What You Need To Know About Seasonal Affective Disorder (SAD) Lights

If it's wintertime, and you're living a long way from the equator - in places such as Finland or Canada or the South Island of New Zealand - you're not exposed to much sun light.

This lack of sunlight impacts our health, wellbeing and mood. So much so that their is a disorder associated with those who suffer from lack of sunlight.

It's called Seasonal Affective Disorder or SAD.

This seasonal dip is often referred to as "winter blues", as people lacking sunlight having higher levels of depression, lowered immunity and decreased health and wellness.

Fortunately, technology can be utilised to help overcome SAD. This lighting technology aims to mimic the suns rays - allowing you to effectively supplement your daily sunlight with some artificial light.

These lights are commonly referred to as 'SAD Lights'. In this article I'm going to break down everything you need to know about these lights including:

  • Why they're so important
  • How they improve your health, sleep quality and mood
  • Why popular (and expensive) SAD lights are not effective (and why they may be doing more harm)
  • What you need to look for when buying SAD lights
  • A low cost SAD light setup 
  • And finally, when to use SAD lights for optimal results.


The Importance of Sunlight for Health

The light spectrum humans have lived under on the earth, consists of a range of frequencies  emitted by the sun. To be exact, that light spectrum is made up of ultraviolet (UV) light, visible light, and infrared (IR) light:


The Sun's light spectrum. Note: the UVC that is emitted by the sun, does not reach the earth's surface)
Source – Optimalhealthpartner


As covered in great detail in my article How Technology and Blue Light Are Ruining Sleep and Making You Sick, Fat and Tired - light plays a vital role in our day to day health and wellbeing.

Light exposure impacts our mood, our sleep, our hormones and much more.

Blue light for instance can help wake us up, or ruin our sleep.

Red light is healing and therapeutic assisting growth and repair.

Infrared light heats us and can help with detoxification.

UV-B light is used for vitamin D synthesis in our skin.

These are just a few examples to show you how light exposure is so important.

This is why those of us who cannot get adequate sunlight exposure (wherever it's due to our climate or perhaps our daily environment - stuck in doors covered up all day can bring about the same SAD effects as someone who lives close to the pole in winter time) can suffer health consequences. 

And if this is the case, then you need to look at using technology to supplement these precious sunlight rays that you are missing out on.



Types of Light Needed to Mimic The Sun

SAD lights are used to help stimulate the bodies natural circadian rhythm. Soaking the body in the light that it is deprived of.

But as we covered above, not all light is the same. Spending 8 hours a day under a fluorescent light bulb next to a computer screen is not the same as being exposed to the bright, full spectrum light from the sun.


For the best health and performance outcomes our SAD light should provide us with all key elements that the sun emits.

Let’s have a look at these lighting conditions. This picture displays how the light emittance pattern – or the light spectrum – of sunlight develops throughout the day:


How sunlight progresses during the day
Source – Jack Kruse Forum

The day starts with visible light (VIS) and infrared (IR). Visible light consists in all the colors of the rainbow, which are violet, blue, green, yellow, orange and red. But in the morning the colour temperature in the visible light range is warmer - meaning there is more reds and oranges than there is blues and greens (note - this is why I use my Red Light Panel in the morning)

Infrared also consists of different sub-types, but these sub-types are not that important for the current article. To keep things simple, I will just discuss infrared as a whole.

As you can see in the picture above, ultraviolet A (UVA) only emerges later in the morning. And if the sun moves really high up in the sky - as it does at the equator, or in summer - then ultraviolet B (UVB) is added to the mixture (note - hence why many people are deficient in vitamin D in winter - as there are no UVB rays).

If you’re living close to the north pole in a place like Norway, you don’t get UVB during from early fall to early spring at all. And you may not get much, if any, UVA during the darkest months of wintertime either. This lack of UVB (and sometimes UVA) during the fall and wintertime is common for all places that have a high latitude.

To check UVB ray exposure in your location, I highly recommend downloading the app called 'DMinder'.


