You can train and compete well at any point in your cycle. Performance may dip by a tiny amount in the first few days of your period, but the difference is too small to change what you can do. There isn't enough evidence to say you should plan your training around your cycle.
What you feel is still real
Average results don't tell you how you feel. Cramps or heavy bleeding can make a session feel harder, even if your body is capable of the same performance. The best guide is your own pattern. Tracking how training feels alongside your cycle for a few months can show you whether certain days are tougher for you.
What about cycle syncing?
You may have seen plans online telling you to lift heavy in one phase and only do gentle exercise in another. So far there's no clear evidence that your cycle changes how strong you are, or how well your muscles respond to strength training. Those plans aren't backed by good science yet. If one helps you feel more in control, that's fine, but you don't need to follow one.
Making training easier on your period
Treat pain early. Anti-inflammatory painkillers or heat can help, and regular exercise can lower period pain over time (see our article on period pain).
Choose products you trust to move in. Many athletes prefer a tampon or cup for swimming and period pants as backup.
Eat enough. Your body needs fuel for training and for your cycle to work normally.
Watch your iron. You lose iron in period blood, and low iron can leave you tired and slower to recover (see our article on heavy periods).
When your period stops
If your periods stop or become irregular while you're training a lot, it can mean you're not eating enough for the energy you use. Experts call this Relative Energy Deficiency in Sport, or REDs. Without enough energy, your body cuts back on things it doesn't need to survive, including your cycle. Over time, REDs can weaken your bones and affect your mood and performance. Losing your period is never a sign that you're training well.
When to see a doctor
Book an appointment if:
your periods stop for 90 days or more, or become irregular after being regular
you've had a stress fracture or keep getting injured
you feel tired all the time and your performance is dropping
period pain stops you training
A sports doctor or sports dietitian can help you work out whether you're eating enough for your training.