SAD lights – fluorescent tubes to fight depression

Ask most people if they prefer a sunny day to a cloudy one, and you’ll doubtless get a silly answer! We may not always realize it but the Sun is our feel good source, and for quite a few of us the winter months, which feature less and less sunlight, provides a real challenge to the way we feel. That’s where an SAD light can help. SAD lights brings the benefits of the Sun indoors and helps fight off the blues for many people who knowingly or not are SAD sufferers.

What is SAD?

Seasonal Affective Disorder (SAD) is a form of depression commonly associated with lack of exposure to sunlight during winter months. Symptoms include low mood and profound lack of motivation. Tiredness and a constant desire to sleep are also indicators. Such symptoms always warrant the attention of a GP, as they can be difficult to surmount alone.

Physical causes

Lack of sunlight adversely affects production of melatonin and serotonin hormones in the body, causing SAD. This imbalance can be helped naturally by a SAD lamp and other remedies.

Melatonin helps to regulate the body’s circadian rhythm (body clock) and produce sleep. Sufferers of SAD often have higher than average amounts of melatonin in their body during winter months.

Serotonin is a neurotransmitter affecting multiple human functions, including sleep, appetite, mood, and nerve cell communication. Lack of exposure to bright, natural light decreases the body’s production of serotonin, and low serotonin levels are commonly linked to depression.

The role of light in SAD

One of the chief treatments for SAD is bright light therapy. This involves the patient being exposed to an intense artificial light of remarkably high quality, resembling daylight as closely as possible. Most UV radiation is removed from the light source, to avoid damage to either skin or eyes.

Treatment times vary not only between patients, but also according to the intensity of light. A 2,000 to 10,000 lux light is typically used, which is many times stronger than any regular bulb. Thirty minutes to three hours of treatment per day is normal.

If circumstances permit, regular walks and plenty of exposure to natural daylight are prescribed for most sufferers of depression. SAD is often caused when work prevents this possibility (it is common in night-workers, who generally sleep through winter daylight).

A supporting role – daylight is not enough!

As a preventive measure or to support ongoing SAD treatment, products such as SAD tubes or SAD lights are available. These closely match daylight in most respects, except for sheer intensity.

To deal with a misconception, for a bulb to actually behave like daylight, it is not enough for it to emit a 6500K daylight colour temperature. Although this is a useful quality, it has to be combined with exceptional colour rendering. A near-maximum 98% Colour Rendering Index (CRI) score always indicates this.

This combination of critical colour rendering and a daylight colour temperature is very rare in electric lighting. Incandescent is arguably the best light source for colour with a default CRI 100 score, but the filament of a lamp would melt before it resembled daylight in overall colour.

At the high end of the LED market, products with outstanding colour rendering are emerging, but they’re expensive and meant for other purposes. For health applications, a fluorescent SAD tube offers an easy, affordable answer to improving indoor light quality.

Fluorescent SAD tubes

Lyco stock a choice of three different Sylvania SAD Activa 172 Fluorescent Tubes, in 18 watt, 36 watt, and 58 watt versions.

From a health perspective, the most important point about these tubes is their ‘full spectrum light’, as Sylvania and other manufacturers call it. But what is this?

In marketing, ‘full spectrum light’ refers to a light source that emulates daylight in its colour-rendering ability and colour temperature. Other daylight or sunlight qualities might be implied, especially UV radiation in a fluorescent tube. This is useful for producing vitamin D in the body, which affects the normal functioning of the nervous system.

Sylvania SAD Activa tubes meet all of these criteria. They radiate at all wavelengths of the visible spectrum (i.e. all visible colours exist in their light), with an overall 6500K colour temperature. They also radiate outside of the visible spectrum to produce a safe amount of UV light.

When a light source covers the entire visible spectrum, it scores a very high or maximum CRI rating by default. It’s a property that trumps the Colour Rendering Index. The Sylvania SAD Fluorescent Tubes have a CRI 98 score, which signifies outstanding colour rendering.

How will these lights help fight SAD?

With SAD tubes installed, everything falling under their light will look natural, as if being lit by neutral window light. Colours will be enlivened and rendered accurately. The tubes will reduce eyestrain, headaches, and tiredness, and they’ll stimulate energy.

Light intensity and quality affects serotonin and melatonin levels in the body. This is the basis for bright light therapy and exposing SAD sufferers to as much good-quality light as possible.

Installing SAD tubes

The energy-efficient Sylvania SAD Fluorescent Tubes come in a standard T8 size, which is a 1” diameter tube with a double-ended G13 cap. They will slot into any existing T8 linear fluorescent light fitting. A long average lifespan of 14,000 hours adds to their exceptional value.

To take a look at our full range of SAD lights.

For more inspiration, advice and ideas take a look at our Lighting Advice section.


Andrew Evangelidis Head of Buying

Andrew is an experienced buying professional who takes an entrepreneurial approach to identify new lighting solutions and ensure Lyco have first-to-market ranges for our customers. Having previously worked for well known brands such as Wickes, Carphone Warehouse and Toys R Us, Andrew has now turned his hand to sourcing commercial lighting and ensure our customers receive top brand quality products at marketing leading prices. He manages a team of commercial and decorative buyers who travel the world finding new products that our customers don’t even know they need yet.