Women who sleep in rooms with too much light are more likely to be overweight, a new study has suggested.
A team at the Institute of Cancer Research in London found women who slept in a bedroom with enough light to see across it at night had bigger waistlines than those who slept in darker rooms.
The study, published in the American Journal of Epidemiology, asked 113,000 women to rate the amount of light in their bedrooms, ranging from light enough to read, to too dark to see your hand.
Their responses were then compared to their body mass index, waist-to-hip ratio and other measures of obesity. The team found that these measures were all higher in women who slept in lighter rooms.
These associations were still seen after adjustments were made for factors that could be associated with light exposure levels and weight in the study participants, such as physical activity, having young children and sleep duration.
The findings have been described as “intriguing” by Professor of Epidemiology Anthony Swerdlow, who said the result open up “an interesting direction” for further research.
10 best sleeping gadgets
10 best sleeping gadgets
1/10 Philips Hue GU10 Connected Bulb Starter Pack
Use your Android or iPhone to change the colour of these Wi-Fi-connected light bulbs, casting a soothing blue before bed. They also have an alarm setting so you can use them instead of an alarm clock or, alternatively, use the dimmer setting to ease you off in the evening. £179.95, johnlewis.com
2/10 Glo to Sleep
An eyemask with a difference, this one has a strip of gradually fading blue lights which you focus on, slowly rolling your eyes upwards - engaging sleep. No batteries or wires are needed; instead the blue strips power up just by being held towards a light source for 30 seconds. £31.97, amazon.co.uk
3/10 The Alarming Clock
This clock’s face is hidden on its underside so those “clock watching” nights will soon become a thing of the past. The real boon here, though, is that it has an evening alarm, which lets you know when to begin winding down in order to develop a more defined sleep routine. Plus, the morning alarm is based on a woodpecker which is much more relaxing than loud sirens emanating from your phone. £125, alarmingindustries.co.uk
4/10 Boon Glo Nightlight
This is a nightlight for kids with three removable balls which can be picked up and taken with them around the house. Perfect for that night-time trip to the bathroom or for anyone who happens to be scared of the dark. £42.99, amazon.co.uk
Wake up to the soothing question, ‘Would you like me to pop the kettle on?’ on your phone from this Wi-Fi-connected kettle. It has four different temperatures and a keep-warm setting, as well as an auto-shut-off mode for when you’ve forgotten to refill. Works with Android and iPhone. £99.99, firebox.com
Plug any Android or iPhone into the headphone jack, load up the app and play relaxing music straight from the pillow into the back of your head. It uses bone-conducting technology so no headphones are required. £107, dreampadsleep.com
7/10 Fitbit Flex
You can track your sleep patterns with the Flex using the mobile and online dashboards, as well as tracking your activity during the day. Find out how long you spend in deep REM sleep – and then adjust your day accordingly. £69.99, argos.co.uk
8/10 Lumie Bodyclock Active 250
Wake up to the rising sun, rather than a jolting beep, every morning with the Lumie. At night you can head to bed to a sunset – it has six different light levels - and the relaxing sound of an ocean shore. £89.99, firebox.com
If you don’t need all the palava that comes with the activity monitoring of the Flex, the iOS Sleep Cycle app might be the thing for you. It monitors your movements as you sleep and finds the best time to wake you up within a 30-minute window. £0.69, itunes.com
Psychologists have long claimed that certain scents help you to fall asleep. Use the app to shower the room in a puff of lavender. The capsule can use different scents and hues of light to aid the nodding-off process. £48 for starter kit, scentee.com
However, they cautioned there was not enough evidence to advise people to sleep without any light in their room.
Dr Emily McFadden, Visiting Researcher at The Institute of Cancer Research, London, and first author of the paper, explained: “We examined the association between light exposure and obesity cross-sectionally in over 100,000 women from the UK Breakthrough Generations Study.
“Because all the information was collected at the same time, we cannot tell the sequence of events, but the associations we found are consistent with previous research examining light exposure and metabolism, and further investigation is needed.’’
The study was funded by Breakthrough Breast Cancer and The Institute of Cancer Research (ICR) and the findings emerged from their long term study into breast cancer.