Circadian Rhythm: Why your lifestyle is out of synch with your body clock
- Gemma Westfold
- Apr 20
- 5 min read
Updated: Apr 22
At some point, this became normal:
Staying up past midnight scrolling on your phone. Watching another episode on Netflix even though you feel tired. Eating most of your food late in the evening. Waking up feeling unrefreshed, dragging yourself out of bed and relying on caffeine to get going.
It feels like modern life. But biologically, it is a mismatch.
Your body runs on a 24 hour internal timing system called the circadian rhythm. This system regulates sleep, metabolism, hormones, digestion and inflammation. It is not just about how much you sleep, but when everything in your day happens.
When your routine drifts later and becomes inconsistent, the whole system starts to lose coordination.
What our bodies are designed for
Humans are diurnal. We are built to be active during daylight and to rest at night.
This rhythm is controlled by the brain’s master clock, the suprachiasmatic nucleus. It responds primarily to light and sends timing signals throughout the body.
In short, our biology expects a predictable daily pattern:
Light in the morning
Food during the day
Movement in daylight hours
Darkness and rest at night
When this pattern is consistent, the body regulates itself efficiently. Sleep comes more easily, energy is more stable, appetite is better controlled and recovery processes work as they should.
Where we are going wrong with modern life
Most people are now living in a way that pushes directly against this system.
Artificial light extends the day late into the night. Screens keep the brain stimulated. Morning light exposure is minimal. Meals are delayed and often concentrated in the evening. Daily routines shift from one day to the next.
The brain interprets all of this as mixed signals.
Light late at night delays melatonin, the hormone that prepares you for sleep. Lack of morning light means your body clock is never properly reset. Over time, your rhythm shifts later and becomes unstable.
This is why it can feel difficult to fall asleep at night but equally hard to wake in the morning.
The Wired and Tired Pattern
Many people describe feeling exhausted but unable to switch off.
This state often comes from circadian disruption rather than simply stress or poor sleep habits.
When your internal clock is delayed:
You feel more alert late at night
Sleep onset becomes harder
Sleep quality is reduced
Morning energy is low
The result is a cycle of fatigue, stimulation and further disruption.
Caffeine, screens and irregular routines keep reinforcing the pattern.
Why Late Eating Works Against You
Timing of food matters as much as the food itself.
Your body is more metabolically active earlier in the day. Insulin sensitivity is higher in the morning, meaning you handle carbohydrates more efficiently.
In the evening, the body naturally becomes more insulin resistant as it prepares for rest.
When most of your food intake is pushed later:
Blood sugar control worsens
Fat storage increases
Appetite regulation becomes less stable
Sleep can be disrupted
Late evening eating is often linked to stronger cravings and a sense of reduced control. This is not just behavioural. It is driven by biology.
What We Can Learn From Children
A useful comparison I use with clients is how babies and toddlers function.
They follow consistent rhythms. They wake at similar times, eat regularly and sleep best when their routine is stable.
If a toddler misses a nap, they do not sleep better that night. They become overtired, overstimulated and harder to settle.
Guess what? Adults respond in a similar way when sleep and daily rhythms are disrupted.
The difference is that adults push through fatigue rather than responding to it which often leads to feeling wired late in the evening despite being tired throughout the day.
Circadian Disruption and Health
Research has consistently shown that disrupted circadian rhythms are linked to long term health issues.
Shift workers, who experience the most extreme disruption, have higher rates of:
Type 2 Diabetes
Obesity
Cardiovascular disease
Anxiety and depression
The key point is that this is not only about what people eat or how much they exercise. It is also about when biological processes are taking place.
Even without shift work, a late and irregular routine can create similar patterns on a smaller scale.
Your Gut, Hormones and Inflammation Follow a Rhythm Too
Circadian rhythm influences far more than sleep.
Digestive function, bowel habits, hormone release and inflammatory processes all follow daily timing patterns.
When routines are inconsistent, this can contribute to:
Irregular digestion
Bloating or discomfort
Poor recovery
Increased inflammation
This becomes particularly relevant if you are managing joint pain, osteoarthritis or bone health concerns, where recovery and inflammation control are important.
What you can do to realign your rhythm
The goal is not perfection. It is consistency and gradual adjustment.
Start with a few key anchors in your day.
Morning routine
Wake at the same time every day, including weekends
Get outside within 30 to 60 minutes of waking
Aim for 10 to 20 minutes of natural light exposure
Eat your first meal within 1 to 2 hours and include protein
Morning light is one of the strongest signals for resetting your body clock. It sets up your sleep timing for later that evening.
Daytime habits
Keep meals at regular times each day
Front load your food intake so earlier meals are larger
Include daily movement, ideally outdoors
Use caffeine earlier in the day and avoid it in the afternoon
Consistency during the day supports stable energy and appetite regulation.
Evening routine
Aim to finish eating 2 to 3 hours before bed
Reduce overhead lighting and switch to softer, warmer light
Limit screen exposure in the last 60 to 90 minutes
Consider blue light blocking glasses in the evening
Create a wind down routine that signals the end of the day
Phones and streaming platforms are designed to keep attention. Putting physical distance between you and your phone in the evening can make a significant difference.
Sleep timing
Bring your bedtime earlier gradually by 15 to 30 minutes
Avoid sudden large changes
Focus more on a consistent wake time than forcing sleep
Sleep timing will adjust naturally when your morning and evening signals are aligned.
The Bigger Picture
This is not about strict rules or removing everything enjoyable from your routine.
It is about recognising that your body is designed to work in a predictable rhythm.
When light, food, movement and sleep are aligned, many systems start to regulate more effectively:
Energy becomes more stable
Sleep improves
Appetite is easier to manage
Digestion becomes more consistent
Recovery and inflammation improve
Small shifts in timing can have a wide impact because they influence multiple systems at once.
Want support putting this into practice?
Knowing what to do and implementing it consistently are very different things, especially when you are tired, busy, overwhelmed, or dealing with complex symptoms.
In my programmes, we work together to get you in to a routine your body can work with, that can then stabilise blood sugar, support healthy weight loss, restore energy, gut and metabolic health and support mood.
Everything is tailored to you, your health history, your symptoms, and your goals.
This newsletter is general guidance. If you want a personalised, root-cause approach tailored to your symptoms, health history, and goals, you can learn more about my Functional Medicine programmes here:
If you simply want a Functional Medicine overview of your current health and priorities, including a comprehensive blood test, I also offer a one-off Wellness Check consultation.
Small changes, applied consistently and appropriately for your body, can have far-reaching effects.
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