Mental Health

Light therapy: how do SAD lamps work to relieve symptoms of seasonal affective disorder?

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Lauren Geall
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Light therapy lamps are often held up as the answer to seasonal affective disorder (SAD). But how do they work? And what do you need to know before you invest in one? We asked an expert to explain all.

With autumn now in full swing and the evenings growing darker by the day, it’s understandable if you’re starting to deal with the effects of seasonal affective disorder (SAD).

Also known as winter depression, it’s a condition thought to be caused by reduced exposure to sunlight during the autumn and winter months, which leaves sufferers experiencing symptoms including low mood, a loss of pleasure or interest in everyday activities, and a need to sleep for longer than normal. And while some people will experience only mild symptoms – and find that activities such as getting outside regularly and exercising frequently will help to relieve most of their issues – for some, overcoming SAD can prove a lot trickier.  

In these cases, a range of interventions are often recommended, including talking therapy and antidepressants. But there’s another increasingly popular method of dealing with SAD which has risen to prominence over the last couple of years – light therapy.

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Backed by the NHS, light therapy involves the use of a light box – also known as a SAD lamp – to simulate exposure to natural sunlight. The only problem? SAD lamps can be a slightly pricey investment – so you’ll want to make sure they’re right for you before diving straight in.

To find out more about SAD lamps and how light therapy works, we spoke to Fatmata Kamara, specialist mental health advisor at Bupa UK. Here’s what she had to say.

How do SAD or light therapy lamps work? 

A woman looking out a rainy window
Seasonal affective disorder is thought to be caused by a decrease in sunlight exposure in autumn and winter.

While the exact cause of SAD is not fully understood, the main theory experts have come up with is that a lack of sunlight exposure can cause a part of the brain called the hypothalamus to stop working properly, which in turn affects the production of key hormones such as melatonin (which regulates sleep) and serotonin (which regulates mood).

It can also affect the body’s circadian rhythm (aka the body clock), which helps you to wake up in the morning and feel sleepy at night time.

In turn, the light exposure simulated by the SAD lamp can help to regulate the hypothalamus. “A SAD lamp works by replacing the light you’d normally see in the summer and helps to stimulate your brain to release feel-good hormones,” Kamara explains. “The light from a SAD lamp comes from a specially made device which gives off much brighter light than a normal light bulb.” 

Do SAD or light therapy lamps actually relieve SAD?

While some people experience benefits from using a SAD or light therapy lamp, it’s important to note that professionals aren’t sure how well it actually works, and the National Institute for Health and Care Excellence (NICE) say it’s not clear whether it’s effective.

“Evidence around light therapy is still not 100% conclusive, but it does look as though it can deliver positive short-term effects,” Kamara explains. “This means it could be a helpful way to banish the winter blues until the days start getting longer.” 

In this way, while there’s no definite answer as to whether SAD or light therapy lamps can offer everyone the same benefits, that doesn’t mean it isn’t worth it – it’s just up to you to decide whether you think light therapy could be effective for you. 

How to use a SAD or light therapy lamp

A woman eating breakfast with a SAD lamp next to her
You should aim to practise light therapy within an hour of waking up in the morning.

If you decide to give light therapy a go, there are some dos and do nots to follow. “Doctors recommend using light therapy at an intensity of 10,000 lux (the measure of how bright the light is) for 30 minutes every day,” Kamara explains.

“It’s best to use your lightbox within an hour of waking up in the morning if possible,” she adds. “You should also try not to use your lightbox after 5pm because you may find it hard to get to sleep afterwards.”

While you can do other activities while using your light therapy lamp, such as eating or reading, you’ll need to keep your body facing the light, Kamara says.  

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“To get the benefit, you must be awake with your eyes open. It can be difficult to keep up with your light therapy every day, but you may find your symptoms come back if you stop. You should keep using light therapy until the time of year when your symptoms usually go away on their own.”

It’s worth noting that light therapy isn’t recommended if you have some eye conditions or take medicines that make your skin sensitive to sunlight – if you think this might be you, make sure to read the patient information that comes with your SAD or light therapy lamp and ask your GP/optician to confirm it’s OK for you to use one. 

How long does a SAD or light therapy lamp take to work?

If light therapy works for you, it shouldn’t take too long until you start to see results. “You may notice your symptoms improve within a week or two, but sometimes it can take up to six weeks to work,” Kamara says.  

What conditions can SAD or light therapy lamps help with? 

A woman looking out the window in autumn
SAD lamps don't just help with seasonal affective disorder.

Seasonal affective disorder isn’t the only condition light therapy can benefit. “A SAD lamp can help with different mental health conditions, including seasonal affective disorder and types of depression that don’t occur seasonally,” Kamara explains.

“A SAD lamp can also alleviate symptoms of jet lag, sleep disorders and adjusting to a change in routine (for example, adjusting to a night-time work schedule).”

Are there any side effects to using a SAD or light therapy lamp?

You shouldn’t experience any serious side effects from using a SAD or light therapy lamp. “Any side effects from SAD lamps are usually mild,” Kamara says. “You might get headaches, blurred vision or nausea (feeling sick). It may also make you feel tired and irritable.” 

What makes a good SAD or light therapy lamp?

When you’re shopping for a SAD or light therapy lamp, there are a number of things you should consider besides how it looks. “Choose one that is made for treating SAD, comes from a reputable seller and meets medical guidelines,” Kamara recommends.  

“Your lightbox should come with instructions on how to use it, including how close to the box you need to be. You should also look for a lamp with a light surface area of around 12 by 15 inches – the larger the surface area, the higher the lux. Smaller lamps aren’t as effective and may need to be used more often for longer sessions.” 

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Kamara continues: “Before purchasing your SAD lamp, check that it filters out UV light and is labelled UV-free, because UV-light can damage your eyes and skin. You should also make sure that the lamp generates 10,000 lux of cool-white fluorescent light.”

Examples of brands that sell good SAD lamps include Lumie, who also sell the much-loved wake-up alarm clock, Philips and Beurer

If you think you might have SAD and have been struggling to cope, you should consider seeing a GP. They’ll be able to advise what to do next and refer you if you require further treatment. You can read more about SAD on the NHS website

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Lauren Geall

As Stylist’s digital writer, Lauren Geall writes on topics including mental health, wellbeing and women’s issues. She’s also a big fan of houseplants and likes to dabble in film and TV from time-to-time. You can find her on Twitter at @laurenjanegeall.