Your doctor will likely ask you to track your symptoms across two to three cycles, as diagnosis is based on symptom patterns, severity, and how they impact your daily life across multiple cycles. In some cases, symptoms may become more severe over time, so it’s important to monitor patterns across cycles.

You should also consult your doctor if symptoms don't resolve after menstruation begins, or worsen over time, as this could indicate conditions like endometriosis or polycystic ovary syndrome (PCOS), which is characterised by small ovarian cysts, irregular menstrual cycles, insulin resistance, and weight gain.

What Age Does PMDD Start?

While PMDD can start at any age, onset is common any time from your mid-twenties to mid-thirties, with a number of risk factors that can contribute to it, including:

• Hormonal changes—particularly as you approach perimenopause.
• Changes in neurotransmitters like serotonin (which regulates your mood) and the way your brain responds to it, which seem to happen in the days before your period.
• Chronic stress overload caused by ongoing life pressures or other existing challenges.
• Having a personal history of mood or anxiety disorders.

What Is Menstrual Rage (and Is It Normal?)

You know that intense, often irrational anger that can sometimes come on suddenly before your period? That’s menstrual rage, and although it’s not a formal medical term, it might sound familiar.

It broadly covers the bursts of irritability, irrational rage, and feeling of being on a “short fuse” that are common in PMS.

If your menstrual rage intensifies, and this pattern repeats predictably across cycles, it could indicate PMDD.

To recognise what’s “normal” for you, it helps to understand what’s happening to your body during each phase of your cycle.

The Menstrual Cycle Explained

The average menstrual cycle length is 28 days, but this varies greatly from one person to another—“average” for you could mean as short as 21 or as long as 35 days.

The changes you notice throughout the month are the result of the ebb and flow of four key hormones:

• Oestrogen: Prepares your body for ovulation and pregnancy during the first half of your cycle. After ovulation, it maintains the thickness of the uterine lining to support the chance of pregnancy, then drops if pregnancy doesn’t happen. It also makes your brain’s receptors more responsive to serotonin, a mood-balancing hormone.
• Progesterone: Helps prepare your uterine lining for a possible pregnancy after ovulation. If pregnancy doesn’t occur, it drops, triggering your period. As progesterone levels rise and fall during the luteal phase, many people experience irritability, anxiety, and aggression.
• Follicle-stimulating hormone (FSH): Signals to the ovary to mature an egg and release oestrogen.
• Luteinising hormone (LH): Triggers ovulation and the production of progesterone.

Changing levels of oestrogen and progesterone throughout the month are the reason you might feel overwhelmed with emotions before your period.

Phase 1: Menstrual Phase (Days 1–5)

Your menstrual cycle starts on the first day of your period. As your uterus sheds its lining, both oestrogen and progesterone are at their lowest levels, which can leave you feeling emotionally sensitive, tired, irritable, and lacking interest in things you normally enjoy.

This is usually when your energy is at its lowest, and you might struggle to focus, socialise, or push through demanding tasks—or crash out if you try.

If possible, this is the phase to clear your schedule and book a hot date with your couch. Going to bed early and incorporating gentle movement like walking or yoga can also support your mood and energy levels.

During menstruation, heart rate variability (HRV) is often higher compared to the premenstrual phase, while skin temperature tends to be relatively lower, reflecting shifts in autonomic balance and thermoregulation as hormone levels change.

Phase 2: Follicular Phase (Days 6–14)

As your period comes to an end, oestrogen rises, and your body starts preparing for ovulation. During this phase, many women report relatively better mood, more energy, and improved mental focus compared with the luteal (premenstrual) phase.

This is usually when you’re at your most social and motivated, making it a good time for decision-making, creative work, and socialising.

It’s also when you should lean into the more demanding tasks on your to-do list, start new projects, and schedule meetings or collaborative work—just be careful not to write any cheques your menstruating self won’t be able to cash.

During the follicular phase, HRV tends to be higher compared to the luteal phase, while skin temperature tends to remain stable but low.

