A woman points at a colour-coded grid dividing the menstrual cycle into four phases, each paired with its own list of exercises. "When you're bleeding, you want to be doing steady-pace jogging, Pilates, barre, walking, resting."
This is cycle-syncing — changing your workouts according to where you are in your cycle — and there are thousands of videos like it.
The scale of it
Google searches for the term have risen 740% since 2022. More than 55,000 TikTok videos now use the #cyclesyncing hashtag.
And the crucial line in the BBC's reporting: most of the advice is shared by fitness and wellness creators rather than medical or research experts.
What is actually known
It is worth separating two claims that get bundled together.
The first is that hormones fluctuate across the cycle and that many women notice real differences in energy, strength and recovery. That is not controversial. Anyone who has trained through a period knows the experience is not uniform across the month.
The second claim is the one being sold: that there is a correct prescription — this exercise in this phase — which will improve results. The evidence for that is thin. Studies in this area are typically small, use varied definitions of cycle phases, and produce inconsistent findings; there is no settled protocol that a trainer could apply with confidence. A colour-coded grid implies a precision the research does not support.
The practical position most sports scientists take is closer to: track how you feel, adjust accordingly, and do not force a hard session on a day your body is clearly refusing. That is cycle-syncing in its useful form, and it requires no chart.
What it means in Bangladesh
The content reaches here exactly as it reaches everywhere, because TikTok and Instagram do not respect borders — but it lands in a context where the base layer of information is missing.
Menstruation remains difficult to discuss openly in much of Bangladesh, school education on it is patchy, and a great many girls are told nothing useful before it starts. When the first detailed information a young woman receives about her own cycle arrives from a wellness influencer with a product, that is a problem of supply, not of her judgement.
Two things are worth holding on to. Exercise during a period is safe and often helps with cramps — the belief that girls should stop moving is far more damaging here than anything a cycle-syncing video promotes. And symptoms that stop you functioning are not something to optimise around: periods severe enough to keep a girl off school or work are a reason to see a doctor, because conditions like endometriosis, fibroids and PCOS are common, treatable, and routinely dismissed as normal pain.
The test for any advice of this kind is simple. Does it end with a supplement, a subscription or a programme? Then it is marketing that happens to contain some physiology. We set out the same reasoning about optimisation culture in sleepmaxxing.