Latitude Map
Source - Skyandtelescope.com

The Optimal SAD Light Spectrum

As mentioned earlier, to get the most out of your SAD lights, they should do two things emit the same wavelengths of light that the equatorial sun emits.

We can also take this one step further - the SAD light should follow the light pattern as it rises and falls in the equatorial (or summer) sky. 

Following this lighting pattern is important. Remember that different wavelengths of light at different times of the day affect our body in various ways.

When you follow the light spectrum of the sun that is displayed in the sun’s pattern listed above, you’ll ideally want your SAD light to:

  1. Emit mostly visible light and infrared during the morning and evening hours.
  2. Next, you’ll want to add some UVA and UVB around noon, when the sun is high up the sky.
  3. And after sunset, SAD lights - and blue light in particular -  should not be used at all.

By mimicking the sunlight with your SAD light, you will maximise the benefits of your SAD light, while minimising the negative effects that SAD has on the body. 

Remember though - natural is always best. 

You should therefore never see SAD lights as a replacement for your daily sunlight requirements. Instead, SAD lights should be seen as just one tool that can you can move your health towards the right direction.

The Perfect SAD Light For Our Circadian Rhythm

Knowing what type of light our SAD device should emit, and when it should be emitted, we can now work towards finding the perfect SAD light for our body.

The perfect SAD light should contain infrared light and visible light during the morning and evening, and has some added UV during the hours around noon.

By using that light spectrum through our SAD light, we attempt to mimic the sun's light spectrum.

To achieve high levels of infrared and visible light, a halogen floodlight is recommended:

Halogen floodlight

Source - Amazon.com

The halogen bulb emits a large amount of visible and infrared light. The light output of these halogen floodlights is amazing.

Make sure you do not buy an LED floodlight, as LED floodlights often emit a lot of blue light without emitting any infrared. Getting a halogen version is therefore necessary.

You can see here the high levels of red light into infrared light that a Halogen bulb emits.

You can buy a 400W or 500W halogen floodlight for as little as $10, and a 1000W floodlight for $25 online.

Why Infrared Light? We Can't Even See It?!

What are the benefits to the infrared light that is emitted by the halogen bulb? I will not go into full detail regarding red and infrared light, because in previous articles I’ve talked about near infrared, infrared light saunas and red light therapy. These  therapies use the wavelengths that are also included in halogen lighting. 

The benefits of red light & near infrared light – include:

  • reducing pain and stiffness [8],[9]
  • improving wound and injury healing
  • reducing inflammation levels (which lies at the basis of many modern diseases) [10],[11]
  • enhancing the collagen formation in your skin [12]
  • decreasing wrinkles and skin roughness [13]
  • improve recovery after exercise [14]
  • increase your steroid hormone levels [15]
  • stimulate thyroid functioning [16]. A healthy functioning thyroid is essential for achieving fat loss. [17],[18

However, if you are serious about reaping the health benefits of light, I highly recommend reading THIS article and investing in a dedicated red light therapy device such as the MitoRed Light.

Next to infrared and red light, halogen bulbs contain other forms of visible light, such as orange, yellow, green, and some blue light.

This full spectrum visible light - that contains all the colors of the rainbow - has several benefits:

  1. Full spectrum light improves your mood and fights depression, and makes you less prone to develop other mood disorders.[19],[20]
  2. Full spectrum light also boosts cognitive performance,[21] by heightening dopamine and serotonin levels in the brain.[22],[23]

You’ll feel a lot better when using a halogen SAD light if you can't get outdoors during the day.

Additionally, full spectrum visible light enhances your insulin sensitivity, meaning that food that you eat is less likely to be stored as bodyfat.[24]

You could say that a SAD light will even help you lose fat and increase your gym performance! (Again though, you could just get outside in the natural sunlight!)

How To Use Your Halogen SAD Light

To use the halogen lamp, let it shine into your eyes and body from a distance.

