For a better morning wake-up, swap coffee for natural light

Free Malaysia Today

08-05-2025

Morning light seems to act as a natural signal, preparing the body to wake up in better conditions. (Envato Elements pic)
For many, the start of the day is nothing short of an ordeal – it's hard to leave the comfort of your bed without using the snooze button on your alarm several times.
This is a common reflex with a scientific explanation: 'sleep inertia', a phenomenon that can leave you feeling foggy-minded for almost two hours, even after a full night's sleep. To remedy this, many people turn to a cup of coffee, hoping to chase away the morning drowsiness.
But researchers at Osaka Metropolitan University in Japan propose a gentler, more natural and, above all, more effective approach: letting daylight into your bedroom a few minutes before you wake up.
In a study published in the journal Building and Environment, they demonstrate the benefits of this through an experiment conducted with about 20 young adults, with an average age of 25.8 years, who tend to go to bed late.
The participants were exposed to three different conditions in an east-facing room equipped with motorised curtains: 20 minutes of natural light before waking up; continuous exposure to light from dawn; or total darkness until it was time to get up.
The researchers evaluated the effects of these scenarios using electroencephalograms, vigilance tests, heart-rate measurements, and questionnaires on sleepiness and fatigue. The study took place in January and February to ensure stable light levels, minimising weather disruptions.
Let the sunshine in
It turns out participants exposed to natural light 20 minutes before waking were more alert and emerged more quickly from their morning drowsiness. This method promotes a smoother awakening, significantly reducing sleep inertia.
By facilitating the transition between deep sleep and wakefulness, morning light seemed to act as a natural signal, preparing the body to wake up in better conditions.
However, it has to be perfectly timed – light that comes on too early can have the opposite effect. When the curtains opened at dawn, people felt like they had been awakened during the night, which disrupted their sleep. The key, therefore, lies in precisely timed exposure to light.
In our overlit LED-brightened environments, access to natural light is nothing short of a real luxury. And yet it is light that regulates our biological clock.
The authors of the study, therefore, advocate for better integration of daylight in housing design. And why not imagine smart houses where the curtains or blinds open automatically for a gentle awakening?
Some people already opt for artificial dawn simulators but, according to researchers, nothing beats real sunlight. Our body is naturally attuned to it, much more than to artificial light, however sophisticated it may be.
So, before rushing for your morning coffee, remember to open your curtains first. This simple gesture could well become your best hack for feeling less foggy and more energised, naturally, in the morning.