The Winter Sunlight Paradox: explained
Snow is forecast amongst the storms, and research suggests it can change how much winter daylight reaches us.
Snow is a particular nuisance to many, bar those who want a few days off school. You leave for work in the dark, spend the day beneath office lighting, and arrive home just in time to watch the sun disappear again. *sigh*
Getting outside can feel low on the priority list for sure. But a study published in ‘Chronobiology International’ uncovered an unexpected wrinkle in the relationship between winter light and our bodies. In a group of 45 people living in Uppsala, Sweden, researchers found that snow cover increased morning light exposure and was associated with lower morning melatonin levels, greater alertness and more activity throughout the day.
The most surprising part? Snow was increasing the amount of natural light that entered peoples homes, making their dopamine levels higher. Snow reflects sunlight, a property known as albedo. Instead of absorbing much of the incoming light, a snow-covered surface reflects a greater proportion of it back into the surrounding environment.
To investigate what that might mean for people, researchers monitored 45 participants over two separate weeks: one with snow cover and one without. They used activity monitoring, diaries, and saliva samples to examine patterns of movement, sleep, and morning melatonin, a hormone involved in regulating the sleep-wake cycle.
There was an important caveat, however, as snow cover had little influence on participants' sleep quality or sleep-wake patterns.Though it may be a small study, it is an interesting one, particularly for those of us living through darker northern winters.
Light is one of the main signals our circadian system uses to keep our internal clock aligned with the outside world. Morning light helps reinforce the distinction between day and night, while light exposure at the wrong time can shift our biological timing.
The problem is that modern life often keeps us indoors for much of the day. Even on a bright winter morning, a room can receive considerably less daylight than the outdoors. This matters because feeling sleepy during the day isn't necessarily a sign that you've failed to get eight hours of sleep. Light exposure, the timing of your sleep, your individual biology, and the demands of your day can all influence alertness.
And no, the Swedish study doesn't mean we should all be booking a snow holiday to improve our wellbeing. Its participants lived at a northern latitude, where winter daylight conditions differ from those in much of the UK. You don't need snow to take something useful from the findings. Getting outdoors during daylight hours, even when it's cloudy, can help expose you to the natural light that indoor environments often lack.
Try taking a short walk during your lunch break, moving your morning coffee towards a window, or spending part of your commute outside rather than entirely underground. If you work remotely, stepping out before opening your laptop can be a more realistic habit than promising yourself a lengthy daily walk.
Snow might not improve your mood, fix your sleep or solve the winter blues. But it does offer a rather beautiful demonstration of how much the light around us matters.
