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  • Writer's pictureSophie Bostock, PhD

How to Fight Winter Fatigue

● Do you feel low in the winter months?

● Do you struggle to get motivated when it’s dark and cold outside?

● Do you rely on comfort food to make it through the day?

After the October clock change, as the days get shorter and it gets colder outside, at least 1 in 5 adults experience a triad of symptoms commonly known as the ‘Winter Blues’: lack of energy, low mood and over-eating.

The combination of not feeling energised, and eating more, can be a recipe for weight gain.

Some people also notice that they are more irritable, worry more, have difficulty concentrating, feel less sociable, or sleep less well in the winter months.

For as many as 1 in 20 people, seasonal depression is severe and returns every year; they may be diagnosed with Seasonal Affective Disorder, or SAD.

SAD is less common in countries around the equator, and generally more common above or below 30 degrees latitude. This is gives us a bit of a clue as to one of the key contributing factors..


Bright light plays a key role in regulating our circadian rhythms, the 24 hour patterns of activity and recovery which govern everything from appetite, mood, immune function and concentration to our sleep-wake cycle.

During the winter, we not only have fewer hours of daylight, but the sun appears lower on the horizon and so the sunlight we do get is less intense.

One theory behind the winter blues and SAD is that sufferers are sensitive to these lower light levels and their circadian rhythms in mood and alertness become disrupted. In the morning, the sleep hormone melatonin may linger for longer than normal, making them feel sleepy. Serotonin is another hormone involved in positive moods, appetite and alertness. Sunlight is one of the triggers for the production of serotonin, so low light levels could contribute to low serotonin levels.

If this is true, and lack of light plays a major role in SAD and the winter blues, then deliberate exposure to bright light should help...

And it does!

Light Therapy

Light therapy is the first line therapy for SAD, and improves symptoms in about 50 to 80 percent of those affected. Light can be delivered in several ways: lightboxes, light alarm clocks by the bed, or light-emitting caps or visors. For clinical SAD doctors, may prescribe medication alongside light therapy.

If you decide to try a light box, look for something with a CE mark, preferably which says it can deliver 10,000 lux. The typical treatment dose would be to sit 1-2 feet from your light box at the same time every morning for 30 minutes. Try to have the light box at eye level, but avoid looking directly into the light by positioning at a slight angle, perhaps 45 degrees to the right or left from your midline or eyes.

Light therapy has been shown to reduce daytime melatonin, increase serotonin and improve night time sleep.

If your winter blues are on the mild side and you don’t want to invest in a specialist light, you can use the same principles and just try and get some regular light exposure outside in the mornings, especially on those beautiful crisp and clear sunny days.


Sunlight has some impressive benefits over and above the effects on our circadian rhythms. Sunlight on the skin can not only stimulate the release of serotonin, but can also spark the release of feel-good beta-endorphins, and has antibiotic effects.

The Victorians called exposure to sunlight ‘heliotherapy’. One of the most impressive effects of sunlight was to cure rickets, a disease of bone deformities which became common for children growing up in cramped conditions in the dirt and smog of inner cities. Sunlight quickly became a recognised cure, but it wasn’t until the 1920s that Vitamin D was identified as the protecting factor.

Vitamin D keeps bones, teeth and muscles healthy by increasing the intestinal absorption of calcium and phosphorous. Ninety percent of our vitamin D is produced by the body in response to sunlight, with the remainder coming from the diet, mainly from oily fish, eggs, fortified soy milk, and shiitake mushrooms.

In the winter, the intensity of UVB radiation is too low for the body to produce its own vitamin D. Most of us can rely on vitamin D stored in the body to see us through the winter, but about 1 in 4 adults become deficient in vitamin D. Risk factors for vitamin D deficiency include increasing age, darker coloured skin​​, eating a vegan or vegetarian diet, a high BMI or just spending lots of time indoors.

There are vitamin D receptors all over the brain and body. Vitamin D deficiency has been linked to a raft of different health conditions including SAD and depression, fatigue, heart disease, respiratory infections, diabetes, cognitive impairment, chronic pain and osteoporosis.

Confusingly, vitamin D supplementation doesn’t seem to reduce the symptoms of SAD, so vitamin D deficiency might be a symptom rather than a cause, but it’s still worth knowing that the NHS recommends that adults take a daily vitamin D supplement of 10 micrograms in autumn and winter to protect bone health.

What else can you do to prevent SAD?

The fact that not everyone suffers from a winter depression goes to show that this is a multifactorial condition, which can be influenced by our biology (including our genes and general health), our environment (including exposure to sunlight), but also by our health behaviours, our social context and mindset.

Similar things will help to protect against seasonal depression, or the winter blues, that will improve emotional wellbeing at other times of year. For example:

● Eating a healthy Mediterranean style diet, rich in fruit, vegetables, nuts, legumes, oily fish and unprocessed foods - research shows that improving diet alone can improve mood. One of the symptoms of the winter blues is a tendency to overeat, so you could experiment with using smaller plates to encourage sensible portions, set yourself food goals and/or keep a food diary. Drinking plenty of water rather than caffeinated drinks could also improve your energy and sleep quality.

● Regular physical activity - in the winter this might mean investing in a gym membership or warm outdoor clothing to reduce the excuses not to go out! Sign up for a class or group with a friend as extra incentive to make the commitment.

● Spending time with friends - social contact can buffer the effects of stress and boost positive emotions. When we’re tired, we rarely feel like socialising, but once we make the effort, we rarely regret it.


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