Phase 3: Ovulation (Days 14–16)

In the middle of your cycle, your ovary releases an egg, oestrogen peaks, and LH surges.

You may notice more confidence, a higher libido, and feeling more sociable and expressive—but hormonal changes can also make you emotionally sensitive or reactive.

This is usually when you’re at your most outgoing, making it a good time for connection and communication, but be mindful that your emotions might feel heightened.

During ovulation, HRV often drops, while skin temperature tends to be at its lowest point in your cycle.

Phase 4: Luteal Phase (Days 17–28)

After ovulation, oestrogen drops, and progesterone rises to prepare for a possible pregnancy. If pregnancy doesn’t occur, progesterone drops too, which is why many people feel more emotional in the days before their period.

You might notice gradual shifts in energy, appetite, and sleep patterns, along with increased anxiety, irritability, sadness, and anger.

You could also feel more sensitive to the stress of daily demands, so that even small or routine pressures can feel heavier or more overwhelming than usual.

During the luteal phase, HRV usually drops while skin temperature reaches its highest point in the cycle, reflecting higher progesterone and sympathetic nervous system activity (a.k.a. the “fight or flight” response).

How to Manage Mood Swings Before and During Your Period

“There are four research-backed lifestyle changes that can help reduce the symptoms associated with PMS”, explains Joana. Here’s how implementing them can help you stay more emotionally balanced before and during your period.

1. Double Down on Your Sleep Routine

Around 25-33% of people who menstruate report that their sleep gets noticeably worse in the days leading up to their period—which, in turn, can exacerbate the symptoms of PMS.

Sleep-cycle studies consistently recommend keeping a consistent bedtime routine as a way to reduce the effects of hormonal changes on your sleep quality.

2. Reduce Stressors before Your Period

Studies show that many people who menstruate experience higher perceived stress before their period starts, and that prioritising self-care and self-compassion during this time can reduce PMS symptoms.

Being aware of where you are in your cycle can help you take steps to support yourself. When you enter the late-luteal phase, you can protect your energy by lowering expectations and commitments, and choosing nourishing routines like more rest or lighter work.

3. Move Your Body (Gently)

A 2021 study found that 71% of people who menstruate avoid working out before and during their period, with more than half citing pain and cramping as the main reason.

But light-to-moderate activity—like yoga, walking, or stretching—during the luteal phase has actually been shown to reduce PMS symptoms, while high-intensity training during this time can amplify them.

4. Reduce Stimulants

Caffeine and alcohol both increase sympathetic nervous system activity, which is already elevated in the luteal phase. Because both can increase symptom severity, it’s often a good idea to reduce or avoid them in the days before and during your period.

How Tracking Can Help You Manage Mood Swings During Your Cycle

Mood swings don’t appear out of nowhere—they follow patterns linked to your physiology. The challenge is spotting those patterns.

Perhaps you feel overwhelmed “sometimes”, sleep badly “some nights”, or snap at people “for no reason”—but without a clear view over time, it’s difficult to connect those moments to where you are in your cycle.

That’s why tracking matters—when you start paying attention to signals like sleep quality, stress responses, and mood, you can begin to see how your body shifts in repeatable cycles.

Over time, this makes it easier to anticipate when you’re likely to feel more sensitive, plan your schedule around your energy and emotional capacity, and step in earlier with the support your body needs.

But doing this manually across notes, apps, and memory is difficult to sustain—and even harder to interpret.

That’s where NOWATCH’s Cycle Patterns feature comes in.

Unlike other wearables, it displays your cycle data alongside stress biomarkers like HRV and skin temperature, creating a detailed overview of how stress and your cycle influence each other—so you can adjust your schedule, expectations, and energy before symptoms hit.

With the Check-In feature, you’ll receive a reminder to log your mood a couple of times a day. Logging consistently over time can help you see how your body and mind respond to stress during different cycle phases.

Because once you see the pattern, it stops being random—and starts feeling manageable.