If you heat up when exposing yourself to the halogen's light, then you're sitting too close.

Place the halogen light somewhat further away from your body, until the light no longer overheats you.

You want about 20-30minutes of light exposure. 

You can simply use the halogen SAD light when reading the newspaper, or when working on your computer.

Though the best time to use the halogen floodlight is in the morning - aligning with the suns higher levels of red and IR light. 

The UV Light Bonus: Blacklights or Reptile Bulbs

The Halogen lamp covers the essentials when it comes to SAD lights. But we can improve our setup one step further: by adding some UV light to simulate the sun's UV rays.

Remember that the sun emits UVA and UVB when it is highest in the sky.

While excessive UV light can be damaging, the right amount of UV light is very beneficial, and even necessary for achieving optimal health. Sunlight that contains UVB, for example, is necessary for creating vitamin D through the skin.[25] Without sunlight, you cannot create the right form of vitamin D in your body.

But UV light has many more benefits than creating vitamin D. UV light:

  • improves relaxation,
  • makes you happier
  • and even makes more emotionally balanced.[26]
  • UV light also increases your dopamine levels, which leads to more motivation and greater confidence in life,
  • and boosts your mood.[27],[28]

Even pain sensations are decreased with UV light.[29] UV light stimulates the release of endorphins, which is the same substance that makes you get that “runner’s high”.[30] The endorphins also explain why sunlight (and blacklights that emit UV rays) make you feel so good, while LED lighting - void of UV -  does not.

Maybe this is why you feel so good after a day at the beach?! 

Overall, your optimal SAD lighting setup should aim to contain some UV light exposure around the middle of the day.

The best ways to add UV light to your setup is to use a blacklight, or a reptile bulb.


Blacklight Bulb
Source – Squarespace

You can buy mercury vapor blacklights here. When buying a blacklight, it’s important to buy one that emits UV light at a 365nm wavelength. Most blacklights have a product description telling you at which wavelength they project their light.

It’s currently not possible to perfectly simulate the entire UV part of the sun’s light spectrum by using light bulbs. Blacklights generally do not contain UVB, for example. (If you want a unit that produces quality UV-B rays, check out the Sperti Vitamin D box.

Blacklights have some drawbacks for generating UV light, as the bulbs themselves contain mercury. As this mercury is contained within the bulb, it’s only dangerous if it gets out should a bulb break.

If a blacklight ever breaks, make sure you follow the cleanup procedure – which prevents spreading too much of the toxic mercury through your house.

Fluorescent blacklights are another option to adding UV light to your indoor setup:


Fluorescent Blacklight
Source – Amazon


However, fluorescent blacklights (and LED blacklights) have the disadvantage that they flicker many times per second. Flickering means that the bulb emits light in pulses tens or hundreds of times per seconds, but does not emit any light between these pulses.

Studies have shown that the flickering of fluorescent of LED lighting is irritating to humans. This is true for all fluorescent lighting, and not just fluorescent blacklights.

Nevertheless, I do recommend that you add just one blacklight to your halogen SAD light around noon. Combining the halogen floodlight with a blacklight will give you all the benefits of IR, visible, and UV light. 

Reptile Bulbs For UV Exposure?

Reptile bulbs are another option to upgrade your SAD light setup with UV . An example of a reptile bulb is the Exo Terra Solar Glo:


Exo Terra Solar Glo

The Solar Glo is a mercury vapor bulb as well. The Solar Glo can be bought in either 80W, 125W or 160W, and needs a special lamp holder. When you search for this bulb on the internet, you should be able to get the bulb and a lamp holder for about $75, anywhere in the world.

The Solar Glo can be used as a standalone SAD light, but should not be used during the early morning, as it contains high levels of UV light. 

If you need to get the most out of your SAD lights, use the halogen floodlight in the morning, and the Solar Glo during the afternoon. By using these bulbs at these times, you'll mimic the sun as closely as possible.

