Tracking your cycle gives you a clearer understanding of your body — what’s normal for you, when things shift, and why you feel the way you do across the month. Most women notice predictable patterns in energy, mood, sleep, and appetite tied to each cycle phase.

When you can see those patterns, you can work with your body rather than against it — an approach often called cycle syncing. That might mean planning demanding work and social commitments for the first half of your cycle, when energy tends to be higher, and building in more rest through the luteal phase (the second half).

The benefits of tracking build as you go:

• Predict your period and ovulation with growing accuracy as you track more cycles.
• Spot patterns in mood, energy, sleep, and symptoms.
• Notice irregularities early — useful for fertility, perimenopause, or hormone changes.
• Make decisions about exercise, nutrition, and rest that suit your phase.
• Build a record you can share with your GP or specialist.

This is the reason a period tracking app is more useful than memory alone. Your cycle is also a window into your wider health — stronger PMS can show up when the body is under stress, for example. That’s why the menstrual cycle is often called the body’s fifth vital sign: the American College of Obstetricians and Gynecologists recognises it alongside heart rate, blood pressure, temperature, and breathing.

Ovulation is the release of a mature egg from one of your ovaries. It usually happens once each cycle, around day 14 of a 28-day cycle — though the exact timing varies from woman to woman, and from one cycle to the next.

Signs and symptoms of ovulation include:

• Cervical mucus that becomes clear, stretchy, and egg-white in texture — the most reliable real-time sign.
• A small rise in basal body temperature (BBT) of around 0.3–0.5°C the day after ovulation, which confirms it has happened.
• A positive ovulation predictor kit (OPK), which detects the LH surge 24–36 hours before ovulation.
• Mild cramping on one side of the lower abdomen (sometimes called mittelschmerz).
• A noticeable lift in energy, libido, and mood around mid-cycle.
• A heightened sense of smell or clearer skin (less reliable, but reported by some).

You’re only fertile for a short window each cycle. The fertile window is the five days leading up to ovulation plus ovulation day itself — your most fertile days. Sperm can survive in the reproductive tract for up to five days, but the egg is only viable for around 24 hours after release.

No single sign is definitive on its own. Tracking a few of them together, across a few cycles, gives you the clearest picture of when you ovulate.

The menstrual cycle has four phases, each with its own hormonal pattern — and its own effect on how you may feel:

• Menstrual phase: days 1 to 5 (approximately). Your period. Oestrogen and progesterone are at their lowest. Energy can be low — a natural time for rest and reflection.
• Follicular phase: days 6 to 13 (approximately). Oestrogen rises as follicles develop in the ovaries. Energy, mood, and motivation typically lift — a natural time for new projects and creativity.
• Ovulatory phase: around day 14 (mid-cycle). Oestrogen peaks and a surge in luteinising hormone (LH) releases an egg. Energy, confidence, and libido are often at their highest. This is the fertile window.
• Luteal phase:days 15 to 28 (approximately). Progesterone rises, then falls if pregnancy doesn’t occur. Energy typically declines through the phase, and many women experience PMS in the final days before their next period.

Phase lengths vary — these are averages based on a 28-day cycle. Your own pattern is what matters.

The menstrual cycle is the monthly hormonal pattern that prepares the body for a possible pregnancy. It’s counted from day one — the first day of your period — and ends the day before your next period begins.

Cycles vary from woman to woman, but a typical cycle lasts 28 to 30 days, and anywhere from 21 to 35 days is considered normal. It’s driven mainly by oestrogen and progesterone, with follicle-stimulating hormone (FSH) and luteinising hormone (LH) triggering ovulation. The cycle is divided into four phases: menstrual, follicular, ovulatory, and luteal.

Halo is built for the whole arc of your cycling life, not one slice of it. Whatever stage you’re in, the app adapts to you when you set up your profile, and Luna’s guidance shifts to match.

Halo supports you through:

• Your early cycling years, as you learn what’s normal for you.
• The reproductive years — whether you’re simply tracking, trying to conceive, or coming off hormonal contraception.
• Life after a baby, as your cycle finds its rhythm again.
• Perimenopause, when cycles become less predictable and symptoms shift.
• Menopause and beyond, where cycle-aware support doesn’t simply fall away.

