Fifteen percent of the American workforce are shift workers, and there are at least 600,000 of them in the New York City metropolitan area alone. They show up to work in the late afternoon or very early morning, and, not surprisingly, many of them are not getting enough sleep. But sleep deprivation and the off-hours are more than just a nuisance — shift work can be a major health threat.

Sleep deprivation, especially for shift workers, can increase your risk for obesity, hypertension, heart disease, cardiovascular disease, diabetes, even cancer. The World Health Organization has added shift work to the list of probable carcinogens. And in a 24-hour economy where the number of shift work jobs are on the rise, researchers are trying to understand why this work can be so harmful and what might help.

Dr. David Blask, a biologist at the Tulane University School of Medicine, is trying to figure out why shift workers have a higher risk of developing cancer. His lab has shown that the problem may have to do with light at night and the hormone we produce in darkness: melatonin. Blask says,  “Melatonin actually has direct anti-cancer effects, in other words, it can directly inhibit the growth of breast cancer cells." He says, "We will lose that cancer protection by being exposed to light at night and this is particularly troublesome we think for people who work night shifts.” But shift workers have to work at night and they need light to do their jobs.

Which is why Mariana Figueiro, associate professor at the Lighting Research Center at the Rensselaer Polytechnic Institute, is looking at whether different colors of lights can be a solution. Her research shows that while blue light keeps you alert, it also suppresses melatonin. But red light keeps you alert without suppressing melatonin. “We think that the red light has the potential to be the best of both worlds. It will not suppress melatonin, and it will give you that alerting effect that you can get say, with a cup of coffee, “ she says.

Figueiro imagines that shift workers could use red light goggles, red light boxes, or red lights around their computer monitors to “dose yourself at certain times of night. So I think break rooms would be an ideal place. You could have light boxes, they have blue light boxes for treating seasonal depression, you could have red light boxes.”

Red light does not solve all of the health issues related to sleep deprivation and shift work. But by allowing shift workers to stay alert without suppressing melatonin, red light could keep workers awake and still let them produce that hormone we know has direct anti-cancer effects.

This story is part of WNYC's Clock Your Sleep Project.