Sela Breen has seen the trend.
It’s everywhere on social media.
Influencers swear that your estrogen levels dictate how you sweat.
The pitch is seductive.
Train gently when bleeding.
Go absolutely berserk during ovulation.
It’s called cycle syncing.
It sounds logical, doesn’t it?
Hormones change, so should your workout.
Except a new study says… not really.
The Test
Researchers gathered ten healthy women.
Average age? 23.
They all have regular cycles.
Here was the deal:
Each woman performed a Wingate anaerobic test.
This isn’t a leisurely jog.
It’s thirty seconds of max-effort cycling until your lungs burn and legs turn to jelly.
They did it three times.
- Early follicular phase (period week).
- Late follicular phase (pre-ovulation).
- Mid-luteal phase (post-ovulation).
No guesses involved.
They verified the phases with ovulation strips.
Self-reporting counted.
But the bike measured the truth.
They tracked peak power.
Average power.
How fast they got tired.
And how much they thought it hurt.
The Result
Here is the punchline.
Nothing changed.
Statistically speaking?
The data looked identical across all three phases.
Peak power. Same.
Fatigue. Same.
Perceived effort. Same.
Your body did not care which week of the cycle it was.
You hit the pedals hard in February just as you would in May.
This fits with other research too.
A 2025 review concluded anaerobic power doesn’t shift with hormones.
There is a gap though.
Between how women feel and what the sensors record.
Athletes report feeling worse during their period or late luteal phase.
But the numbers?
They lie… or rather, they don’t lie about the output.
The feeling is real.
The performance drop?
Mostly imaginary.
Stop Modifying. Start Moving.
If you sprint intervals.
If you lift heavy iron.
Drop the cycle syncing for anaerobic work.
It’s unnecessary complexity.
Coaches can breathe easier too.
They don’t need a calendar to schedule your sets.
Admittedly…
This was a small group.
Only ten women.
All recreationally active.
It wasn’t testing endurance marathons.
Or years of strength adaptation.
Or women with irregular cycles.
So take it with a grain of salt?
Maybe.
But the trend points one way.
How To Train Anyway
You don’t have to guess.
You have data now.
Ignore the phase.
Train consistently.
Don’t build “deload” weeks into your schedule unless your body is breaking.
Just keep showing up.
Watch symptoms.
Feel sluggish?
Rest if you must.
But don’t rest because a blog post says Day 3 means low energy.
Trust the gut, not the graph.
Cycle syncing sells wellness products.
Consistency sells results.
The science is thin on modifying high-intensity work for hormonal peaks.
Your body is an organism, not a clock.
Listening to yourself still matters.
Cramps hurt.
Sleep disruption stings.
These are valid reasons to scale back.
But fear of missing an ovulation window?
Leave it at home.
You might feel different.
The data suggests you won’t perform different.
Which one will you believe?
