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Lifting on your period: what changes and what does not

By Chris Ayers 6 min read

Lifting weights on your period is the question that comes up more than any other, so it deserves a straight answer. The short version: for most people, training during your period is fine, the measured drop in strength is small enough that researchers call it trivial, and what actually changes a session is how you feel that day, not what day it is. The longer version has some useful detail in it.

What the strength data says

The first days of your period are the early follicular phase, when estrogen and progesterone are low. If any phase were going to hurt performance, this would be the one, and the research does point here, faintly.

One of the largest reviews on the subject, by McNulty and colleagues in Sports Medicine in 2020, included 78 studies of exercise performance across the cycle. Its finding was that performance “might be trivially reduced during the early follicular phase” compared with all other phases. Trivially is the authors’ word, and they rated the quality of the evidence as low. Their conclusion was that general rules could not be formed, and they recommended a personalised approach based on each woman’s own response.

A 2026 meta-analysis by Britton and colleagues in Reproduction and Fertility looked at a smaller and stricter set: five studies of elite or well-trained athletes where the phase was confirmed with blood hormones rather than guessed from a calendar. Comparing the early follicular and mid-luteal phases, they found no statistically significant differences in VO2 max, with small, non-significant decreases in the early follicular phase. They allowed that “minor or individual-specific effects” may exist. One caution: VO2 max is an endurance measure, not a strength one, so this paper tells you about aerobic capacity on your period, not about your squat.

Put the two together and you get a consistent picture. Something small may be happening in the period days. It is small enough that most studies cannot see it, and the ones that do see it see a dip, not a wall.

What actually changes: symptoms

Here is where the real variable lives. In 2021, Bruinvels and colleagues published a study in the British Journal of Sports Medicine of 6,812 exercising women, recruited through the Strava app, who were not on combined hormonal contraception. The most common symptoms they reported were mood changes or anxiety (90.6 percent), tiredness or fatigue (86.2 percent), stomach cramps (84.2 percent) and breast pain or tenderness (83.1 percent). The authors’ summary was blunt: “menstrual cycle symptoms are very common in exercising women.”

A higher score on the authors’ symptom index was linked to a greater likelihood of missing or changing training, with an odds ratio of 1.09. The women said these symptoms got in the way of exercise and of work. That points at the thing that matters. In this survey, symptoms like cramps, tiredness and low mood were what women linked to missed or changed sessions.

So the honest answer to “should I lift on my period” is that the phase itself seems to matter very little, and how you feel that day matters more.

Here is how I built Ferrabelle around that, and I want to be exact about it. You log symptoms in the same app as your lifts, so over a few cycles you can see whether the cramps line up with the sessions that went badly. The daily Fe Score uses your phase plus your own sleep, stress and recovery, so two women on day 2 get different scores if their nights were different. It does not read symptoms. A woman with no cramps on day 2 and a woman curled up on the couch on day 2 are in the same phase, but they are not having the same day, and your log is where that difference shows up.

Period pain, and when it is more than that

The NHS describes period pain simply: it happens when the womb tightens during your period, and it is often a normal part of the menstrual cycle. Their self-help list includes heat, massage, gentle exercise like yoga, swimming, walking or cycling, and over-the-counter painkillers. I am not going to tell you which painkiller or how much, because I am a software developer and that is not my place. The NHS page has the detail.

Notice that gentle movement is on the list. Nothing in the research above says to stop moving during your period, and the NHS lists gentle exercise as one way to ease period pain.

The NHS also gives a clear list of when to see a GP: if your periods become more painful, heavier or irregular, or if the pain stops you doing your usual activities. If the pain is severe or worse than usual and painkillers have not helped, they say to ask for an urgent GP appointment or get help from NHS 111. Outside the UK, that means your own doctor or urgent care line. That last line is the important one for lifters. Pain that stops you training is not something to push through or log around. It is something to mention to a doctor.

A practical way to think about it

Train on your period if you feel like training. Nothing in the research above says you should not. If cramps or fatigue are heavy, take the lighter day, and write down why. The point of logging is not to build a perfect record. It is to find out, over three or four cycles, whether your period days have a pattern worth planning around, or whether they are just days.

That is a boring answer. From the papers above, I think it is the true one.

This is general information, not medical advice. Talk to your doctor about your own health.

Ferrabelle is in a closed test on Google Play right now. If you want your period, your symptoms and your lifts logged in one place, you can join at ferrabelle.com/testers.

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