Light therapy is a commonly recommended treatment option for seasonal affective disorder (SAD). It involves using a device that replicates natural light at a specific intensity.
When choosing a light therapy device, you may encounter the terms “full spectrum light” and “broad spectrum.” They refer to the types of light produced by a light box or SAD lamp. Both work differently, which we’ll discuss today to help you choose the right option for managing SAD during the chilly and gloomy winter months.
Comparing Full Spectrum vs. Broad Spectrum Light
| Full Spectrum Light | Broad Spectrum Light |
| Replicates natural sunlight yet produces harmful UV rays | Simulates natural sunlight without emitting UV light |
| Casts a purple or bluish glow | Broad-spectrum light therapy devices use fluorescent bulbs with a pure white or whitish glow. |
| Most full-spectrum lamps use low-cost diffuser screens to filter UV light. | Broad-spectrum lamps offer complete eye and skin protection from UV rays. |
| A full-spectrum light therapy device’s color temperature is rated at 5,500 Kelvin and above. As a result, it can be glaring to the eyes. | A broad-spectrum light therapy device’s color temperature is rated at 3,000 to 4,000 Kelvin, producing no glare. |
Find medical-grade, research-backed light therapy boxes on the Alaska Northern Lights website.
Table of Contents
- What is a Full Spectrum Light?
- What is a Broad Spectrum Light?
- How Does Light Therapy Work?
- How Much Light Should You Get From a Light Box?
- How Effective is Light Therapy?
- Choosing a Light Therapy Device: More Factors to Consider
- Style
- Size
- Weight
- Additional Features
- How to Use a Light Therapy Lamp
- Frequently Asked Questions
- Conclusion
What is a Full Spectrum Light?
Full-spectrum light bulbs are made to try to imitate natural sunlight, but they emit harmful ultraviolet (UV) rays and often produce a purple or bluish cast. These bulbs may include:
- A complete visible light spectrum, including invisible infrared and ultraviolet light.
- A balanced visible light spectrum only.
Companies selling full-spectrum light therapy devices now block UV rays through diffuser screens. However, they use low-cost plastic shields that can cause reddened, puffy, and burnt skin. Full-spectrum light boxes with this level of protection may even make the eyes photosensitive, particularly if you use them while taking various medications.
Finally, full-spectrum lamps emit light with extreme color temperatures at 5,500 Kelvin and above, which can be harsh on the eyes.
Learn more about the disadvantages of full-spectrum light on our blog.
What is a Broad Spectrum Light?
Broad spectrum light boxes offer lighting that’s as close as you can get to full spectrum without the UV rays. The bulbs used for these devices emit a pure white light, although some broad-spectrum light therapy boxes and lamps may produce a slightly whitish glow.
Some light box manufacturers use broad-spectrum light bulbs to protect patients from the danger of UV rays. Our light boxes, including the North Star 10,000, don’t produce UV light.
For color temperature, broad-spectrum lamps of 3,000 to 4,000 Kelvin produce less glare and can help you manage symptoms of SAD. The Center for Environmental Therapeutics (CET) recommends using UV-filtered broad-spectrum light therapy devices rated at 4,000 Kelvin. Or, if you’re advised to limit light exposure to prevent macular degeneration, choose lamps with a color temperature of 3,000 Kelvin.
How Does Light Therapy Work?
Whenever you use a broad-spectrum lamp for bright light therapy, it helps stimulate some of the body’s important functions.
One of the benefits associated with broad-spectrum light lies in how it affects the circadian rhythm. If this internal clock makes sleeping and waking up challenging for you, getting broad-spectrum light in the morning may reset it. In turn, you can sleep better and see a significant energy boost.
Broad-spectrum light therapy also initiates photobiomodulation, wherein light stimulates cellular function to produce more energy, decrease inflammation, and speed up wound healing. Plus, it can tell your brain to raise low levels of neurotransmitters such as serotonin (the “happy hormone”). The more serotonin the brain produces, the happier you feel on sunny days. It also makes broad-spectrum light therapy an effective mood booster.
How Effective is Bright Light Therapy?
