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Have you noticed the days getting longer? You may have found yourself face to face with the sun when you open the curtains in the morning, and that it’s no longer dark and gloomy when you leave your work at night. As summer approaches, the daylight hours are beginning to stretch out…

Most of us would admit to feeling healthier and more energised as winter fades into the distance. What role does light play in our well-being? How does it affect our bones and our brains?

Our circadian rhythm will continue without external cues (scientists who stayed in a cave with no natural light or time pieces found their circadian rhythm still followed a rough 24-hour pattern) but our body is also very responsive to light.

Light is an important signal that helps to kick start an enormous array of biological functions in the body.

One of the biological functions that light helps to kick start in our bodies is sleep. Light lets our brains know that the systems that promote wakefulness are in charge. Equally, when it starts to get dark our body begins to release melatonin, the chemical that helps us to sleep.

Some airlines are now using the cabin lighting on their planes to help combat jet lag. They are introducing bright light for boarding, relaxed lighting during dinner, and lighting that replicates a sunset to help passengers drift off to sleep.

Light can help us tackle insomnia

We now know that the type of blue light emitted from our tablets and phones can prevent us from releasing the necessary sleep hormones that help us to nod off.

New guidance from the UK Chief Medical Officers states that we should be having a technology free period before bed, and that gadgets should be left outside the bedroom.

A daily dose of natural daylight isn’t just important for our sleep patterns. Light triggers changes in the brain that make us feel happier. When the body recognises sunlight, which reaches the brain via the optic nerve, levels of the feel-good chemical serotonin increase. Adversely, those whose levels of sunlight are restricted – like shift workers – may find they struggle with depression.

There is one mental health condition that directly relates to daylight hours becoming shorter in the autumn and winter months: Seasonal Affective Disorder or SAD. Sufferers of SAD will find depressive symptoms emerging as the days shorten (and thankfully waning as spring approaches). The current hypothesis is that SAD is an effect of our circadian rhythm becoming desynchronised – directly caused by the decrease in sunlight.

If you suffer from SAD you should consider getting your hands on a SAD lamp – a bright light that mimics daylight. Half an hour’s exposure in the morning can help to shift your circadian rhythm and improve your mood.

We need vitamin D in order for our bodies to absorb calcium and phosphate from our diet – minerals that are crucial for healthy bones, teeth and muscles. Conversely, a vitamin D deficiency can lead to soft and weak bones, and skeletal deformities.

As luck would have it, we can get almost all the vitamin D we need from the sun – which is why it’s also knows as the 'sunshine vitamin'. Miraculously, our body creates vitamin D when direct sunlight hits our skin and so most of us are able to get all the vitamin D we need this way. Off course, too much sun can be dangerous! Take care to wear sunscreen and avoid direct sunlight during the hottest part of the day.