Teens may have a reason to complain about school starting too early: Lack of morning light exposure is making teens exhausted, new science tells us. When teenagers don’t have enough light during the morning their body clocks are greatly affected, according to a new study from the Rensselaer Polytechnic Institute’s Lighting Research Centre (LRC).

When the blue light that comes in the morning hours is removed the onset of a hormone called Melatonin is delayed, this hormone is the one that tells the body to wake up. The study showed that teens restricted from blue light fell asleep later than those who were given the light.

One of the problems for teens getting the needed light is that schools are starting classes earlier in the day. When students are travelling to school before the sun rises their natural body clock is disrupted.

Schools also do not have to adequate electric light or daylight to stimulate the biological system. That light is needed to regulate body temperature, alertness, appetite, hormones and sleep patterns.

“The morning daylight deprived teenagers are going to bed later, getting less sleep and possibly under-performing on tests. We are starting to call this teenage night owl syndrome,” Mariana Figueiro, Ph.D., Assistant Professor and Program Director at Rensselaer Polytechnic Institute’s Lighting Research Centre (LRC) and lead researcher on the new study said in a press release.