I think I might be a bat. At least, that's how I feel looking out my window in the morning and seeing nothing but frigid, Minnesota winter darkness staring back at me. Like so many other workers in the United States, I'm always up well before the sun, usually typing away by 5:00 a.m. And as I wait for that first glimmer of glorious light on the horizon, the question is, what time should work actually start, not based on social expectations, but based on biological science?
The short answer is, probably about an hour and 45 minutes after sunrise, whenever that happens to be in the year and for your geographic location.
The reason has to do with the role of light in waking the body up. As human beings, we're naturally programmed to respond to get up with the sun and go to bed when it sets. More specifically, a protein in the retina, malanopsin, responds to blue light and tells the master clock in your hypothalamus it's time to get going. That triggers additional signals that suppress melatonin, a hormone that makes you sleepy, and increase cortisol, which for all its bad press, helps with alertness.
Now, the problem is, for much of the year, sunrise, which naturally gives us the blue light we need to start this process and wake up without an alarm, often happens later than the world says we need to be on our feet. The average start time in the United States is 7:55 a.m., although there's a range from 7:00 a.m. to 8:24 a.m. In the summer, the issue isn't so bad, because sunrise can happen as early as 5:30 a.m. You can take the 20 minutes or so you need for light to wake you up, spend an hour to shower, eat and dress, endure the typical 25 minutes to commute and easily get in by 7:55 a.m.
But in the winter, sunrise is pushed back as much as two hours. Right now, for example, where I am, sunrise is about 7:45 a.m., just 10 minutes before I "should" be at my desk to meet the standard start time. If I followed science and commuted like most people, though, the earliest I probably should clock in would be 9:15 a.m.
As another issue, this setup assumes you can just wake up and smoothly transition out the door. Many workers can't. Working parents, for instance, often need extra time to get their children to school or daycare. On mornings when my daughter has band, for instance, we both have to get up a half an hour earlier so I have time to drive her to class.
There are two ways to deal with this conundrum. The first is to allow for more flexible work schedule. Anna North discusses some of the studies that support this concept in her article for The New York Times. It's an idea growing in popularity, especially as the gig and global economy grows. This would also accommodate the fact that, while light influences our wake times, some people have internal clocks that are shifted forward or backward a bit (the famous night owls and early birds), and that other factors like age influence our rhythm. Some schools already are experimenting with later start times and getting good results.
The other option is to use technology to trick your brain. You can use a sunrise alarm for this. These devices simulate sunrise. They slowly increase the amount of light in your room, which gives your body the signal to tip your hormonal balance and wake up. They often still have a regular alarm that will sound if you happen to sleep through the light alarm for some reason. This can help you reset your internal clock to be in sync with everyone else, and it can help shift workers cope with the lack of a natural sunrise cue, too.
When it comes down to it, few of us probably are getting up when we should through the entire year. But as the evidence for the benefits of sleep as related to productivity, morale and other critical issues mounts, here in my dungeon, that sunrise alarm is looking pretty dang attractive. If a more flexible arrangement works in your business to accommodate a more natural but consistent schedule, consider it.