Why is my heart rate higher in the week before my period?

What happens in the luteal phase

The second half of your cycle, after ovulation, is called the luteal phase. Progesterone then takes the lead, and that hormone does more than prepare the uterus. It raises your body temperature by a few tenths of a degree, it speeds up your breathing and it shifts the balance in your autonomic nervous system towards activation.

Your heart notices. In research on women with a natural cycle, resting heart rate in the luteal phase sits on average two to five beats higher than in the follicular phase, the first half. Heart rate variability (HRV), the small variation between successive heartbeats, is lower then. Both are an ordinary consequence of the hormone, not of bad nights or too much sport.

The highest values fall in the days just before the period. As soon as it starts, progesterone drops quickly and your resting heart rate drops with it, often within a few days. Whoever looks at their own curve over a few cycles can see the pattern return: a slow rise in the second half, a fall on the first day.

Why your watch reads this as poor recovery

A recovery score compares tonight with your own baseline of the past weeks. A higher resting heart rate and a lower HRV are, in that comparison, the signs of stress, illness or too much load, and that is what the score is built on. It does not know your cycle, and so it reads the luteal phase as a week in which things are going worse.

That is not measured wrongly; it is interpreted wrongly. Your body really is doing more work in that week, and your capacity to recover really is a little smaller. But it is an expected, recurring shift with a known cause, and not a signal that you are doing something wrong. The difference lies in what you do with it: a real warning asks for less, a luteal week asks for recognition.

Read it against your own cycle, not against a norm

How big the shift is for you, nobody can take from a table. For one woman it is one beat, for another six; one also notices it in how sessions feel, another not at all. Hormonal contraception changes the picture as well: on the pill there is no progesterone peak of your own, and much of the pattern disappears or shifts.

That is why the useful comparison is not with a norm but with yourself: the luteal week of this cycle against the follicular week of this cycle, and the luteal week of this cycle against that of the previous one. Only when a pattern returns over several cycles is it your pattern. One high week may also simply have been a cold.

In practice: write down the first day of your period, and after three or four cycles look at your resting heart rate and HRV per cycle day. That is all that is needed to know whether it does something for you and how much.

Training in that week

There is no general rule that says you should train less in the luteal phase. What there is: a slightly smaller margin. You cool less well, so heat weighs heavier; your recovery is a little slower, so a second hard session shortly after the first hits harder. Hard work is fine, with a little more attention for the day after.

In that week, use your own feel as a measure alongside heart rate. A session at the same heart rate as last week is, in the luteal phase, a little easier than it looks, because the heart rate itself is higher; a session at the same pace is then a little harder. Steering by how hard it feels keeps both effects in view.

Sleep is often less deep in this phase, and the higher temperature does not help. A cooler bedroom and a little more time in bed do more here than in the rest of the month.

When it is more than your cycle

A resting heart rate that stays high after your period has started, or that climbs further from cycle to cycle, does not fit the luteal phase alone. The same goes for a heart rate that sits structurally higher at the same effort than before, unusual tiredness or breathlessness. Anaemia from iron deficiency is relatively common in women with heavy periods and gives exactly that picture.

This article is not medical advice. With complaints that do not move with your cycle, or a period that stays away while you train a lot, your doctor is the place to start.

What Trimetra does with this

Cycle tracking in the app is opt-in. If you record the first day of your period, the app derives your cycle day and your phase from your own cycle length and shows them alongside your sessions and your recovery. There are no fixed training rules per phase.

The app compares your resting heart rate and your HRV with your own baseline of the past weeks. Only once you have logged enough over several cycles does it check whether your phase demonstrably says something for you, for example whether comparable easy sessions in your premenstrual week structurally feel harder. That is context for what you see; it does not override your plan, and you decide what to do with it.

Frequently asked questions

Trimetra follows your cycle only if you switch it on, reads your resting heart rate and HRV against your own baseline and only says something about your phase once your own cycles show it. An average from the literature never becomes your explanation.