The Danes are reportedly the happiest people in Europe, yet Denmark is the second country behind Iceland in terms of anti-depressant consumption.

Suicide incidence is much higher in countries that experience less hours of daylight and many people experience some form of Seasonal Affective Disorder (SAD), which manifests as symptoms of depression or low energy during certain times of the year, but especially in winter.

What is the explanation for all of this?

Studies have demonstrated that changing light levels throughout the day affects mood regulation, hormone secretion and can disrupt our circadian rhythm if there’s too much light at the wrong times.

Some people adapt to different levels of light better than others.

The circadian rhythm is our 24-hour cycle body clock

It’s governed by cortisol and melatonin release. Cortisol is our stress hormone and melatonin is a key hormone and super antioxidant made in the pineal gland and derived from serotonin, one of our most important neurotransmitters.

Serotonin governs a number of functions

This includes our mood, appetite and sleeping patterns. Our circadian rhythm tells us when we should be waking up or winding down for bed.

Our circadian rhythm also regulates many other of the body’s physiological processes so any disruption has a profound impact on our bodies and brains as melatonin secretion is disrupted and cortisol activity is increased.

Melatonin production is inhibited by daylight and occurs during dark hours

It plays a role in sleep, mood and immune and reproductive system activity. When melatonin levels are reduced, people may experience sleep disruption and mood swings.

light therapy_2Bright light therapy is used as a standard treatment for Seasonal Affective Disorder (SAD)

Bright light is a way to increase serotonin levels naturally without the need for pharmaceutical intervention, demonstrating a positive interaction between bright light and serotonin levels.

Perceived levels of happiness have a been shown to positively correlate with increased serotonin production while sadness negatively correlates with serotonin synthesis in the brain.

Light intensity levels

On the other hand, light intensity could have an impact on the intensity of emotions, with high intensity light making positive emotions more heightened, but also making negative emotions worse.

This could mean that reducing light intensity may make us less emotional in daily life.

Why are so many people suffering mood disorders?

One of my hypotheses (apart from my obvious favourite contributors of gut health and adequate vitamin D levels) is that that before we all had sedentary jobs in airless offices lit with artificial lighting, we (and by we I mean our ancestors) worked outside and lived in sync with natural rhythms of sunlight and darkness.

What can we do about it?

Light therapy: there are special lamps designed to alleviate SAD which are well-priced, readily available and proven to be very effective.

Increase our exposure to natural light: get outside, even in winter, open the curtains and let as much light in as possible, simple adjustments to the lighting in your house or office can have a huge effect. Get up earlier and try and synchronise as much as possible with daylight hours.

Exercise during the day: helps to increase melatonin levels.

An adjunct: Montmorency cherry juice, which contains natural melatonin taken at night to help improve melatonin levels as melatonin cannot be purchased in the united kingdom.

Foods and herbs which stimulate melatonin production: these include St John’s Wort and high tryptophan foods such as bananas, fish, beef, legumes, oats, peanuts, pumpkin seeds soy and sesame seeds.

Connect with Expert Carolina Brooks

WatchFit Experts change lives!

And they can do the same for you.


Pollyanna Hale Health and Lifestyle coaches
Lost 13 Kg in Total
Mel, 32y Location: London, United Kingdom Working with Pollyanna changed everything. I lost 13kg, got toned and have more energy than ever! Get same results!


Chriz Zaremba Fitness Consultant
Lost 45 Kg in Total
Chris, 50y Location: London, United Kingdom Lost 45kg after the age of 50 and now competes and wins physique competitions and runs marathons Check our weight loss plans