, and more planning to front load your hardest sessions into the follicular phase than to train on autopilot. What you get back is better performance, fewer injuries, less burnout and a far healthier relationship with your own body.

Training with your cycle rather than against it isn't a trend. It's just training with better information, and you'll likely wonder why nobody handed you this manual years ago.