A recent abstract published in the journal of sleep has investigated the effect of artificial light exposure during sleep on melatonin levels and glucose metabolic function.
Methods: 20 adults aged 18-40 years were randomised to Dark-Dark or Dark-Light groups and studied for a 3 day/2 night duration. The participant’s habitual bedtime was determined from 1 week of prior actigraphy and sleep diary data and were allowed 8 hour sleep opportunities each night.
The Dark-Dark group slept in the dark <3 lux on both nights 1 and 2. The Dark-Light group slept in the dark <3 lux on night 1, and with an overhead light of 100 lux on night 2.
Overnight polysomnography and blood samples taken every hour for melatonin were performed. Oral glucose tolerance tests were performed on both mornings of all participants.
Results: The results showed that after a single night of light exposure, there was a significant effect on glucose tolerance tests. The effect was primarily due to increased insulin levels for the Dark-light compared to the Dark-dark group.
Conclusion: While this is preliminary research data, it is important to recognise the effect of light exposure during sleep on metabolic function. Further studies should be conducted to determine the effect of chronic overnight light exposure during sleep, and if this has long term cumulative effects on metabolic function.
I Mason, D Grimaldi, R G Malkani, K J Reid, P C Zee; 0117 Impact of Light Exposure during Sleep on Cardiometabolic Function, Sleep, Volume 41, Issue suppl_1, 27 April 2018, Pages A46, https://doi.org/10.1093/sleep/zsy061.116
