Using light therapy – when, for how long, and how?

As the days grow shorter and the autumn and winter weather turns gloomier, we get less and less natural light. Many people feel more tired at this time of year, find it harder to get going in the morning, or notice changes in their mood and sleep-wake rhythm.

Light plays an important role in regulating our body’s internal clock. Getting sufficiently bright light at the right time can help align our biological daily rhythm. Light therapy harnesses this effect: it uses a special light source to replace some of the natural morning light that is scarce in our surroundings.

But how should you use a light therapy lamp? How bright should the light be, when should you turn it on, and what should you look for when choosing one?

What is light therapy?

Light therapy involves using a light source designed for this purpose, with an appropriate brightness, for a set period of time, typically in the morning. Light entering through the eyes affects biological processes involved in regulating the circadian rhythm—that is, the body’s internal daily cycle of approximately 24 hours.

The best-known use of light therapy lamps is to treat seasonal affective disorder (SAD), or depressive symptoms associated with the winter months. In some cases, light therapy may also be considered for other problems related to the daily rhythm, but it is not the right solution for every instance of fatigue or low mood.

It is important to note that a light therapy lamp is not simply a bright desk lamp. When using one, the brightness, distance from the lamp, timing, and duration of use all matter.

How bright should a light therapy lamp be?

You will often see the figure 10,000 lux mentioned for light therapy devices. This is a commonly used reference level for light therapy, which many devices provide at a specified distance.

Lux measures how much light falls on a given surface. It is therefore not the same as lumens, which indicate the total amount of light emitted by a light source.

In practice, this means that the 10,000 lux figure shown on a lamp’s packaging is not enough information on its own. You should also check the distance at which this level can be achieved. If the stated brightness is only achieved from a few centimeters away, the lamp may be less convenient for everyday use.

When should you use it?

Light therapy is often used in the morning, as the right timing can help align the body’s daily rhythm with the transition between day and night.

Morning light can act as a signal to the body that the day has begun. However, its effect depends on when you use it, your own sleep-wake rhythm, and the problem you hope to address.

In general, morning use is a common starting point, but the exact timing is not the same for everyone. If your goal is to treat a diagnosed sleep or mood disorder, consult a professional about the right time to use it.

How long should each session last?

A commonly recommended duration for light therapy devices is 20–30 minutes a day at 10,000 lux. However, this is not a universal rule: the required duration depends on the actual brightness, the distance from the device, the manufacturer’s instructions, and individual circumstances.

Lower light levels may require longer sessions, but you should not increase the duration on your own by guesswork. Follow the manufacturer’s recommendations, and if you are using the lamp as a treatment, ask for personalized guidance.

In general, light therapy does not require you to look directly into the light source continuously. Position the lamp as directed, at the appropriate distance, so that the light reaches your eyes while you comfortably read, eat breakfast, or go about your morning routine.

What should you look for when choosing a light therapy lamp?

1. Adequate brightness at the actual usage distance

Don’t just look at the lux rating on the packaging. Check the distance at which the device provides the stated illumination, and whether you can comfortably maintain that distance during your morning routine.

2. UV-free light

When choosing a lamp for light therapy, it is important to ensure that UV radiation is filtered out. Look for a device specifically designed for light therapy, whose manufacturer clearly provides information about UV protection.

3. Ease of use

The lamp’s size and positioning matter, as does how easily it fits into your morning routine. A device that is easy to use is easier to use consistently.

4. Choose the right light for the right purpose

A light therapy lamp and everyday lighting serve different purposes. A light therapy device can provide high levels of illumination at a specified distance, while the purpose of home lighting is to create comfortable and appropriate lighting conditions for work, reading, and other everyday activities.

Light therapy and everyday daytime lighting—what’s the difference?

The two approaches can complement each other, but neither replaces the other.

A light therapy lamp is used for a specific duration and at a specified distance. In contrast, good-quality daytime lighting improves the lighting conditions in your home or workplace and can make everyday activities more comfortable.

During the day, spend time in natural daylight if you can—for example, go for a walk or work near a bright window. If that isn’t possible, suitable artificial lighting can help make your surroundings functional and pleasant.

However, an ordinary LED bulb does not automatically become a light therapy device just because it is powerful. The brightness, the amount of light reaching the eyes, the timing, and the design of the device all matter.

When should you seek professional advice?

Light therapy is not equally suitable for everyone. Consult a doctor before using it if you have an eye condition, take medication that may increase light sensitivity, or have bipolar disorder. If you experience headaches, eye strain, nausea, unusual restlessness, or sleep problems while using it, stop and seek advice.

If you experience persistent fatigue, significant changes in mood, or recurring sleep problems, it is worth investigating the underlying causes rather than relying solely on light therapy.

Find the right light for you

Using light mindfully does not have to mean following a complicated routine. Seeking out natural daylight, improving your morning lighting, and reducing evening light can all help make light better suited to the rhythm of your day.

At Say Hello Sun, you can explore a selection of light sources for different purposes. Discover light therapy solutions and choose one that suits your needs and intended use.

This article provides general information and is not a substitute for medical advice or the instructions provided by the manufacturer of a light therapy device.