Conquering those winter blues

According to an overview of SAD in the journal Psychiatry,¹⁷ “Light therapy is established as the best available treatment for SAD.” Indeed, light therapy alone has been found to be more effective than the antidepressant Prozac.¹⁸ Even placebo was more effective than the drug — a finding that highlights the fact that drugs are not the answer for this condition.

Interestingly, while daylight as a whole is beneficial to fight off the winter blues, blue light has been found to be particularly beneficial. According to one 2010 study,¹⁹ blue light appears to play a key role in your brain’s ability to process emotions, and its results suggest that spending more time in blue-enriched light could help prevent SAD.

It may be even more effective than the bright white light typically used in light boxes to treat SAD and other forms of depression. In a previous interview, researcher Dan Pardi explains the peculiar effect blue light has on your brain, which sheds further light on why it’s so important to expose yourself to blue light during daytime hours, and why you need to avoid it at night:

“[R]ods and cones in the eye … are specialized cells that can transduce a photo signal into a nerve signal … In the mid-90s, a different type of cell was discovered … [called] intrinsically photosensitive Retinal Ganglion Cells (ipRGC).

It does the same thing as rods and cones: It transduced light to a nerve signal. But instead of the signal going to your visual cortex, it goes to your master clock. Those cells are most responsive to blue light.

If you can block blue light, you can actually create something called circadian darkness or virtual darkness. What that means is that you can see, but your brain doesn’t think that it’s daytime; your brain thinks that it’s in darkness.

That is actually a practical solution for living with artificial light in our modern world … With more awareness, future digital devices will adjust lighting in the evening to automatically dim and emit amber/red light [instead of blue]. This is much better for healthy circadian rhythms and sleep quality.”

Blue light is prevalent in outdoor light, so your body absorbs the most during the summer and much less in the winter. Because of this, the researchers suggested that adding blue light to indoor lighting, as opposed to the standard yellow lights typically used, may help boost mood and productivity year-round, and especially during the winter.

Timing and Intensity of Light Exposure

If you know that SAD symptoms tend to come back for you every winter, you may want to start light therapy in late summer. Keep in mind, however, that blue light at night should be avoided as it will inhibit melatonin production and impair sleep.

So, to be clear, you only want to expose yourself to blue light in the morning, and possibly afternoon, but not in the evening. Findings differ on the issue of the most effective timing, but at least one meta-analysis²⁰ found the largest mean effect size among those exposed to bright light in the morning and evening.

To be on the safe side, I’d suggest avoiding light therapy once the sun begins to set, to avoid further disruption of your circadian rhythm. The light intensity is also important. Outdoor light is in the neighborhood of 10,000 lux, and this is the level of intensity you’re looking for.²¹

This is about 100 times stronger than a normal light bulb, so to be effective, you’ll need to get a special light box, and make sure it generates at least 10,000 lux and emits white and blue light, not yellow or infrared. As noted by the authors of a 2015 paper addressing the assessment and treatment of SAD:²²

“In the Scandinavian countries, light rooms, where light is indirect and evenly distributed, are available. Typically, light boxes filter out ultraviolet rays and require 20 to 60 minutes of exposure to 10,000 lux of cool-white fluorescent light daily during fall and winter.”

Additional Treatment Strategies for SAD

In addition to optimizing your vitamin D and getting daily light therapy, the following strategies may also be helpful in the treatment of SAD:

While there are individual differences, as a general rule, aim for eight hours of sleep per night. If you struggle with insomnia or poor quality sleep, review the many suggestions listed in “Sleep — Why You Need It and 50 Ways to Improve It.”

Refined sugar and processed fructose are known to have a very detrimental impact on your brain function and mental health in general. A classic book on this subject, “The Sugar Blues” by William Dufty, delves into this topic in great detail. Cutting out artificial sweeteners will also eliminate your chances of suffering their toxic effects.

Interestingly, vegetarians are four times more likely to suffer from SAD than nonvegetarians, so a primarily plant-based diet may not be ideal during the winter season. Vegetarians are also twice as likely to suffer from nonseasonal depression,²⁷ which suggests nutrient deficiencies may be involved in both.

In closing, it may be worth noting that it’s natural for your body to want to slow down somewhat in the wintertime. While this can be difficult when your work and personal life dictate otherwise, allowing yourself to slow down a bit and surrender to the overwinter process³² may ultimately help you to respect your body’s circadian rhythm and recharge.

That said, this doesn’t mean you should plant yourself on the couch for the winter and not venture outdoors. On the contrary, staying active and spending time outdoors during the day are among the best “cures” for SAD.