Why am I so tired before my period, and what can I do at work?

Nobody knows exactly why it happens. Health sources point to the rise and fall of hormones after ovulation, and to shifts in serotonin, a brain chemical tied to mood, energy and sleep. PMS is also very common: Mayo Clinic estimates that up to three in four people who menstruate have had some form of it.

At work, the tiredness rarely shows up alone. Sleep may be lighter or longer than usual, focus may slip, and patience may run shorter. The same calendar that felt fine two weeks ago now feels like too much. The useful part is the timing. Tiredness that arrives on schedule is tiredness you can plan for.

Find your tired window first

Plenty of things drain you: a bad week, a cold, a toddler who will not sleep. To know whether your cycle is part of it, keep short notes for two or three cycles. Rate your energy from one to five each day, note how you slept, and mark the first day of each period.

Then look back. If the low days bunch up in the same stretch before each period, you have found your window, and it is often a similar length each month. If the low days are scattered everywhere, something else is likely doing more of the work, and that is worth taking to a doctor.

Move the heavy lifting out of the window

Once you know roughly when the tired days land, look at the calendar for those dates now, while you still have room to change it.

• Do the hard prep earlier. Write the deck, the report or the performance review the week before, so the tired day is only for delivering it.
• Move what can move. Internal check-ins, brainstorms and optional calls often slide by a few days without anyone minding. You do not have to give a reason.
• Keep your best hours for the one thing that matters. On a low day, pick one task that needs real energy and put it in the time you usually feel sharpest.
• Fill the rest with work that runs on autopilot: inbox, expenses, scheduling, tidying a shared doc.

Make the tired days lighter to carry

Some days in the window will be full no matter what. A few small changes make them easier.

• Leave ten or fifteen minutes between meetings. Back-to-back calls drain you faster when you are already low.
• Turn a sit-down call into a walking one if your camera does not need to be on.
• Take a short walk outside at lunch. Daylight and a little movement may help with the afternoon slump.
• Say no to the optional extras that week: the after-work drinks, the extra committee, the favor that can wait.
• Write a three-line plan for each important meeting the day before, so you are not relying on a tired memory.

Protect your sleep before it runs out

Sleep problems are part of PMS for a lot of people, and a short night makes the tiredness worse. MedlinePlus suggests getting plenty of sleep throughout the month, keeping the hour before bed quiet, and getting regular exercise across the month, which can make PMS symptoms less severe.

In practice, keep the evenings in your window light. Move late dinners and late calls with other time zones to earlier in the month if you can. An evening you blocked a week ago is much easier to protect than one you are already too tired to argue for.

When to talk to a doctor

Check in with a doctor if the tiredness does not get better with these changes, if it does not lift after your period starts, or if it gets in the way of work and home life. The same goes if the tiredness comes with feeling very sad, hopeless or easily frustrated. Bring your notes. A few months of daily ratings make that conversation shorter and clearer.

How Maeve does it

Maeve reads your calendar and shows your likely hard days next to the meetings you already have, two weeks ahead. Each day it gives you two suggestions tied to your real meetings, like writing Thursday’s update on Monday or keeping Wednesday evening clear. You add the ones you want. Maeve never edits, moves or deletes a meeting, and it does not use AI: suggestions come from rules.

A quick daily check-in teaches Maeve when your own tired days tend to land, and after a few cycles it can turn what you logged into a doctor report. Your data is end-to-end encrypted, so Maeve cannot read it.

Maeve is not a medical device and does not diagnose or treat any condition. If your symptoms worry you, talk to a doctor.