Sleep is something most of us look forward to after a long day. It's something we've especially come to cherish as adults – because let's face it, sleep is not for the weak. Sleep is great, sleep is glorious. This writer probably needs more of it.
And among sleep lovers, there are two definitive camps: Those who slumber in total darkness, and a select few who (for whatever reason) leave their night light turned on while they get some shut-eye.
However, people in the latter camp might have to reconsider their night light decision, seeing the adverse effects it may have on their bodies.
Don't reach for the light. It's slowly killing you.
IMAGE: Dollar Gill / Unsplash
According to a new study published in the journal Proceedings of the National Academy of the Sciences (PNAS), sleeping with your night light on could result with increased stress, fatigue, and even more serious health conditions such as diabetes, heart disease, and metabolic syndrome.
“The results from this study demonstrate that just a single night of exposure to moderate room lighting during sleep can impair glucose and cardiovascular regulation, which are risk factors for heart disease, diabetes, and metabolic syndrome,” said Phyllis Zee, chief of sleep medicine at Northwestern University Feinberg School of Medicine and a co-author of the study.
Even a small amount of ambient lighting could potentially do harm, such as a TV that's been left on, or the shine of bright street lamps that peer through a nearby window. In examining the effects of light on people during sleep, the researchers monitored patients who slept in moderately-lit rooms (100 lux) as well as dimly-lit rooms (30 lux), and observed the changes that went on in their bodies as the night progressed.
Participants who slept in the moderately-lit rooms experienced something called sympathetic activation. Sound like gibberish to you? Read on.
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Now, when looking at the autonomic nervous system – which regulates our heart rate, pupil dilation, digestion, and body temperature – we can split it into two categories: The sympathetic nervous system and the parasympathetic nervous system. The former helps us get through the day while we perform (often stress-inducing) general activities that require more 'effort', while the latter takes care of us when we sleep.
Those who slept in moderately-lit rooms had their sympathetic nervous system kicked into overdrive, when it shouldn't have been active at all (CC: Sympathetic activation). Essentially, the light is tricking your body into thinking it's still daytime, making it exert more energy than necessary.
The participants that experienced this also displayed elevated heart rates and a spike in how strenuously their hearts were contracting.
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When waking up the next morning, the participants also showed signs of insulin resistance – the rejection of insulin among the cells in their muscles and fat. This means they weren't able to properly produce glucose, something we need for energy. The researchers posit that prolonged insulin resistance could lead to an excess of insulin production in the pancreas, causing blood sugar levels to rise, and potentially type-2 diabetes.
“These findings are important particularly for those living in modern societies where exposure to indoor and outdoor nighttime light is increasingly widespread,” said Zee.
“If you’re able to see things really well, it’s probably too light.”
You can easily fix it, though.
IMAGE: Andalucía Andaluía / Unsplash
While everyone's sleep situation is different, there are a few easy 'hacks' that could prevent sympathetic activation while you drift off into dreamland. Here are some you should try:
1. Keep your curtains fully shut, or install blackout curtains.
2. Sleep with an eye mask.
3. Rearrange your bed so it faces away from any light source.
Don't worry, for those of you who still appreciate a bit of light in the bedroom, these tips might help:
1. Opt for a motion-activated night light.
2. Only use warm lighting, such as orange or red hues. Avoid fluorescent white lighting.
3. Make sure your night light isn't directly visible from the bed.
If you follow any of these tips, you should be okay for the most part. Of course, sleeping with no lights on at all is still going to be the best option, but it's understandable that it's not always the case for everyone.
Sleep tight!
Read more life stories:
Sleeping 1 extra hour reduces calorie intake in overweight people, study finds
Revenge sleep procrastination is real and it's ruining your life
Scientists discover way to communicate with people while they sleep and dream
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