We haven’t even reached the end of October, but those long, heady days of summer feel like they belong to another lifetime. The clocks have gone back, the drizzle is frizzing out hair and we’re bracing ourselves for the gloom that’ll last until March at least.

For those who suffer with Seasonal Affective Disorder (or SAD), the winter months are even more difficult.

Seasonal Affective Disorder is a type of low mood that comes and goes in a seasonal pattern, according to the NHS website. SAD is sometimes known as ‘winter depression’ because the symptoms are usually more apparent and more severe during the cold months.

How does natural light affect our body?

‘The light-dark cycle is the most important part of our biological process,’ says sleep expert, Dr Guy Meadows, host of the Insomnia Recovery Podcast.

‘Light exposure helps regulate our circadian rhythm, or body clock. Cells in our eyes detect the presence of “blue” light (the colour in the visible light spectrum that can be seen by human eyes). When the sunlight hits our eyes, it regulates every biological process, telling our body whether to be active or inactive.’

According to Dr Meadows, the arrival of light tells our gut to wake up and release appetite hormones; when the light disappears, this tells our gut to go to sleep. Light also activates serotonin, the hormone responsible for boosting our mood, sleep and sex drive. ‘Darkness affects our body like an office closing at night,’ he says. ‘The problem is that at this time of year, this natural biological process is interrupted.’

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How do we get more light into our lives?

Get outside at 8am

The most important way to boost your body clock. If you can get outside first thing. ‘Morning light is the very best booster of serotonin.’ says Dr Meadows. ‘Don’t wear sunglasses, because they will hide the melanopsin receptors in your eyes. For the same reason, make sure you walk into the light, rather than have it at your back.’

If you can’t get out first thing in the morning, a lunchtime walk is better than nothing.

Invest in a light box

‘If your routine doesn’t allow you to get outside in the morning, consider buying a light box,’ says Dr Meadows. Light boxes – devices that simulate natural sunlight – come in a variety of models and prices, but you don’t need to spend a fortune, just make sure they are 10,000 lux or more. For those who can afford it or are on the go all day, you can buy SAD light glasses which start from around £100.

Sit by a window

It makes a huge difference if you can sit by a window, says Dr Meadows. ‘There was a study that took a set of office workers and divided them into two groups. One group sat by the window, and the other sat away from the window. After a month, tests revealed that those who sat by the window had better sleep, improved focus and reduced food cravings, compared with those who sat only in artificial light.’

Cut back on carbs

Speaking of food cravings, those tea-time crumpets might taste yummy, but they’re a short-term gain. Dr Norman Rosenthal is an American psychiatrist and expert in SAD. ‘We crave carbohydrates becaue they have an energising effect, and we’ll naturally want to do anything to boost our energy,’ he says. ‘But overeating carbs leads to weight gain so that can become another reason to feel sluggish and low.’ Moderation is key.

Take your Vitamin D

First things first, we don’t ‘get’ Vitamin D from the sun in the same way that eating an orange gives us vitamin C. ‘Vitamin D is made when the sunlight hits a substance under your skin called 7-Dehydrocholesterol,’ says Susan Lanham-New, professor of human nutrition at the University of Surrey. ‘However, in the UK, the human body makes no vitamin D at all between the months of October and March, because the sun is too low.’

You can get small amounts of vitamin D from eating oily fish such as salmon or mackerel, but nowhere near enough. Everyone needs a supplement in the winter. The NHS recommends that adults and children over the age of 12 months take a daily supplement of 10 micrograms, also written as 400 IU.