As the seasons change, many individuals find themselves struggling with Seasonal Affective Disorder (SAD), a type of depression that typically occurs during the fall and winter months when daylight is scarce.

One highly effective treatment is bright light therapy. This involves exposure to artificial light that mimics natural sunlight, which can profoundly improve mood and energy levels. Let's explore the benefits of bright light therapy and how it can be used to combat seasonal depression!

What is Seasonal Depression or SAD?

Seasonal depression, often referred to as SAD, is characterized by symptoms similar to those of general depression. The lack of sunlight during these shorter days of the year disrupts our biological clocks, leading to depressive symptoms. 

What causes SAD, and what are the common symptoms? 

Without enough bright white light exposure to stimulate the hypothalamus, a part of the brain linked to our body's internal clock controlling the sleep-wake schedule, our body may increase its production of the sleep hormone melatonin while decreasing the production of serotonin, the feel-good brain chemical that helps regulate mood. Bright light therapy helps reset the internal clock, offering those suffering some relief from their symptoms. 

Common symptoms of SAD  

• Feeling depressed and hopeless
• Feeling low in energy, sluggish, and agitated
• Sleep disturbances
• Difficulty concentrating 

What is Bright Light Therapy?

Bright light therapy, also known as phototherapy, exposes individuals to a light box that emits a very bright light (usually 10,000 lux) for about 20-30 minutes each day, typically in the morning, to help reset the body's internal clock. 

As mentioned above, full spectrum light therapy uses specialized bright, artificial lighting to treat SAD or to provide a daily dose of sunshine for those who don't spend enough time outside in natural sunlight. 

What is Bright Light Therapy Used For?

The most common use of light therapy is to treat SAD, a type of seasonal depression during the fall and winter caused by a lack of sunshine and natural light. But you don't need to suffer from a clinical diagnosis of SAD to enjoy the stimulating benefits of bright light therapy: think of bright white light as a vitamin to be taken daily for optimal health and wellness! 

Bright Light Therapy for SAD

SAD (seasonal affective disorder), aka the winter blues, is characterized by feelings of depression that begin as soon as daylight hours diminish during the fall and winter. 

Light Therapy to set your circadian clock or for light deprivation 

As we mentioned above, bright light is a necessary "vitamin" for our body - you don't need to suffer from a clinical diagnosis of SAD to enjoy the stimulating benefits of bright light therapy! 

Just as in its use as therapy for SAD, light therapy can help prevent issues associated with lack of sunlight: without the presence of bright light early each day, our body has a difficult time waking up in the morning, staying alert throughout the day, and falling asleep at night. 

For those who are indoors when the sun is out, supplementing bright light through light therapy every morning that you aren't outside in the sun will benefit you greatly.

Light Therapy for Depression

We hope you see the trend here; light therapy helps regulate mood and energy and keeps our bodies running smoothly! 

Since bright light stimulates and helps regulate our hormones and neurotransmitters, it isn't surprising that studies suggest light therapy can be helpful for those suffering from bouts of depression—even if they are not seasonally related. Specifically, as mentioned before, bright light affects the up-regulation of serotonin, the neurotransmitter linked to mood/happiness and well-being.  

How does bright light therapy work? 

So we've spoken about its uses, but how exactly does full spectrum bright light therapy work?

The role of Blue Light 

What do we mean by blue light? It may be helpful to see a diagram of the electromagnetic spectrum and the visible light spectrum within it. Blue/Violet light is at the far end of the visible spectrum, right before ultraviolet (UV) light. 

As seen below, wavelengths get shorter and more energetic as we move up the spectrum. Midday sunlight is mainly comprised of the higher part of the visible light spectrum—blue light.  

10,000 lux: bright blue light

Blue light on its own may be full of energy, but to trigger a significant cascade of biological responses in our body, we need a lot of it. Think of it like this: the more you put in, the more you get out!

In terms of brightness, what exactly do we need? You undoubtedly have already seen the answer everywhere: 10,000 lux. Lux, pronounced (lucks), is a unit of illumination. The higher the lux, the brighter the light source. For reference, daylight on an overcast day around noon is around 1200 lux.  

Our eyes: a window to the soul and our master clock

Our eyes are constantly taking in information from the environment around us. Perhaps surprisingly, not only do eyes allow us to see, but they also reserve a part of their ability for non-visual tasks, such as determining how much light is in our environment! 

Our eyes detect light through specialized non-visual photopigments called melanopsin (a light-sensitive retinal protein). Melanopsin is most reactive to shortwave blue light, which, if activated by the presence of light, sends off a signal to our brain's hypothalamus. Within the hypothalamus lies a cluster of cells (called the suprachiasmatic nuclei, or SCN) whose job is to coordinate our daily cycles of behavior and physiology with our external environment. 

