Knowledge
Articles on women's health, including topics that rarely get talked about. We describe what is known and cite a source for every statement.
Myth check: cycle, training, women's health
31 common claims about cycles, training and women's health, each with a verdict and a source.
What we've changed – and why
8 changes to the app, each with before, now, reasons and sources.
Body & health
Iron, periods and exercise: test first, then supplement
Can iron deficiency make your period stop? What the NHS lists as causes, why it's usually the other way round, which blood value counts and why not to take iron on suspicion.
Endometriosis: why diagnosis takes so long
About one in ten women has endometriosis, and diagnosis often takes years. How to recognise it and what the new 2025 guideline changes.
Pelvic floor: incontinence is common – and very treatable
A few drops when jumping or lifting: hardly anyone talks about it, including many athletes. How common it is and which training is proven to help.
Pain during sex: common, but not normal
Many stay silent about it, out of embarrassment or because they've been told that's just how it is. Common causes, from after childbirth to endometriosis, and what a physiotherapy trial shows.
Heart attacks in women: the signs are not “atypical”
Women with a heart attack reach hospital later than men. Which signs women have more often and when to call the emergency number straight away.
Iron deficiency without anaemia: when the blood count is normal
Low ferritin but a normal blood count? What it means, why it's so common in women and what the studies say about treatment.
Cycle & period
The luteal phase: the two weeks before your period
What is the luteal phase? The time from ovulation to your period, usually 12 to 14 days. Typical symptoms, how discharge and temperature change and what counts as too short.
Cravings across the cycle: before your period, around ovulation, during
Cravings and binges before your period: how much more women eat then, how long it lasts, what PMS and sleep have to do with it and what helps. With sources.
Gained weight before your period? It's usually water
Do you gain weight before your period? Studies that measure it find half a kilo at most on average, and it's water. When it peaks and which day is worth weighing on.
How long is a normal cycle – and when is ovulation?
28 days and ovulation on day 14 – true for very few. What counts as a normal cycle length, why ovulation varies and how to estimate it sensibly.
Heavy periods: how much is too much?
Changing every two hours, clots, longer than seven days: how to tell if your period is too heavy, what can be behind it and why iron matters.
PMDD: when it's more than PMS
For a small group, mood before the period tips so far that daily life suffers. What PMDD is, how it is diagnosed and what the evidence says about treatment.
Life stages
Menopause: all articles at a glance →
Perimenopause: the years hardly anyone talks about
Menopause doesn't arrive overnight at 50. Which signs are often overlooked, how long symptoms last and why contraception is still relevant.
After your last period: menopause and postmenopause
When it counts as menopause, what carries on afterwards and which bleeding always needs checking. With sources from the WHO and the NHS.
Hormone therapy for menopause: what counts as established today
Who usually benefits more than they risk, how large the breast cancer risk is and why patches work differently from tablets.
Hot flushes without hormones: what's backed by evidence and what isn't
Behavioural therapy, hypnosis, medication: what the Menopause Society recommends. And why exercise, soy and herbal products aren't on the list for hot flushes.
Vaginal dryness after menopause: common, rarely discussed
Dryness, burning, pain during sex, more frequent cystitis: why this often persists after menopause and what studies show helps.
Early menopause: when periods stop before 40 or 45
Premature ovarian insufficiency is more common than thought. How it's recognised, why missing hormones should be replaced and what it means for having children.
Bones and strength training after menopause
Why women lose bone quickly in the first years after menopause, what exercise does about it and why strength training works at 60 just as well as at 30.
Training & nutrition
How much protein do you need if you train?
1.2 g? 2 g? What the German Nutrition Society recommends for everyone, what the sports nutrition society gives for people who train, and what Rhythmus calculates with.
Training during your period: what works and what you can adjust
Pause or keep going? What the evidence says about performance during your period, how to adjust sensibly and when pain should be checked.
Cycle-based training: what is really supported by evidence
“You build more muscle in the follicular phase” – a 2026 randomised trial tested exactly that. The evidence on cycle-based training, with sources.
When your period stops, it's not a success
A missing period is often mistaken in sport for a sign of good form. What relative energy deficiency means, how to recognise it and when to see a doctor.
Calculating calorie needs: what the number can and can't do
Calculating calorie needs for women: the Mifflin-St Jeor equation step by step, a worked example, how accurate it is and what the cycle changes. With sources.
Meal breaks and snacks: what happens in the body and what the evidence says
Do meals need breaks in between? What the gut does between two meals, what studies find on the number of meals and on snacking, and when fasting is not a good idea. With sources.
About cycle apps
What a “free” period app really costs
Most free period apps make money from ads, subscriptions or data. How these models work, how to check them yourself and how Rhythmus is funded.
What Flo Premium and Clue Plus unlock
Flo and Clue are listed as “Free”, yet both sell a subscription. Which features are free and which only Premium unlocks, based on what the companies list themselves.
How we rate studies
What “established”, “small effect” and “not supported” mean in Rhythmus, what we look at in a study, why we don't use impact factors and where our rules reach their limits.
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