A significant number of the American workforce are actually shift workers. They don't keep a conventional schedule of going to work at 9:00 AM and stopping at 5:00 PM. As our societies become more 24-7, we have more shift workers. So the swing shift or working just nights, certainly the medical profession, we've been doing this for a long time, but now it's in retail stores everywhere across America. There's always something awake and therefore somebody's gotta be manning their job. It's a problem for some people. Since 80% of us have a conventional schedule, it's hard to shift that the advantage of working nights is that the pay differential tends to be a lot better. And it tends to be that night owls are attracted to those shifts, but there's not enough of them to actually make that up. So what happens is that we're fighting our biology. It's normal to want to sleep for most of us in the dark and normal to be more alert during the day. So even if somebody has to work the night, they have a hard time falling asleep during the day. So typically they're very sleep deprived and some people really have a problem called shift work disorder. And what happens is that all the biological functions that are driven by the circadian rhythm, that 24 hour cycle, which affects our hormones, our immune system can get disrupted. So actually, especially in women, fertility and menstrual cycles are very obviously disturbed.