During shift work, use as much light as safely possible when alertness is required and darkness for sleep.

“So if you're finishing out that 2:00 AM shift, that's when you would want to avoid bright light exposure, you'd want to go home, you'd really want to avoid watching TV if possible.”

“Ideally you want to view as much light as possible and as is safely possible when you need to be alert.”

“So even if you're sleeping in the middle of the day, because you have to work at night, if you wake up during that about of sleep, really try hard to limit the amount of light, which is going to be harder for shift workers, right? Because there are generally a lot more lights on and bright lights outside, so you would want to close the blinds and limit artificial light inside.”

“And for those of you that are doing shift work, what I can say is try and avoid getting bright light in your eyes in the middle of your sleep cycle.”

“So using light as a correlate of alertness and using darkness as a correlate of sleepiness, what this means is, see as much light as you safely can during the phase of your day when you want to be awake.”

“For instance, should you see light during your shift? Well, this is a matter of personal choice, but ideally, you want to view as much light as possible and as safely possible when you need to be alert. So that would mean from 4:00 PM to 2:00 AM. And then you would want to sleep. So using light as a correlate of alertness and using darkness as a correlate”