Your cycle
Cycle syncing your workouts: what's real, what's hype
The honest version: the physiology is real, the effect sizes are individual, and the scheduling logic is sound even where the science is still maturing. Estrogen's rise through your follicular phase (day ~1-14) supports strength gains, faster recovery, and higher training tolerance; the late luteal week brings higher core temperature, poorer sleep, and higher perceived effort for identical work. Training identically through both phases means fighting your body for two weeks per month.
What cycle syncing is not: a reason to skip training for half the month, or a rigid prescription where you can only lift on day 9. It's periodization using a calendar your body already runs — put your intensity PRs and hardest sessions in the follicular window, shift late-luteal week toward volume maintenance, technique, walks and recovery work, and keep showing up daily throughout. Same monthly workload, placed where it lands best.
The two halves, physiologically
Follicular (period start to ovulation): estrogen climbs, and with it neuromuscular efficiency, pain tolerance, and glycogen use. Many women hit strength peaks around ovulation. This is the window for progressive overload, intervals, and the sessions that scare you a little.
Luteal (ovulation to next period): progesterone dominates, raising core temperature ~0.3-0.5°C, nudging heart rate up, and fragmenting sleep for many. The final week adds PMS for a majority. Identical workouts feel harder because they physiologically are — RPE research bears this out even where performance metrics stay flat.
What the research actually says
Meta-analyses land on 'plausible, individual, under-studied': some trials show meaningfully better strength adaptations from follicular-loaded training, others show little difference, and nearly all note huge person-to-person variance. Hormonal contraception changes the picture again by flattening the cycle.
The practical conclusion isn't 'ignore it until science settles' — it's 'track your own data'. Your energy, sleep, and session quality logged against your cycle for two months tells you more about your body than any group-average study ever will.
A 75-day challenge meets a 28-day cycle
Seventy-five days spans roughly two and a half cycles — which means two and a half late-luteal weeks where a rigid daily-workout rule collides with your hardest week. This is where challenges without cycle awareness quietly break women who were doing everything right.
The fix isn't exemption; it's substitution. Your daily movement requirement stands, but late-luteal days steer toward the active-recovery end of your plan — the long walk, the mobility session, the easy swim — and your PR attempts wait for the follicular week when they'll actually land.
Automate the calendar math
Nobody wants to cross-reference a cycle app against a challenge tracker against a training plan every morning. 75 Her folds them into one: you tell it where you are in your month — nothing is read or predicted — and today's promises arrive already tuned. Push where your body can push, gentle where it can't, day count intact throughout.
Your cycle stops being the thing that breaks week six and becomes the scheduling engine that gets you to day 75. That's the entire idea.
The challenge, held properly
75 Her
Five versions from 75 Soft to 75 Hard, daily promises that flex with your cycle, a private proof-photo ritual, and the Day 1 vs Day 75 reveal at the end. Coming to iOS.