Solar Glo Light Output

These reptile bulbs also create vitamin D in the skin. They are a great tool to get vitamin D in the fall and wintertime, for places that do not get any UVB during that period.

One blacklight or one reptile bulb supplies more than enough UV to get your needs met. You don’t need multiple of these bulbs to get most of the UV benefits. The goal of the indoor UV lighting is not to achieve the sun’s full intensity—instead, we only want to add a little bit of UV light to our SAD lighting setup, while getting most of our UV exposure by going outdoors.

The reason for wanting to use the blacklight or reptile bulbs, is because a small amount of UV already gives you enormous health and performance benefits. In other words, adding one small blacklight to a room will already give you the relaxation, cognitive performance, and motivation benefits of UV light.

Why Store-Bought SAD Lights Are Inadequate

I hope you now know what bulbs you need for an optimal SAD light setup, and when to use them.

But what about these commercial SAD lights sold in the electronic stores?

Avoid them.

All store bought SAD lights that I currently know of, only emit visible light. These lights thus miss the entire infrared part of the light spectrum.

Additionally, a lot of these SAD lights emit large quantities of blue light as well, making these lights much less useful.

Blue light in high doses is very damaging to the body and cellular health. Combine this with the fact that we're already saturated in blue light (as explained HERE) and you can see why these SAD lights are no good for us.

These store bought SAD lights therefore do not follow the light spectrum that the sum emits in her daily cycles. Here are some examples of store bought SAD lights:


NatureBright SunTouch SAD light

Source - Amazon.com


Philips GoLITE BLU

Source - Amazon.com

Some of these SAD lights even exclusively emit blue light, making them terrible choices for your long-term health. 

Furthermore, these store bought SAD lights are also much more expensive than the halogen floodlight option. Traditional SAD lights cost anywhere between $50 and $150, while halogen floodlight's will only set you back $10-$25.

And if that wasn't enough reasons to skip the mainstream SAD Lights - here's one final reason.

These SAD lights do not achieve a very high light intensity. They're simply not very bright. And light intensity is important.

The halogen floodlight for example, does achieve a very high lighting intensity. Without wanting to go into the exact calculations of the lighting intensities, you can expect the 500W or 1000W halogen to be significantly brighter than these SAD lights.

What About SAD Light Gadgets?

You might also have some questions about some new biohacking gadgets have been coming out that attempt to simulate the SAD lights. The HumanCharger that I reviewed HERE is a good example:

Valkee Human Charger

The HumanCharger contains two earplugs that emit light. The light emitted by the earplugs, reaches the human brain, telling your body that it's time to be/stay awake.

I go into great detail and review the published literature on this device in the article - HumanCharger Review: Does Light In The Ear Help With Sleep, Jet Lag & SAD?

In a nutshell - The HumanCharger is effective for treating SAD, and for travel and jet lag. I personally use my device every morning.

However it should be mentioned that it's not a complete solution if you a looking to create an artificial sun as it doesn't emit any IR or UV light.

In A Nutshell - The Best SAD Light Solution

To create your own SAD light setup, combine a halogen floodlight with a UV bulb. The UV bulb - such as a blacklight or reptile bulb - should only be used during noon. 

And SAD lights should never be used after sunset, because they will ruin your sleep quality. 

This SAD light setup described in this article - which combines a halogen floodlight with a UV bulb - is truly full-spectrum, because it contains infrared, visible light, and UV light.

Because of its full light spectrum, this SAD light setup has much broader benefits for your mood, energy levels, and even body composition than the traditional SAD lights that you can buy in the store.

I hope this guide has answered a few questions you may have had around light and Seasonal Affective Disorder. Also, I hope it saves you a few dollars!

If you have any questions, please leave them below.


Items Mentioned:

This is a post by Bart Wolbers. Bart finished degrees in Physical Therapy (B), Philosophy (BA and MA), Philosophy of Science and Technology (MS - Cum Laude), and Clinical Health Science (MS), and is currently a health consultant at Alexfergus.com. 


[+] References

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