Something I’m incredibly passionate about is helping people understand their circadian rhythms. Many people aren’t even aware it’s a thing, let alone that it impacts their day-to-day wellbeing and overall quality of life. But it really does.
If we don’t know about something, we can’t change or support it. That’s why understanding your circadian rhythm is the first step to mastering it.
What is the Circadian Rhythm?
Your circadian rhythms are 24-hour cycles that are part of your body’s internal clock, running in the background to carry out essential functions and processes. One of the most important—and probably the most well-known—circadian rhythms is the sleep-wake cycle, which follows the rhythms of cortisol and melatonin across a 24-hour period.
These rhythms are governed by light and dark cues, which influence the hypothalamus in your brain to signal the release of two key hormones:
- Cortisol: An energy-mobilising hormone that peaks in the morning in response to daylight.
- Melatonin: A hormone that rises in response to darkness at night, facilitating restorative sleep.
In a healthy person, cortisol peaks within 30-45 minutes of waking up—known as the cortisol awakening response (CAR)—and gradually tapers down throughout the day, reaching its lowest point at night as melatonin rises.
I use the DUTCH test in my practice to measure the CAR and the daily rhythm of cortisol and melatonin.
Why Your Circadian Rhythm Matters in Perimenopause
Circadian disruption is a huge factor in almost all areas of health and wellbeing, including hormone health and your experience of perimenopause. It affects your HPA axis (the body’s stress response system – the communication link between the hypothalamus and pituitary in the brain and the adrenal glands), impacting the nervous system, blood sugar regulation, insulin control, cardiovascular health, thyroid health, and more.
During perimenopause, your hormonal landscape is already shifting. If your circadian rhythm is out of alignment, you’re likely to feel it even more. Research shows that nearly half of all genes expressed daily have some sort of circadian rhythm, impacting systems throughout your body. If your rhythm is off, this creates metabolic inefficiencies that affect everything from energy levels to hormone balance.
The Cortisol Connection
We could even call the circadian rhythm the cortisol rhythm because it’s all about the pattern of cortisol across the day. Cortisol peaks in the morning, triggered by daylight hitting your optic nerve, and then gradually declines throughout the day.
But if you’re not getting enough daylight in the morning—or you’re getting too much blue light from screens at night—your cortisol rhythm can be thrown off. This misalignment leads to disruptions in energy, mood, sleep, weight management, and even menstrual and hormonal cycles.
The impact is significant. Cardiovascular risks, insulin resistance, metabolic health issues, and more are linked to circadian disruption. Even if you’re not a shift worker or constantly changing time zones, an out-of-sync circadian rhythm can lead to these risks.
How to Master Your Circadian Rhythm
The good news? You can take control of this rhythm for yourself. This is known as circadian entrainment, and it’s a big part of the work I do with clients. Here are my top tips for training your circadian rhythm:
- Daylight Exposure
- Get daylight exposure on your eyes within 20-30 minutes of waking up:
- 3 minutes on sunny days
- 10 minutes with some cloud
- 20-30 minutes on overcast days
- If it’s dark when you wake up (especially in winter), consider using a full spectrum light box (10,000 lux).
- Get daylight exposure on your eyes within 20-30 minutes of waking up:
- Dim Lighting in the Evening
- Start dimming the lights at home from about 7 pm, gradually moving towards darkness as bedtime approaches.
- Blue-light blocking glasses can be helpful for evening screen time, as blue light stimulates cortisol, which you want to be reducing in the evening.
- Meal Timing and Composition
- Break your fast within an hour of waking with at least 30g of protein.
- Finish dinner at least 2 hours before bedtime to allow cortisol to lower and melatonin to rise.
- Include complex carbohydrates (like sweet potato, quinoa, or brown rice) with your evening meal to prevent blood sugar drops during the night.
- Caffeine Timing
- Delay caffeine intake for 90 minutes after waking to support your natural cortisol awakening response.
- Avoid caffeine after 11 am to allow cortisol to lower naturally by bedtime.
- Consistency is Key
- Maintain a consistent sleep and wake time, even on weekends.
- Your circadian rhythm thrives on routine, so avoid drastic changes that can throw off your cortisol pattern.
The Perimenopause Fatigue Connection
Many women in perimenopause feel a “jet lag” sensation even without changing time zones. This is a clear sign that the circadian rhythm needs support. After 40, our rhythms are more sensitive, making them easier to fall out of sync.
If your circadian rhythms are off, the HPA axis (the body’s stress response system) senses this as a major stressor, adding more pressure to an already challenged hormonal system during perimenopause. This can worsen symptoms like:
- Brain fog, focus, and memory issues
- Headaches, hot flushes, and night sweats
- Mood swings and anxiety
- PMS, breast pain, and heavy periods
By mastering your circadian rhythm, you can significantly reduce the intensity and frequency of these symptoms.
Taking Control of Your Rhythm
I always start with circadian entrainment in my practice because it’s foundational to everything else. It sets the stage for balanced hormones, steady energy levels, better sleep, and overall metabolic health.
If you’re feeling out of sync, especially during perimenopause, it’s time to take back control of your rhythm. Simple daily practices—like getting daylight first thing in the morning, eating at regular times, and minimising blue light exposure at night—can make a world of difference.
Want to learn more or need support with your circadian rhythm and perimenopause symptoms? Feel free to reach out or book a session. Mastering your circadian rhythm might just be the missing piece to vibrant health.
Ready to Take the Next Step?
If you’re ready to optimise your circadian rhythm and take control of your perimenopause experience, get in touch or book a session today. Let’s work together to realign your rhythms and empower your health journey.
