Basking under bright sun can help cure winter blues

Published on Sat 1 Mar 2008

BECKY RYNOR, Canwest News Service

You might think those white fluorescent lights washing over you all day long are plenty bright enough, or even too bright.

But new scientific studies indicate brighter light, not above you but vertical light directed at the eye and in a different colour spectrum could have positive benefits for Alzheimer's sufferers, people with depression and for anyone's overall good health, according to a leading researcher into the effects of light.

"We do have a free light source out there - it's called the sun," Jennifer Veitch told a meeting of lighting professionals in Ottawa.

"Maybe your Grade 2 teacher was right when she said go outside and play at recess. I think it's incredibly ironic that the people who get the most bright light exposure right now, that I know of, are people who smoke because they all go outside." She said the goal in modern-day lighting design is not to only increase lights in general, but "to give people opportunities to be exposed to higher light levels at specific times and specific places. So we don't need to be scared that this is going to throw away our efforts to be energy efficient." Veitch said most of the office light we are exposed to is white light, while the sun delivers a high light dose throughout the colour spectrum.

"It looks as though what is needed is a higher light dose in the blue-green light spectrum," Veitch said, although she cautions, "this does not mean people should be sitting in blue-green light all the time." "We are not talking about increasing light levels everywhere all the time. It appears that we may be able to get the benefit of higher light levels at specific places and specific times." Computer screens and TVs, for example.

"You have captive eyeballs at that point, the light source is mostly vertical and it may be a great way to actually deliver, for short focused times, that higher light dose." She said it could be energy efficient, "and it gives people something interesting to do." Alzheimer's patients, who often suffer from disrupted sleep patterns and night-time restlessness, "which is a big problem for caregivers," may also benefit from this research.

"It's likely the case that institutionalized Alzheimer's disease patients have very low light exposure, so the problem may not be entirely the disease," she said.

Veitch said some field research has shown exposure in the late afternoon or evening, to bright blue light as opposed to the dim red light more commonly used in nursing homes, improved night-time sleep for Alzheimer's patients.

Other research shows even increasing the level of regular room lighting during daytime hours improved the sleeping patterns of patients with dementia.

"The jury is still out," Veitch said. "We have some clues that we need to increase our light dose, but we're not clear in how much, or when or in what way."