More light!

21. December 2023

The 22nd December is the shortest day of the year, on which the sun sets after a mere eight hours. The days may start getting longer after the winter solstice, but they remain quite short enough for the rest of the winter months. This has a strongly negative impact on many people’s mood. So, where do the winter blues come from, and what can be done about them?


For the vast majority of living beings, light is the stuff of life. This is why the God of the Old Testament begins his work of creation with light. So, it’s no wonder that the absence of light in the winter is very difficult for many people. The period from the start of November to the end of February in Germany offers the paltry total of just 160 hours of sunshine on average. The figure in the summer months is almost five times as much. The consequence is that ten to 15 percent of Germans are estimated to suffer from seasonal depression – the winter blues. They feel sad, tired, devoid of energy and unmotivated for no obvious reason. But whereas people with typical depression suffer from disturbed sleep and a lack of appetite, winter depressives tend to be subject to cravings for carbohydrates and sweets. They also sleep too much, and the quality of that sleep is not necessarily good.


Why is this? Daylight sets the rhythm of our sleeping and waking. Morning sunlight wakes us up and gets us going for the day. Light breaks down the sleep hormone known as melatonin and stimulates the release of the neurotransmitter serotonin.  In the dark months, in contrast, our body produces less of this feelgood hormone, and the sleep hormone melatonin is only slowly broken down in the course of the day. A chronic lack of light can even make us physically ill and susceptible, for example, to metabolic conditions or some types of cancer.


Get outside to recharge

The best thing to counter a lack of light is light! Which is why we should get as much of it as we can in the winter. Anyone who spends a good hour or so outside on a daily basis will generally get enough light, even in the winter. If you can, you should cycle to work – well wrapped up, of course, and provided that the cycle paths are not icy. If you take the train or the bus, you could try getting out one station early. If you drive, you could park further away from your workplace to get your fill of light and air.

Exercise is a reliably good way of lifting your mood. It boost serotonin production, gets your circulation moving and strengthens your immune system. A morning jog or weekend walk is therefore a good way of countering the winter blues.

Lux between summer and winter

Lux is the physical unit which is used to measure the intensity of illumination from a light source. On a clear summer’s day, we will be exposed to up to 100,000 lux. On a cloudy winter’s day, we will still get between 3,500 and 6,000 lux when we’re outside. Standard office lighting, on the other hand, offers barely 500 lux, and domestic lighting tends to give us even less. But if you work indoors all day or find it hard to get going on those dark winter mornings, you can however compensate for the lack of light with special daylight lamps. Here are a few tips:


Take a light shower in the morning

To benefit from light therapy, you should, if possible, spend some time in the morning sitting about one metre away from your daylight lamp. With lamps with an illuminance of 10,000 lux, half an hour is enough. If your lamp is less powerful, you will need to sit for longer – the instructions will tell you how far away from the lamp in question you should sit and for how long. While taking your light shower, feel free to have your breakfast, read, make a phone call or work. You don’t need to look directly into the lamp but should definitely keep your eyes open so that the light gets through to your retinas.


Restore balance to your sleep-wake rhythm

Lamps with an illuminance of around 10,000 lux and regular morning light therapy can help restore balance to a disrupted sleep-wake rhythm. Any excessive need for sleep will be reduced. You will be able to sleep for less long without feeling tired during the day. For this reason, it’s also not a good idea to use the lamp in the afternoon or evening. This will tell the body that it’s still broad daylight out there. Melatonin production will decrease, and you will find yourself getting to sleep too late.

How to find the right daylight lamp

If it is going to be effective against the winter blues, a lamp must offer an illuminance of at least 2,500 lux and 5,600 Kelvin. Kelvin is the unit used to measure the light’s colour temperature. The higher the Kelvin value, the higher the white and blue proportion of the light. This blue proportion is especially high in noonday light, and this is exactly the kind of light that daylight lamps are supposed to simulate. If you looking to buy a lamp, you should only select a model with a “certified medical device” label: in other words, a class II medical device as laid down in Directive 93/42/EEC for medical devices. This certification shows that the devices have been tested to ensure that they do not emit any harmful UV or infrared light.


Are daylight lamps bad for the eyes?

Daylight lamps certified as medical devices are fitted with UV filters and are therefore not deemed harmful to the eyes in the first instance. However, if you are suffering from an eye or retinal condition, you should first check with an optician whether you will be up to undergoing daylight therapy. The same applies if you are taking drugs which make your skin light-sensitive: for instance, particular antibiotics, anti-inflammatory drugs or high doses of St. John’s wort compounds.