Blue light therapy might help fatigue

In an experiment conducted by researchers from Monash University and the Epworth Hospital, people who’d had a traumatic brain injury—such as from a traffic accident or a fall—saw improvement in their fatigue after being exposed to a session of blue light every morning.

In our most recent podcast, we asked neuropsychologist Dr Toby Cumming from the Florey Institute, who wasn’t involved in the study, what he thought of it.

“I think that was a fascinating study,” he said. “It did look like it had small effects on fatigue. So very early days for blue light therapy I think, but in terms of an easily available, cheap, no-side-effect therapy, I think it holds promise.”

This fits in with what we already know about how light affects our daily rhythms of sleeping and waking. We experience jet lag when the times of night and day are thrown out by flying overseas (or for some people, by daylight savings). And in recent years there’s been concern that looking at bright screens late at night can disrupt our sleep patterns.

It’s not just any light though; blue light in particular seems to be necessary. Special cells in the retina of our eyes contain a pigment called melanopsin that responds to the colour blue. When activated, these cells send a signal to the brain telling it to wake up.

For this study, published in the journal Neurorehabilitation and Neural Repair, the researchers tried to test the theory on a group of people with fatigue from a brain injury. They used a device called the Philips goLITE M2, which has a grid of 66 blue LEDs. Participants had to sit in front of it for 45 minutes every morning for four weeks (not continuously, just for a few seconds every few minutes).

The blue LEDs emit light with a wavelength of 465 nm, which is roughly this colour (generated using the Spectra program from www.efg2.com)

The people using this blue light box saw a drop in their fatigue of about one point on the seven-point, self-rated Fatigue Severity Scale. Two other groups, using a yellow light box and no light box, didn’t see any improvement.

What’s more, when the blue-light group were followed up two weeks after the experiment, their fatigue scores had nearly returned to what they were before. This fits with the theory that the blue light was responsible for their improvement.

This was only a small, limited experiment, so it’s too soon to say that blue light has been proven effective, or to assume that it will also work for stroke survivors. And it’s worth noting that the blue light didn’t eliminate the patients’ fatigue entirely, although they did feel it reduced it.

Blue light would also be expected to be fairly safe. Commercially available devices like those used in this experiment should comply with international safety standards. The only side effect reported in the experiment was that one of the ten participants had a headache on one day in the four weeks.*

If you think you’d like to try it yourself and don’t have access to a light box, you can use an iPad or other tablet. The screens of those have similar brightness to the Philips device, and there are blue light therapy apps you can buy.

Or, for an even cheaper option, you could just save the blue rectangle above onto your tablet and use that. It could be difficult to keep your attention for more than a few minutes though.

* One other patient had diarrhea, but the researchers concluded that probably wasn’t caused by the light box.