If you don’t wake up feeling ready to conquer the day, a new study sheds light, literally, on how to do that. New research reveals that allowing natural light to gently flood the bedroom 20 minutes before waking can boost alertness and banish grogginess.

According to Study Finds, Japanese researchers discovered that you can overcome that groggy, disoriented morning mood often called “sleep inertia” if you let natural light enter your bedroom just 20 minutes before the alarm goes off. The new study suggests using motorized curtains that introduce natural morning light into bedrooms, and shuts out nighttime light.

The researchers from Osaka Metropolitan University emphasize that bringing natural light into bedrooms conserves energy and improves physical and mental health. Studies have shown that Americans aren’t getting enough quality sleep. According to a 2023 survey by the American Academy of Sleep Medicine, 64% of U.S. adults use some form of assistance to fall or stay asleep. Poor awakening quality —characterized by sleepiness, fatigue, and reduced alertness — affects countless individuals daily, potentially impacting productivity, mood, and overall well-being.

The 19 study participants were divided into three groups. The first group slept in bedrooms where the curtains opened 20 minutes before waking. The second group had curtains that opened at dawn and stayed open. The third group’s curtains stayed closed until after the subjects awakened.

Ater each session, participants’ sleepiness, alertness, and fatigue were measured with an electrocardiogram, electroencephalogram, and a survey, says Neuroscience News. The researchers measured brain wave activity, heart rate, tested reaction times and the participants answered questionnaires about sleepiness and fatigue. The group who had their curtains open 20 minutes before waking performed the best overall, especially in reducing the feeling of sleepiness. Too much or premature exposure to light increased mid-sleep awakenings.

“In the future, we hope to control natural light in the sleep environment as it changes with the seasons and time of day, and to clarify how to introduce natural light that is suitable for a more comfortable awakening,” stated professor Daisuke Matsushita, who led the study.

While alarm clocks that stimulate artificial light may seem to offer a simple solution, the scientists said that natural light is superior to artificial light for stimulating our circadian rhythms. It’s important to note that the study sample was small, consisting of only 19 university students in their 20s and 30s.