Resetting our daily rhythms for better living

There’s something about summer that makes us slow down. The heat encourages us to savour life. The longer days invite us outside. And nature, in full abundant bloom, reminds us that it’s okay to pause and simply enjoy a sense of being very present in the moment. I’ve been loving the summer sunshine lately. It feels like a well-earned gift. We’ve made it halfway through the year. And summer offers us a moment to rest and luxuriate in that fullness. Recently, I was back on campus at Surrey University attending a fascinating lecture by Dr Daan Van der Veen, Senior Lecturer in Sleep and Chronobiology, titled Healthy Timing: Resetting Our Daily Rhythms for Better Living. It was all about how light and timing, especially daylight and meal timing, affect our sleep, metabolism, mental health and overall wellbeing.

One of the core takeaways from the lecture was that our modern lifestyles are out of sync with our biology.

We evolved to live in natural environments - waking with the sun, moving through daylight, and resting with the dark. But today, most of us live and work indoors. We spend our days under artificial light and our nights exposed to blue light from screens. This is a big deal, because light is one of the most powerful signals that tells our bodies what time it is - not just on the clock, but biologically.

According to Dr Van der Veen and the research team at Surrey’s Chronobiology department, getting enough daylight during the day, and avoiding light exposure at night, is essential for our circadian rhythms - the internal clocks that govern our sleep-wake cycles, hormone production, mood, metabolism and more. We’re getting blue light where we shouldn’t  and not enough natural light when we need it.

What are Circadian Rhythms?

The word circadian comes from the Latin circa diem, meaning “about a day.” These rhythms run on roughly 24-hour cycles (actually, 24.2 hours), and they influence nearly every system in the body. We have a master clock in the brain (the suprachiasmatic nucleus or SCN), which is directly responsive to light. And we also have peripheral clocks in organs and tissues around the body, which are influenced by other cues like food, temperature, movement and social interaction.

When these clocks are out of sync - perhaps when we eat at night, stay up scrolling, or work night shifts – we can become more prone to fatigue, mood issues, poor performance, and even serious health problems.

Shift workers, for example, face significantly higher risks of:

Obesity

Type 2 diabetes

Cardiovascular disease

Depression

Certain types of cancer

It’s not just about getting “enough” sleep. It’s about when we sleep, eat and get light exposure.

What happens when our internal clock is out of sync?

Dr Van der Veen shared the story of the famous Bunker Experiment by Professor Jürgen Aschoff, which began in the 1960s. Volunteers lived underground in a WWII bunker without natural light or time cues. At first, the door was left open so participants could sync with day and night. Then it was closed. Visitors avoided giving away the time.

Over 45 days, the participants gradually drifted out of sync. After 25 days, they thought it was one day earlier than it actually was. This demonstrated the body’s internal clock - and how, without natural light cues, it starts to lag.

We all have a chronotype - our own individual sleep-wake preference. Some of us are morning types (larks), others are evening types (owls), and many fall in between. This is largely biological and shifts across the lifespan - for example, teenagers and young adults tend to be more owl-like, while we naturally shift earlier as we age.

There’s no one-size-fits-all approach, but understanding your body’s natural rhythm helps you live more in tune with it.

What can we actually do?

Dr Van der Veen presented research from Surrey University involving blue-enriched light supplementation in older adults. This simple intervention involved using 17,000k cool-toned light during the day leading to measurable improvements in:

Sleep regularity

Daytime activity

Mood and wellbeing

Earlier sleep times

Reduced anxiety

In short, it helped people feel better - without any drugs, just by getting the right light at the right time.

We also learned that:

Morning light improves sleep quality and reduces sleep fragmentation

Evening light (especially blue light from screens) delays sleep and lowers sleep efficiency

Most people don’t get nearly enough daylight exposure. Since the 1800s, our shift to indoor, sedentary lifestyles - combined with urban architecture - means we spend most of our time under dim, artificial light, especially as we age (the eye’s lens yellows and pupils shrink, reducing light intake).

New note book and pen at the ready to take copious notes from Dr Daan Van der Veen,

What will help maintain the right circadian rhythm for us?

Here are a few simple ways to support your circadian rhythms:

Start the day with sunlight

Get outside early. Open the curtains wide. Let your brain know it’s time to be awake.

Eat your meals at regular times

Your digestive system is tuned to the clock too. Try not to eat too late at night.

Limit screens in the evening

The blue light from your phone or laptop tricks your brain into thinking it’s still daytime.

Consider light therapy if you're indoors all day

Especially in winter or if you’re older, blue-enriched daytime lighting can support mood and energy.

Know your chronotype and honour it

Larks and owls both have value. Find a routine that supports your rhythm.

Screen time and social media

Social media and stimulation can delay sleep. Sleep hygiene means setting boundaries and reducing mental load.

Get outside

We evolved to live under the sky . So nothing beats getting outside in our natural habitat. More on how how bodies align with sunlight and produce Vitamin D

Discover why Vitamin D why it matters for your health all year round and how to get enough.

Read my latest article: Vitamin D: Are you getting enough sunshine?