According to older research, this type of therapy has worked for 50 to 80% of patients with SAD. You may see reduced symptoms several days after starting light therapy, but consistent treatment throughout the winter months can reduce the risk of relapse.
How Much Light Should You Get From a Light Box?
Research has shown that light intensity is key to success with light therapy. UV rays are considered dangerous to the eyes and skin, so it’s best to buy a light box or SAD lamp that blocks more than 99% of UV light. This protection helps prevent eye and skin damage when you use a light box.
More importantly, bright light therapy devices should give you 10,000 lux of light while you sit at a comfortable distance. It’s similar to being outside on a bright sunny day and produces 66 to 100 times more light than standard indoor lighting. The broad-spectrum North Star 10,000 provides 10,000 lux of light at two feet, making it effective, easy, and safe to use!
Choosing a Light Therapy Device: More Factors to Consider
Along with the type and amount of light, you should consider the following when choosing a light therapy box or lamp.
Style
Light therapy devices come in different styles, from table lamps to other designs. Think about your preferred time and place to undergo treatment and the amount of space your room has to find the right design.
Size
Ideally, you’d want a light box or lamp that’s around 200 square inches wide. More compact devices are easy to use and carry; however, moving your head a little can draw your eyes away from them, so you may need to move these units much closer to you.
Despite this disadvantage, small light therapy boxes or lamps can be placed on packed shelves or nightstands. Bigger lamps can illuminate larger rooms or spaces.
Weight
You should also consider weight when choosing a bright light therapy lamp. Taking lightweight devices with you is much more convenient than carrying bulky units. It’s best to keep a hefty light box or SAD lamp in one place.
Additional Features
Some light therapy devices have adjustable settings. For example, you can increase or decrease a light box’s brightness to your preferred amount. Other units work without adjustable settings, making them easy to use.
How to Use a Light Therapy Lamp
Before using a light therapy device, find a table or counter and put the unit on the surface to ensure you sit comfortably. Also, check the manufacturer’s recommended distance, as it’s another crucial factor for effective therapy.
Using 10,000-lux light boxes or SAD lamps requires you to sit 16” to 24” away from them. Otherwise, you’ll need more time to get enough light to manage your symptoms.
Besides placement and distance, you should pay attention to how the light shines on you. Indirect illumination may be less effective or lengthen your exposure time. Make sure your eyes slightly face the lamp, which should be tilted at 15 degrees if it casts light downward.
Conversely, light therapy devices illuminating a space should cast light down into the top of your eyes, like natural sunlight.
Frequently Asked Questions
Are light therapy lamps safe?
Light therapy lamps are safe and effective. However, they’re not FDA-regulated for SAD treatment.
If you need a light therapy device, the CET has set specific requirements for effective treatment. Your chosen lamp should meet these criteria.
Additionally, you may experience some side effects while using light boxes. Stop treatment if they occur.
When to do light therapy?
Light therapy is best done early in the morning for 20 to 30 minutes daily. Consider using a light box during the fall and winter months so your body has enough time for hormone production.
You can also do bright light therapy if you work at night or struggle with shift work sleep disorder.
Who should not use light therapy?
Patients diagnosed with any of the following medical conditions shouldn’t use light therapy.
- Retinal-related conditions such as diabetes and macular degeneration
- Systemic lupus erythematosus
You should also avoid light therapy if you take photosensitive medication or are diagnosed with bipolar disorder.
Is full-spectrum light good for the eyes?
While full-spectrum light can promote good health as it mimics natural sunlight, full-spectrum light therapy devices produce harmful UV rays and significant glare, which can be harmful to the eyes.
Broad-spectrum light therapy devices are a better option, offering effective UV light protection and less intense light than full-spectrum lamps.
When can I stop light therapy?
Generally, you can stop light therapy in the spring and summer when your symptoms have subsided. But if you’ve just started treatment and you experience side effects such as mild headaches or eyestrain, postponing it is necessary.
Conclusion
Full and broad spectrum lights are made to help you boost your mood and energy levels in the cold, gloomy winter. However, we recommend using broad-spectrum light therapy boxes or lamps, as they replicate natural sunlight without emitting UV rays.
Visit the Alaska Northern Lights blog today for more about bright light therapy.