In other words, our circadian rhythm (master clock) runs internally but responds and adapts to our external world. The circadian rhythm runs in a cycle of approximately 24 hours, and apart from controlling our sleep/wake schedule, it controls other biological processes, such as the timing of hunger, digestion, body temperature, and the release of hormones to maintain energy throughout the day. 

How to choose the best bright light therapy for SAD

Now that we know more about the workings of light therapy, how does one choose a device to get their daily dose? Here are some criteria to help in your decision.

Lux: As mentioned before, your unit should provide at least 10,000 lux of light at a distance of ~ 2 feet to trigger any meaningful health response.  

Now, let's decide on the form: 

Light Pads

Available in different sizes, you might find light "pads" similar in appearance to a kindle or iPad, or you might find replaceable light "box" units where you switch out the bulbs.

Light Boxes

Lightboxes may be larger (most measure 2 feet in diameter), but their practicality lies in their lifespan: one box should last a lifetime - provided that you change out the light bulbs as needed! Changing out the bulbs is great, as it allows you to change bulbs as they begin to dim naturally over time. This next point is critical to us, as it will enable you to determine whether your light source is LED or fluorescent. 

LED vs. Fluorescent Light Therapy

The most common light technology used for light therapy these days is LED. 

And for many, LED doesn't sit well with their physiology. We wish we could send you on your way with incandescent or halogen light bulbs, but those options don't produce a blue enough light to serve as true light therapy (plus, light bulbs on their own may not be bright enough a light stimulus unless you were to use many bulbs). Full spectrum fluorescent light therapy will be your best bet. 

Can't I use full spectrum or daylight light bulbs for SAD? 

It won't hurt, but relying on light bulbs alone will leave you wanting more. A common misconception is that a full spectrum light bulb serves as light therapy on its own. We wish that were the case, but the dose of light needed to elicit a biological response in humans is bright - so bright that you wouldn't be able to use it as a general light source. Light therapy uses full spectrum lighting but includes other parts a light bulb on its own can't provide. We wrote an article that goes into more detail about whether you can use full spectrum light bulbs for SAD. We highly recommend reading it! The same goes for daylight bulbs - which, by the way, say nothing about a light's quality or fullness of spectrum. Daylight bulbs usually only refer to color temperature, about 5000-6500K. That might be the blue-white light we need for light therapy, but again, light bulbs won't cut it on their own. 

Of course, Full spectrum bulbs such as Chromalux® help so much with well-being and have many other awesome benefits (like nourishing infrared) over standard, general-use light bulbs. Use them in conjunction with your light therapy sessions! 

How to Use Bright Light Therapy 

Use your light therapy device in the morning

Light therapy is most effective when used in the morning. (You don't want a bright blue light to keep you wired through the evening)! 

Keep it on the kitchen counter or your work desk in the morning.

Place up to 2 feet away from you, to your side.

Your light therapy manufacturer can tell you exactly how close you should be to your device to get benefits, but a general guideline is about 2 feet. 

Let the light shine into open eyes, but don't look at it directly!

The most important thing is for light to reach your open eyes. If you work using blue light filtering glasses, you'll want to take those off while using light therapy for the most effective dose. 

How long should I use a light therapy lamp per day?

Try for 20 minutes at first to see how you respond; you should begin to feel alert. If you start feeling jittery, that's an indication to place your unit a little further away or use it for less time. You'll soon learn how your body best responds, and your needs may change over time!

Closing Thoughts

Well, that, in a nutshell, is bright light therapy. We hope you'll consider adding it if it's not part of your wellness toolkit!

And, if you're a seasoned user, we hope you were able to glean some helpful information from this article! Read on for some of our recommendations to nourish and support your well-being this fall/winter season...  

Full Spectrum Light Bulbs for SAD

We highly recommend using Chromalux® Full Spectrum Light Bulbs to help support your mood and well-being. Unlike other full spectrum bulbs available on the market these days, these use a unique glass technology to purify light in a way most reminiscent of natural sunlight: vivid colors, increased contrast, and that particular feeling of well-being one can only get from being in the sun. They also have nourishing infrared light, the spectrum of light sunlight provides, but most full spectrum LED bulbs do not. 

Consider using the above in places where you use light in close proximity, i.e., a bedside table lamp or a floor lamp by the couch. Light is like a vitamin: you want to make sure what you take in is high quality and valuable for your body. Make the light that's closest to you count!

Light Therapy Boxes for SAD

We start with our brightest and best medical-grade non-LED full-spectrum light therapy box, Aurora™ 10,000 Lux Full Spectrum Light Therapy Box. Aurora™ is the perfect desk or kitchen counter companion during the darker months (or throughout the year for Circadian support!) . While most light therapy lamps are throw-away, the Aurora™ light therapy box will be in your wellness toolkit for the rest of your life. All you'll need to do is change out the bulbs as needed! 

If you prefer something more portable, try the HappyMood Mini Light Therapy Pad. It offers portable light therapy with adjustable levels, and it is still highly effective!  

💡Thanks for reading!

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