It also holds up when your cycle doesn’t follow the textbook — with conditions like polyendocrine metabolic ovarian syndrome (PMOS, formerly PCOS) or naturally irregular cycles. Every stage is treated as whole in itself, not a phase to get through on the way to another.

Cycle syncing is the practice of adjusting how you eat, move, work, and rest to match the changing phases of your menstrual cycle, rather than expecting the same energy from yourself every day.

Your hormones shift across the month, and your energy, focus, and mood often shift with them. Working with that rhythm rather than against it can feel more sustainable than treating every day the same.

In broad terms, many women find:

• Menstrual phase (days 1–5): energy is often lower — a natural time to rest and keep things gentle.
• Follicular phase (days 6–13): energy and focus tend to rise — often a good window for demanding work and new ideas.
• Ovulatory phase (around day 14): energy and confidence are often at their highest — a natural time to connect and take on outward-facing things, from socialising to the work that benefits most from confidence.
• Luteal phase (days 15–28): energy gradually winds down — steadier work and more rest tend to suit the days before your period.

Cycle syncing exercise means matching movement to each phase — gentler movement like walking or yoga during your period and luteal phase, and higher-intensity training when energy peaks in the follicular and ovulatory phases.

Cycle syncing nutrition means eating to support each phase. Practices like seed cycling — rotating specific seeds across the two halves of your cycle — are one popular approach.

There’s no single right way to do it, and your own pattern is what matters. Halo is built to make that pattern visible, so cycle syncing becomes something you can see rather than guess at.

Halo of Health has two tiers:

Halo Glow: Free, always. The cycle-tracking app, with personalised AI coaching built in — cycle and lifestyle tracking, Luna by text or voice, daily check-ins and insights, voice logging and a personal journal, wearable sync, predictions and patterns, and support for every life stage.

Halo Circle:£7.99 / month (price confirmed at launch). Our membership tier — wellness practices including meditations, breathwork and EFT, monthly live Q&A sessions with Stephanie and invited specialists, early access to new products, practitioner circles, and our annual magazine, posted to your door.

Halo Glow is free for everyone; Halo Circle adds community, content, and closeness.

Yes. Your data is yours.

Halo is built by Seed Cycle Limited, a UK company that’s ICO-registered and GDPR-compliant. We never sell your data, and we never share it with advertisers. You can export or delete everything at any time.

Privacy of women’s health data matters, particularly given the broader landscape of how period tracking data has been used elsewhere. Halo stores your data encrypted, in the UK, with explicit consent at every step.

Halo of Health focuses on the whole woman, not just the cycle. While most apps track period dates and predict ovulation, Halo brings together four things they don’t:

• A science-led AI companion called Luna that learns your cycle and answers your questions by text or voice.
• Phase-aware personalisation, so the guidance you receive shifts with your menstrual, follicular, ovulatory, and luteal phases.
• Support across every life stage, from your first cycles through perimenopause and beyond.
• Holistic wellness — nutrition aligned to your phase, plus movement, sleep, and a wellness library covering the seed cycling protocol, nervous system support, and more.

Halo is built for women who want depth and intelligence in their cycle support.

Luna is your AI companion within Halo of Health — a science-led guide who knows your cycle and answers your questions in a friendly, conversational way.

Whether you want to log your day by voice — “feeling tired today, started my period, slept seven hours” — ask “why am I feeling flat this week?”, or get phase-specific advice, Luna meets you where you are. She works by both text and voice, and her responses are grounded in evidence rather than guesswork.

Think less chatbot, more knowledgeable friend.

Yes — perimenopause and menopause are part of Halo’s core design, not an afterthought.

In perimenopause, cycles often become unpredictable — which is exactly when a clear record becomes most useful. Halo lets you track what shifts in this stage alongside your cycle: hot flushes, sleep, mood, energy, and changes in flow. Over time that builds a picture of your own pattern, not a textbook one.

It’s also a record you can take to a GP with menopause training — helpful if you’re weighing up HRT or other support, where your own symptom history makes the conversation easier.

And it doesn’t stop at your last period. Cycle-aware support — symptom tracking, Luna’s guidance, and resources tuned to this stage — carries on through menopause and beyond, when many apps stop being relevant.

Halo of Health launches in Summer 2026 in the UK.

Halo Glow is free for everyone. Waitlist members are the founding community — the first to use the app, the first inside the shop, and the first inside the Halo Circle.

Join the waitlist at haloofhealth.com.